STS-107, Chronicle Of A Disaster Foretold?

[Luke Davies]

Sorry if this is slightly out of context but I have decided that this thread will deal with the technical discussion of the Columbia disaster. Please use the Shuttle Columbia breaks up during re-enry (http://www.pprune.org/forums/showthread.php?s=&threadid=80192) thread for emotional/condolence type posts. [edited]

I cannot understand why you guys are all so uncritical of the Shuttle
missions.

They are serve no scientific purpose at all.
The technology is old. The "experiments" conducted on board are
laughably trivial; mainly for high school teaching programs ("let's
see what happens to watercress when we grow it in microgravity").

Not a single piece of scientific research from a Shuttle mission has
ever appeared in a decent peer-reviewed scientific journal; it all
goes into mediocre NASA house journals. The whole thing is a
preposterous waste of money.

Unmanned vehicles are safer, cheaper and have produced stunning
scientific discoveries.

The real tragedy of yesterday's accident is that seven highly
talented and courageous individuals lost their lives for a
completely pointless trip into space; the international space station
is an adult equivalent of building a tree house.

[Beausoleil]

Dear Luke,

The ISI web of science has about 2050 publications in the database involving the space shuittle. This is the latest.

Lancaster RS, Spinhirne JD, Manizade KF
Combined infrared stereo and laser ranging cloud measurements from shuttle mission STS-85
J ATMOS OCEAN TECH 20 (1): 67-78 JAN 2003

Of course the launch and repairs to the Hubble and the launch of Chandra (the X-ray observatory) were also key parts of major scientific accomplishments.

The recent flight had nothing to do with ISS, incidentally.

[Luke Davies]

Beasusoleil
okay, I agree that the shuttle was helpful in repairing Hubble (which
has been productive scientifically). But relaunching a repaired
Hubble would have been safer and cost a lot less than the Shuttle
program.

In my post I did acknowledge that many papers have appeared from
the shuttle program. But they are generally trivial, in house
journals with little or no citation impact.

For example on Pubmed today there are 849 papers from the Shuttle
trips. None of these are in the big life science journals (such as
Nature, Science, Cell, New England Journal of Medicine, Lancet or
journals of similar caliber). Instead they are in obscure journals
with titles such as "the effects of microgravity on cell wall
metabolism" and "the effects of microgravity on the mouse immune
system". These are data-dredging exercises which do no address
fundamental questions. I just now trawled through the abstracts of
the most recent 100 of these papers, and the only feeling I am left
with is how pointless most of this "research" is. If the billions spent
on manned space programs had been invested in the NIH, the
scientific product would have been dramatically better.

I know I may get some hostile reaction to this (and I appreciate the
courteousness of your email). However I mean no disrespect to the
crew who died so tragically yesterday. But we don't serve them
well by suspending our critical faculties. If the shuttle program
ends now, there will be no effect at all on scientific progress (in fact
it would be be helpful, because earmarked funds could be
rediverted into real science).

Luke

[Evo]

Luke Davies


Not a single piece of scientific research from a Shuttle mission has ever appeared in a decent peer-reviewed scientific journal


I'm not sure why you feel the need to criticise now, but this statement is complete rubbish. I used to work with data from SRTM (Shuttle Radar Topography Mission), and plenty of data from that and the SIR-C/X-SAR (Shuttle Imaging Radar/X-band Synthetic Aperture Radar) experiments were published in the Journal of Geophysical Research - which everybody (apart from you) would regard as a "decent peer-reviewed scientific journal".

:rolleyes: :mad:

[pancho]

Luke, what you say has been said many times before and it is a valid point when faced with the high cost of losing life. But the simple fact is that we are explorers, we are curious about everything that exists around us. What we know of our Universe comes from our need to find answers and that will never change. Unfortunately the pioneers of this "extension of knowledge" sometimes become victims of the quest, but that is known by all participants.

You must not forget that manned space exploration is in its infancy, but it will continue, and it will bring rewards, perhaps not immediately to us, but certaintly to our descendants. The road to knowldege and understanding is filled with danger but thankfully it has not stopped us. Remember, where there is a mountain there will be someone ready to climb it, no matter how dangerous or costly it is.

[fire wall]

Evo, what you say is correct however the point trying to be made is that the same research and results could have been attained on an unmanned spaceflight . As a pilot this does not sit well with me as I am sure many others who read such but I am afraid from a purely research/results/cost orientated standpoint it is difficult to argue against the merits of an unmanned program.

[Evo]

firewall - I completely agree. But that's not the point.

The statements were that "They are serve no scientific purpose at all" and "Not a single piece of scientific research from a Shuttle mission has ever appeared in a decent peer-reviewed scientific journal". That's just wrong. The shuttle has flown some very high quality experiments that have produced very high quality data. Could it have been done cheaper? Yes, in almost every case it could have been - but only a fool, NASA-basher or troll would claim it has done nothing of scientific value.

But that's enough from me. Not the time or place for the old manned/unmanned argument.

[Genghis the Engineer]

Although I haven't worked in astronautics for about 10 years since I discovered the joys of flight test, I still routinely come across many papers on work done in the Orbiter - albeit on the technology level.

The political point made by Luke isn't a new one. The fact is NASA decided to go in a particular way which isn't particularly cost-efficient in terms of pure science done. However it has allowed huge flexibility and statistically a good level of safety and success given the complexity of the technology. It has also forced the development of technologies that as mankind expands outwards, will be essential. You could argue that they should be working more on STS' successor, but you can't deny the huge effect the programme has had on world science.

Incidentally he's also wrong; probably the most prestigious basic science journal in the world is "Nature" and a quick search on their website found a huge number of papers where shuttle work is mentioned. I can't say I understand many of the titles, but I'm an Engineer not a biologist so this is unsurprising - I can certainly see the significance of papers like "Effect of microgravity on the crystallization of a self-assembling layered material" which is big stuff in semiconductor technology.

I suppose it's inevitable that the accident will cause a lot of open discussion, and some political points will be aired. So I'll make one of my own. I am British, and for my entire adult life I have lived under governments that have never seen any benefit in participating in manned spaceflight. That upsets me.

G

[GlueBall]

LUKE: The Shuttle's missions are not all scientific. Earlier "secret payload" missions assuredly included military/defense objectives; most probably they included the retrieval of several former Soviet spy satellites. :eek:

[NigelOnDraft]

A good link...

Most interesting part to me:
____________________________________
---------
8:59am ET
---------

A message from Mission Control about low tire pressure:
?Columbia, Houston. We see your tire pressure messages and
we did not copy your last.?

Commander Husband:
?Roger, uh ...?

The transmission goes silent for several seconds, followed by
static. This would be the last communication with Columbia or
its crew.

---------
9:00am ET
---------

The shuttle is 39 miles over central Texas at this time.

NASA PAO:
?Columbia out of communications at present with Mission
Control as it continues its course towards Florida.?

Agonizing moments go by while mission controllers frantically
try to restore communication with the shuttle.

---------
9:06am ET
---------

Mission Control:
?Columbia, Houston. Comm check??

Columbia breaks apart over Dallas, ......
__________________________________________

6-7 minutes from Loss of Communication to Break Up? I don't know how accurate this is, but I would have thought that once things start going wrong at 210,000' / M18 they go wrong very quickly, and until I saw the above, I presumed this process took a few seconds at most.

Maybe by 9:06 they mean the first reports, or confirmation? However, I am sure it will be cleared up - some of the film footage probably has a time stamp....

NoD

[airship]

I thought that a separate thread to discuss the probable causes of the loss of Columbia was called for, as a mark of respect to those expressing their sentiments over the loss of life in the first.

My concern is that an initial incident, possibly resulting in the eventual loss 15 days 22 hours and 22 seconds into the mission, namely that of the impact of foam insulation debris at launch on the shuttle's left wing was never considered dangerous enough to warrant further action.

NASA's announcements so far regarding this event include statements that any damage from the incident was assessed as not representing a danger, that there were no on-board capabilities to visually examine the area of the wing in question, nor any capability by the crew for repairing any damage sustained to the tiles.

My observation is that the tiles, and any questions relating to them are of prime importance for obvious reasons. The questions I have include:

1) Why did NASA discount the incident at launch?

2) What, if any measures did NASA take to inspect the left wing during the mission (eg) by land or space-based telescopes etc. ?

3) Had the incident at launch time been taken seriously, what options would have been available to NASA in order to save the crew (eg) launch of another shuttle, diversion of the shuttle to the ISS etc. ?

As in "normal flight" incidents, while the "primary" cause may have been an equipment failure, the reason for the eventual disaster may well lie in "human error".

[NigelOnDraft]

All your points are answered on the other thread.

<<1) Why did NASA discount the incident at launch? >>
They did not by any means...

<<As in "normal flight" incidents, while the "primary" cause may have been an equipment failure, the reason for the eventual disaster may well lie in "human error".>>
May be true, but not along the lines of the baloney you wrote above...

In short, they considered it, were unable to do anything to inspect it, and if they found a problem, what do they do? There was no means of repairing any damage even had they discovered it.

We're not talking civil aviation safety standards here. There are plenty of "critical aspects" where a single point failure = death to all. The astronauts knew that better than anyone...

Maybe before starting this link, you should have read the other thread, particularly the recent post with a link to a site with an FAQ section that repeatedly and comprehensively answers your questions.

NoD

[SaturnV]

Luke, the NIH budget for 2003 is $27 billion. In 2003, NASA intended to spend $113 million on bioastronautics, and $56 million on fundamental space biology. There have been numerous complaints, from organizations such as the National Academy of Sciences, that the NIH cannot demonstrate what scientific and medical results it is getting from spending these large sums of money. Certainly, there is not $27 billion worth of science annually being published in the peer review journals, both great and minor.

Regarding your suggestion that Hubble should have been returned to earth, repaired, and relaunched, it is impossible without the shuttle to do that. Very very few unmanned spacecraft are designed to withstand atmospheric re-entry, and none of these are intended to be re-used.

Airship, regarding the first question on your new thread, which NOD rightfully suggested that you first look at the google group FAQ link listed in a post above:

1) Why did NASA discount the incident at launch?
NASA did not discount it. NASA did an assessment based on the estimated size, weight, and velocity of the foam insulation that struck the left wing, and concluded that it was unlikely to have caused significant damage. In October 2002, a piece of insulation from the same general area of the external fuel tank pulled away and struck a cowling on one of the solid rocket motors (SRMs). NASA recovers and reuses the SRMs, and thus was presumably able to examine the amount of damage from that strike. The damage to the cowling was considered superficial.

That said, having a sizeable piece of insulation tear away from the external tank and strike either the shuttle or an SRM in two of the last three launches suggests there was:
1.) a recent change in the composition of the insulation or how the insulation was manufactured; or,
2.) a recent change in the process for bonding the insulation to the tank; or,
3.) a quality control problem in the manufacturing or installation of the insulation.

As the previous strike was in October, temperatures during pre-launch checkout and launch would not seem to be a factor.

[AMR]

NoD,

I think it's a great shame that you feel the need to bring out the insult handbook like that. Would a "Hi, I think most of your points are covered, hope you find them" not have sufficed? You know that you wouldn't have the balls to talk to strangers like that face to face, so the fact that you do so behind the shield of a Username is only going to serve as a sign of your cowardice. Feel free to be a grump but there's no place for your rudeness here.

AMR

[John Farley]

NoD

I believe that all Shuttle re-entries involve several minutes of 'routine ' comms black out thanks to a plasma field round the craft at the period of max temps.

It appears the breakup happened during this period

[BOAC]

Airship - in answer to Q3, I think the only option would have been an abort launch command which would have brought the shuttle down on an emergency strip. That decision would have to have been taken early, perhaps within seconds of seeing the bit fall off, with very little data instantly to hand and would have taken a (!)VERY BRAVE PERSON(!) to make it.

Imagine facing the NASA bosses that afternoon when the damage had been assessed as 'negligible' and YOU aborted the launch.

As it happens, it would appear to have not been negligible, and lives would probably have been saved, but ...................

[DB6]

According to the NASA spokesman on telly this morning the crew did inspect the wing whilst in space (during a spacewalk I think) and could not find any damage.

[EGLD]

I believe that all Shuttle re-entries involve several minutes of 'routine ' comms black out thanks to a plasma field round the craft at the period of max temps

I was under the impression they knew pretty much to the second when communications were to be lost

If this was the case, surely they wouldnt have been surprised to be cut off mid-conversation?

[airship]

I have read the FAQ, while useful, it does not offer any satisfactory answers. Some notable points it contains and I quote are:

1) "...one of the tasks assigned to the STS-107 crew was to take photographs of the
External Tank immediately after tank separation to see just what broke off, where it broke loose, and how big it really was. Those photos were taken, but sadly they will probably not be recoverable."
2) "Even if there had been some suspicions, there was simply no way for the crew to perform any sort of check of the underside of the shuttle."
3) "...an EVA was simply not possible as there was no EVA airlock."
4) "...the Shuttle program manager specifically stated that the crew had no capabilities to to tile repairs." (original typographic errors)
5) "...in this flight, the shuttle did not have the docking system to dock to the station." (the station being the ISS)

What one is forced to conclude is that even if the cause of the disaster was damage sustained to the heat-shield in the incident at launch, there was no way of verifying its' condition in-flight. Even if the damage could have been verified soon after, there was no way for repairs to be effected. Even if there had been a way to launch another shuttle in a resue attempt, or to divert the shuttle to the ISS, there would still have been no rescue due to the lack of the EVA airlock and docking system because of the original mission constraints.

It sounds like the builders and operators of the Titanic not only believed their vessel was unsinkable but that even when the vessel was struck, decided not to launch any lifeboats at all, and sending an SOS would have been an entire waste of effort.

[SaturnV]

John Farley,

I believe blackouts of shuttle communications during re-entry no longer happen. The shuttle communicates and transmits data in the UHF, S, and Ku bands. The Ku (and I think the S band as well) band space-ground data is sent using geostationary TDRS (Tracking and Data Relay) satellites. Using the TDRS avoids the blackout that was the constant feature of all Mercury through early shuttle missions.

Downlink data rate on the Ku Band is 50 Mbps. So NASA should have all the telemtry data to the moment of breakup and complete loss of signal.

[atakacs]

The Ku (and I think the S band as well) band space-ground data is sent using geostationary TDRS (Tracking and Data Relay) satellites. Using the TDRS avoids the blackout that was the constant feature of all Mercury through early shuttle missions. This is indeed correct.

NASA has real time data for the complete reentry phase.

Not that could *do* much

--alex

[NigelOnDraft]

airship

I apologize for the tone I used ...

<<It sounds like the builders and operators of the Titanic not only believed their vessel was unsinkable but that even when the vessel was struck, decided not to launch any lifeboats at all, and sending an SOS would have been an entire waste of effort>>
I disagree. Any book you read on something such as the shuttle will tell you there are a number of "critical" failures that are fatal - full stop.

1. The designers never considered the shuttle "unsinkable"
2. They are not able to incorporate or launch "lifeboats"
3. "and sending an SOS would have been an entire waste of effort" - frankly yes.

I think you have to remove traditional safety concepts of civil / public transportation from a vehicle such as the shuttle. If you applied these standards (lifeboats etc.) it would never fly.

You are also jumping to the conclusion that the break up had something to do with the loss of the foam on launch. I agree it is the only other "event" of note with this flight so far, but that does not mean it was the cause. Most accidents tend to have a multitude of causes, and rarely the ones that appeared obvious on day 1. I think we'll have to wait sometime longer...

If it was a tile loss / damage leading to overheating then break up I would have thought some temperature sensors would have given more warning of this? There was talk of temperature sensiors built into the body (wing underside?). Any experts out there know the point of maximum heating in the recovery?

NoD

[airship]

BOAC (I loved that airline!),

I would have to agree with your point. While allowing that an "abort" would have been very hard, if not impossible to "call", I also think that the obvious is being ignored. This is that manned-missions close to earth should be envisaged with the view that rescue is possible.

[NigelOnDraft]

<<NASA has real time data for the complete reentry phase.

Not that could *do* much >>

Not to save the crew of vehicle - however, hopefully does mean the full telemetry is recorded and able to be analysed for the investigation. Had there been a "black out" phase (as I initially thought) and the break up occurred then, the investigation would have had almost nothing.

NoD

[brockenspectre]

The last comms exchange prior to total comms/telemetry loss between Houston and Columbia was Houston acknowledging receipt of data on tire pressures. If this data indicates a pressure increase this could be due to the extreme temps on re-entry actually penetrating the heat-resistant "system" as a consequence of the integrity of the heat-resistant "system" being impaired on launch.

All total speculation at this stage.

NASA does, however, appear to be keeping the public informed this time round, after the semi-secrecy following Challenger. Let's all hope that once the data/telemetry that were subject to the contingency is married with the outcome of the NTSB/NASA investigation a cause can be established and new measures adopted for future manned missions.

There have been suggestions that an EVA was not possible, that the underside of Columbia was not able to be viewed and that there was no possibility of a dock with ISS. Let's hope future missions can incorporate some flexibility on such issues.

:cool:

[NigelOnDraft]

Some viewpoints:

"Aborting" the launch.
Once the "button" is pressed to launch, the Shuttle is committed to continue until the SRBs are jettisoned. Once these have gone, there are various "options" - however, all are hazardous. There is RTLS (Return to Launch Site) - however, I believe this has a significant chance of ending up in the sea. There is "abort to Africa" - I think this happens with 2 engines lost - again, hazardous. Then there are the safer ATO - Abort to Orbit e.g. for 1 orbit - however, this will involve a reentry. There has, I believe, been 1 abort to date for an engine failure - however, it was the mildest option, and left the shuttle in a lower than desired orbit.

I think you will find that very rarely are the Crew / Mission Control going to "call" an Abort - in practice they will be "forced" into one of the above options by onboard engine failure(s).

<<There have been suggestions that an EVA was not possible>>
Yes - the kit was not on board, nor had the training been carried out for this crew's mission.

<< that the underside of Columbia was not able to be viewed>>
Exactly - there is no mechanism, except EVA. Even the arm, when carried (it was not here) cannot "see under". I have to ask the question - if they saw damage what were they going to do?

<< and that there was no possibility of a dock with ISS.>>
A massive loss of flexibility if this is to be required. It takes a hell of a lot of energy to get into orbit. To now decide you want a different orbit is not like changing lanes on a motorway - it is like needing most of the energy supply you had at launch at your disposal again. Note when they have problems how tight the launch windows are if some rendevous if required.

<< Let's hope future missions can incorporate some flexibility on such issues.>>
I doubt it - the loss of flexibility and increase in costs would make an already dubious machine financially absolutely useless.

If you want to go down this route, I think the only way to do so is to seriously look at whether the work done by the shuttle needs to manned spacecraft. It comes down to one's moral judgements - all viewpoints of which have to be respected.

Personally, looking at the slim margins and design fundamentals of the shuttle, 2 losses in over 100 missions is probably par for the course, if not better than expected. There have been a number of VERY close shaves, and all of these are still Criticality 1 items - if they happen = total loss.

NoD

[airship]

NoD,

No problem, but thanks for your message!

It is true that I am guilty of jumping to conclusions. There could not be a discussion if we were to wait for the official declarations...

Regarding the sensors, I understood from the NASA press conference that there were 12 or more temperature sensors in the left wing area, all of which operated normally until moments before the accident. There was also some mention that simultaneous "failure" of sensors can also be due to malfunction of the signal processor or multiplexer unit through which their signals are processed. However, I understand that not all of these sensor's signals went through the same "avionics box". Needless to say, it was probably by far too late to abort re-entry by the time these anomalies occurred? If there had been significant damage to the heat-shield after launch, would these same sensors have not registered anomalies during the shuttle's orbits, when the underside would have been (repeatedly) exposed to wide fluctuations in temperature from exposure to the sun?

Your comments concerning:

1. The designers never considered the shuttle "unsinkable" - granted.
2. They are not able to incorporate or launch "lifeboats" - just as the lunar module on one of the Apollo missions provided relief (or was that just a film?!), an EVA airlock and docking system are both valid and pre-requisite for would-be rescues of near-Earth missions.
3. "and sending an SOS would have been an entire waste of effort" - frankly yes. - in this case there was no "Houston, we have a problem" message because Houston didn't think it had a problem. In space, nobody cries "Wolf"!

[TheShadow]

Interesting synopsis of possible cause is to be found

here (http://www.iasa.com.au/folders/Safety_Issues/RiskManagement/prudence.html) at this link.

Takes a different perspective and looks at some of the critical factors that can affect re-entry.....or cause catastrophe.

[NigelOnDraft]

airship...

<<Regarding the sensors, I understood from the NASA press conference that there were 12 or more temperature sensors in the left wing area, all of which operated normally until moments before the accident>>
This is an area that is interesting. NASA have commented in detail on how numerous temp (and other) in the left wing were progressively lost, and small mention of how some showed temp rises - this from Sky's site:
_________________________________________
1356: Temperatures in the housing of the left main landing gear rise. At this point the shuttle is 207,135ft or 39 miles up and travelling at 12,500mph - 18 times the speed of sound.

1358: Temperature sensors in the left wing, embedded in the structure of the vehicle, stop working.

1359: Pressure and temperature sensors for both tyres on the left main landing gear go offline
_________________________________________

What I'd really like to know is what the << Temperature sensors in the left wing, embedded in the structure of the vehicle>> showed prior to stopping working. Presumably these sensors are there to monitor the renetry, if only "after" the event.

<<Needless to say, it was probably by far too late to abort re-entry by the time these anomalies occurred?>>
They start 1 (of 3) APUs (1 needed to power flight controls and landing gear) in orbit prior to "deorbit" (a long burn to slow the shuttle down). Once deorbit starts, its coming to earth whatever! It has no fuel to regain all that energy - in fact, what little fuel it has remaining is "dumped" after the deorbit burn. But again, even if any anomolies had been seen, what to do? All one can really do is recover to earth and "hope for the best".

<<there had been significant damage to the heat-shield after launch, would these same sensors have not registered anomalies during the shuttle's orbits, when the underside would have been (repeatedly) exposed to wide fluctuations in temperature from exposure to the sun?>>
Interesting - but doubt it. The Heat Shield / Tiles protect against a short / sharp rise during renetry. In orbit things take longer, so probably expect to see fluctuations?

<<just as the lunar module on one of the Apollo missions provided relief (or was that just a film?!), >>
The Apollo missions had an escape rocket attached to the manned capsule. From Prior Launch to not too long after (it was then jettisoned) it could be used to drag the capsule away, and let them come down be parachute. Not suitable for the shuttle because its (only) way of landing is using the whole thing as a glider. They put some pole in with parachutes after Challenger, but I think the circumstances it can be used are very limited!

<<an EVA airlock and docking system are both valid and pre-requisite for would-be rescues of near-Earth missions. >>
It has a dead standard airlock into the cargo bay. However, any EVA system needs something to EVA into. What?

<<3. "and sending an SOS would have been an entire waste of effort" - frankly yes. - in this case there was no "Houston, we have a problem" message because Houston didn't think it had a problem. In space, nobody cries "Wolf"!>>
Some Prof on Sky making possible suggestion Mission Contorl knew all along recovery would be / may be fatal:
_______________________________________
Pressed by Jeremy Thompson, Prof Balogh said he was satisfied that NASA had been fully aware of the problem and had, in all probability, known all along it was potentially fatal
_______________________________________

I note from the NASA brief yesterday they only became aware of the bit falling off the day after launch - so no possibility of any decisions to be taken during the launch phase.

NoD

[Smoketoomuch]

Divert to the ISS was never possible, changing plane of orbit takes *a lot* of fuel, far more than Columbia had.

[NigelOnDraft]

TheShadow

Some interesting stuff in that link, but a lot of speculation - particularly about pilots and autopilot.

I think in yesterday's brief, NASA said 3 launches ago a similar section of tank detached. The next launch it did not, and then this launch it did. An investigation was ongoing which was to report prior to the next launch. Maybe some material change in the tank construction recently?

NoD

NB NASA news conference 2130Z tonight I think. Given the detail they gave last night - I don't think anything significant has come out since - should be interesting.

[airship]

Were NASA (or certain elements within) aware that STS-107 Columbia was doomed shortly after launch?

I have the following proposals:

1) We drink a toast to SOYUZ. Those on the ISS will be grateful that there is an alternative space program.

2) That a shuttle be permanently positioned at the ISS in order to perform SAR missions in near-Earth orbit.

3) That all future missions incorporate "crew" escape modules allowing for evacuation to another shuttle in space or re-entry under their own means.

4) That future missions rigourously incorporate the ability to "proceed by their own means to the ISS".

If future space missions are to be pursued, then it is high time that these cease to be regarded as a "dice with death".

[NigelOnDraft]

airship...

<<That a shuttle be permanently positioned at the ISS in order to perform SAR missions in near-Earth orbit>>
<<That future missions rigourously incorporate the ability to "proceed by their own means to the ISS". >>

I think you are not understanding the problems of "orbit". It is massively difficult to rendevous when it is the aim of the mission. To do so on an ad hoc basis, particularly when something has gone wrong = degraded capability is just impractical.

If you persue this line, the best place for the "lifeboat" is on earth. At that point it has the potential to be launched into the desired orbit - i.e. match that of the "stricken" craft. If you go this route, then a criteria for launch is that this lifeboat is "ready to go".

<<If future space missions are to be pursued, then it is high time that these cease to be regarded as a "dice with death".>>
IMHO you've summed it up here. What value do you place on human life, particularly when those whose lives are at risk know far better than you and I the risks, and accept them.

Interesting website:
http://nasaproblems.com

In the 2 shuttle accidents to date, I do not think an escape capsule would have been of any value...

NoD

[SaturnV]

1) "...one of the tasks assigned to the STS-107 crew was to take photographs of the External Tank immediately after tank separation to see just what broke off, where it broke loose, and how big it really was. Those photos were taken, but sadly they will probably not be recoverable."

Airship, the photography requested was apparently done because of foam insulation coming off the external tank and striking the SRM cowling during the Atlantis launch in October, 2002. It was likely done to see whether the Atlantis problem was a one-of or something recurring.

[NigelOnDraft]

Any Shuttle Experts out there...

Was the "tiling system" used in Columbia standard across all shuttles? I seem to recall something about later shuttles using a better matting system?

I note from C4 news that the original tile repair kits used on Columbia have been discontinued due "cost cutting". Just the sort of thing airship has been suggesting, although even if tile loss caused this after being hit by the tank section, no guarantees such a kit would have coped with whatever damage might have occurred....

NoD

[RatherBeFlying]

One news report mentions an observer in Owen Valley, California who noted flashes as the shuttle passed overhead which raises the possibility that pieces/tiles could have started coming off at that point.

Any such early pieces that came off would be important to the investigation, but what are the odds of finding them when they could have landed in snow, forest, desert, mountain or water after the winds have blown them off course?

The apparent intense fragmentation over a wide area makes it unlikely that all the pieces in the main debris field will be recovered, which will add to the difficulty of identifying by elimination which pieces came off first.

If a substantial span of the the left wing failed, the right wing would end up acting almost as a rudder and the left fuselage side would be exposed to beyond design aerodynamic forces at M18:(

[Bubbette]

Sally Ride said on the news this am that even if they had gone outside to inspect, they wouldn't have been able to see the area where the tiles would have been missing, and there would have been no way to replace them.

[QDMQDMQDM]

Lots of talk in the press about escape pods and how people like Buzz Aldrin have been pressing NASA for years to integrate one into the shuttles. It would be some escape pod which could work in all phases of shuttle launch and re-entry, including at Mach 18 at 200,000 feet. That has to be fantasy, doesn't it?

QDM

[nasaboy]

Crikey Firewall - no scientific benefit/publications from shuttle based missions !!.

Three letters, HST !

I may be biased as I work
at NASA GSFC but I think anyone would agree that the scientific value to mankind of Hubble (Entirely dependent on STS launch and servicing) has been considerable.

NASABOY

[Max Angle]

Was the "tiling system" used in Columbia standard across all shuttles? I seem to recall something about later shuttles using a better matting system? Endevour, the shuttle that replaced Challenger uses a different system. Not too sure of the exact details but I think the white low (lower!) temperature tiles were replaced with matting but the black high temp. tiles and the ceramic leading edge on the wing are the same.

[SaturnV]

NoD,
The tile system on all the shuttles is standard. However, each tile is unique, fitted to its particular location on the shuttle. The thermal protection offered by a tile also differs, depending on the temperature regime it is expected to encounter on re-entry. So one could not stock 50 or 100 tiles on the shuttle as spares and stick them wherever one wished, as the likelihood is that they would not fit.

Typically, about 50 tiles are replaced after each flight because of damage. The damage usually is caused by debris strikes during launch, or in-orbit strikes from micro-meteroids or space debris.

Airship, the orbital inclination for this last Columbia was 37 degrees. The ISS is at a 55 degree inclination or thereabouts. While George Lucas can easily maneuver his starships between such inclinations, real-world spacecraft would find it nearily impossible to shift inclinations to this extent.

[John Farley]

Saturn V

Thanks for the update. Glad to hear it. That should help establish the sequence of failures no end.

[ORAC]

CNN - Timeline:

A timeline of the final minutes of the shuttle flights and the hours following it (all times EST):

Additional data in italics from NASA press conference.

8:15 a.m.
Space shuttle Columbia fires its braking rockets and streaks toward touchdown.

8:53 a.m. (Over California)
Ground controllers lose data from four temperature indicators on the inboard and outboard hydraulic systems on the left side of the spacecraft. The shuttle is functioning normally otherwise, so the crew is not alerted.

08:53
20 to 30 degree rise in temperature in left wheel well over 5 minutes.

08:54 (Eastern California & Western Nevada)
Mid-fuselage bond line (bond between fuselage and top of wing on the port side) has a 60+ degree temperature rise over 5 minutes. Starboard side is nominal at 15+. Inside of fuselage wall the temperature is nominal.

8:56 a.m.
Sensors detect rise in temperature and pressure in tires on the shuttle's left-side landing gear.

8:58 a.m.
Data is lost from three temperature sensors embedded in the shuttle's left wing.

08:58 (New Mexico)
The FCS starts to add roll trim to the right. Implication is to counter increased drag on the port side.

8:59 a.m.
Data is lost from tire temperature and pressure sensors on the shuttle's left side. One of the sensors alerts the crew, which is acknowledging the alert when communication is lost.

08:59 (West Texas)
Wheel well temperatures lost. Roll trim continues to increase as the FCS continues to try to roll the shuttle to the right. Implication is that drag is continuing to increase on the port.

08:59 (East Texas)
Signal lost.

NASA have interviewed the astronomer in Owen's Valley (California) who reported debris coming from the shuttle. They have his statement and believe it is an important contribution.

[NigelOnDraft]

Interesting overview, especially "abort options":

http://science.ksc.nasa.gov/shuttle/technology/sts-newsref/mission_profile.html

NoD

[BlueEagle]

On TV here this morning an ex astronaut said that the idea of an escape pod had to be dropped because the weight penalty was too big.

Regarding EVA, even if they had been trained a NASA spokesman said there were no handles of any sort on the underside of the craft so no way could an astronaut have got there but if they could they had no facilites to conduct any repairs.

[Buster Hyman]

Thanks for that Blue Eagle. Perhaps this may change in future designs.

[overstress]

Also regarding EVA, Ron Dittemore said in the press conference today (Sunday) that even if the crew had been trained, it had long been policy not to consider tile repair. No 'kit' was available on board.

Apparently the risk of causing further damage during the EVA was too great, so the possibility was discounted

[lomapaseo]

Airship

I don't agree with your proposals and will do all that I can to veto them.

I believe that mankind must take risks in order to advance our way of life. I believe that the crew of the shuttle was aware of these risks and accepted them.

I believe that we have the proper balance of risk assessment and engineering judgement available to make future decisions regarding continuation of missions. I will continue to support the teams now in place who will have access to the facts and be able to weigh the risks vs the benefits.

[Danny]

FYI this thread will will only deal with technical discussion/speculation. Anyone who can't be bothered to read the whole thread before posting and then ends up quoting or repeating something already discussed should not be surprised if their post is removed.

Also, please refrain from using this thread to make emotional or condolence type posts as they too will be removed. Feel free to make them on the other thread, Shuttle Columbia breaks up during re-enry (http://www.pprune.org/forums/showthread.php?s=&threadid=80192)

[Wino]

For those that say that nothing is accomplished by putting man in space, I would suggest that you think about how productive flying was after man had achieved its first 100 or so flights in powered aircraft! Lots of people were killed for something that didn't move a whole lot faster than a horse and carried a whole lot less!

The simple act of flying man in space is important in the natural progesssion of humanity. If we are ever to leave this planet ( and some day we must, it is our nature to expand ) it starts with baby steps, just like the wobbly short flight the Wright brothers took 100 years ago.

The astronauts knew the risks and took them willingly. They accept that 1 in 75 chance that comes with flying on the Shuttle because this is what they do! This is not a commercial airplane ride. This is research and developement, which is not always the safest thing in the world. While not safe, it is important. The Astronauts CHOSE to go.

I admire the courage, and am comforted in knowing that they died for something they loved, at the pinacle of their game. They won't be forgotten.

Cheers
Wino

[slsman]

I am wondering if anyone on the forum can speak to this....

I seem to recall ground based video of prior shuttle re-entries some years ago which showed the shuttle at very high altitude and Mach (overflying California, I believe) without any significanltly visible trailing plume. The amateur videos broadcast yesterday seemed to me to appear quite different, in that prior to the visible breakup of the orbiter, there was a significant trailing plume behind Columbia.

Now, I've never observed a shuttle re-entry first person, nor is my memory infallible (quite the opposite!), but I am curious to compare prior entry imagery with what was witnessed on Feb 1.

My purpose is not to speculate, but this has been kinda stuck in my mind all day....

Any thoughts?

S

[Bubbette]

slsman, did you try searching for that footage under the google archive or the nasatv archive?

[slsman]

Bubbette,

Yes, good idea. I have found some imagery, so far night images of STS-93 which does clearly show a following trail.....

S

[Stand 22]

At the risk of wandering a little of topic, what happened to OV101 Enterprise, the very first shuttle. How feasible would it be for this vehicle to be used as a replacement, like Endeavour was for Challanger?

[killick]

I sense that there will inevitably be a growing conspiracy theory about whether NASA chose to ignore the damage to the left wing on launch in favour of a fingers-crossed "it'll be alright on the night" approach. I find this scarcely credible, given the customary attention to detail and precision in all of their activities, and can only conclude that any damage was deemed negligible, because this is what the evidence available indicated. Whether this evidence was sufficient is debatable in the light of subsequent events, but I find myself unable to buy into the "they knew it was doomed" school of "thought" that will doubtless find its ultimate voice in that august scientific journal The National Enquirer

[Wino]

Enterprise is not feasable at all.
That was discussed after the challenger explosion, but none of the stuff required for space is in Enterprise. It was cheaper to build a whole new orbiter after Challenger, and that is what they did...

Cheers
Wino

[Ignition Override]

Could the plume have been some, hydrogen, water tanks or nasty hydrazine which was torched ( I hate to use this word, but suspect that the crew all passed away very quickly)?

Don't comets leave trails hundreds (thou.) of miles long through space, when hit by solar particles or due to the upper atmosphere friction on a comet's frozen (liquids: methane etc?) surface?

[VH-UFO]

Excuse my engineering ignorance here, but is it possible that missing heat shields near the wheel bay could have caused heat build up in that area to a point where the tyre could have caught fire?

Just the sequence of the events below posted by "ORAC" has me intrigued.

08:53
20 to 30 degree rise in temperature in left wheel well over 5 minutes.

08:54 (Eastern California & Western Nevada)
Mid-fuselage bond line (bond between fuselage and top of wing on the port side) has a 60+ degree temperature rise over 5 minutes. Starboard side is nominal at 15+. Inside of fuselage wall the temperature is nominal.

8:56 a.m.
Sensors detect rise in temperature and pressure in tires on the shuttle's left-side landing gear.

8:58 a.m.
Data is lost from three temperature sensors embedded in the shuttle's left wing.

[ExSimGuy]

Surely there would not have been enough atmosphere at 200k feet to provide oxygen for a "conventional" fire involving the tires?

I would have thought more likely that the rising temperatures of the tire were more likely just a result of heat coming from friction of the craft (possibly less aerodynamic than it was designed, due to damage) as it passed through the thin air at Mach 18?

[atakacs]

Few questions from a total non-specialist...


Just wondering if there is any kind of flexibility in the re-entry trajectory: I understand that there is a given amount of kinetic energy to dissipate (and this was the heaviest landing in the Shuttle history); I also understand that you can not dissipate it too quickly. But assuming you accept the fact that you will miss your initial landing objective is there a possibility to choose a less stressful approach ?

Is there any real-time computer follow-up of the re-entry phase ? I understand that the telemetry analysis is clearly showing that "something" was not normal a few minutes before the actual break-up. I don't believe it would be possible for an human operator to actually pick-up the trend in real-time but it I believe that a real-time computer model & tracking system (based on the considerable database the NASA should have after 100+ missions) could have raised an alert 3 to 5 minutes before the actual break-up.

Finally, how do you achieve attitude control at those altitudes / speeds ? Is it aerodynamical (aileron / elevator) or thrust ?

This is obviously pure speculation but it seems to me that they might have had a small window of opportunity not to actually abort the re-entry but to follow a different trajectory that would significantly reduce constraints to the airframe. They would have obviously missed their intended landing point by quite a big margin, they would have probably needed to hand fly a very heavy glider but the whole point is that there *might* be a plan B after all...

[TheShadow]

An interesting article on Shuttle Safety deficiencies from the UK Observer newspaper.

http://www.observer.co.uk/international/story/0,6903,887236,00.html

[fire wall]

nasaboy, I entirely agree with your statement and might I suggest a re-read of my post will dispell your assertion

[no sponsor]

My initial thought is that thrust would be used, but in thinking about it, control surfaces may be used at those heights because of the speed and some atmosphere. Certainly, the roll-trim was being added by the on-board computer to react to the drag of the left wing, so one would assume control surfaces were sufficient to attain and execute the roll routines to lose speed (which occur at 56 degrees nose up.

(edited for spelling)

[overstress]

atacaks:

The re-entry profile is already the least stressful. This question was asked during last night's press conference and answered by Mr Dittemore

[atakacs]

I think you are not understanding the problems of "orbit". It is massively difficult to rendevous when it is the aim of the mission. To do so on an ad hoc basis, particularly when something has gone wrong = degraded capability is just impractical. Just wondering: would anyone more skilled than myself do the actual calculation and come up with the ammount of fuel necessary for an ISS rendevous vs. the on board ammount (including the desorbintg reserve) ?
The re-entry profile is already the least stressful. This question was asked during last night's press conference and answered by Mr Dittemore Thanks - I missed that one.

Would anyone care to expand on that one ? What would be the problems of doing a less agressive entry ?

[BahrainLad]

Just totally off-topic............does anyone else find it slightly peculiar that Challenger, Endeavour and Discovery were all named after British ships?

[ORAC]

Atlantis, Challenger and Columbia were named after American ships. The Endeavour and Discovery were named after Captain Cook's ships. And the Enterprise was named after a certain starship........
Shuttle names (http://www.hq.nasa.gov/osf/shuttle/orbiters.html)

[Vortex what...ouch!]

A link to a very good close up video showing the "foam" debris hiting the orbiter at launch.

http://www.floridatoday.com/columbia/debrisvideo.htm

[OFBSLF]

Would anyone care to expand on that one ? What would be the problems of doing a less agressive entry ?There is no possible "less aggressive entry." Nasa already determined the entry profile that would cause the least stress on the shuttle and that's the one they're using. Any other profile would result in more stress on the shuttle, not less. If there was a less risky, lower stress profile, they'd already be using it.

[Tricky Woo]

Ok, for once I'm on par with the rest of you on an aeronautical subject: I also know sod all about it.

For years now I've been tracking the Shuttle and ISS on the web. It has long seemed to me that the Space Shuttle as a concept has been oversold to the American public, probably in order to secure NASA the immense budgets needed to develop it, and then to keep it running.

i. It is not reusable. (Recycleable, more like, or, perhaps, semi-expendable).

ii. It is not routine.

iii. It is not safe. (i.e. Even the post-Challenger target of 1:1,000 failure ratio is not 'safe').

iv. It is not casual. (i.e. ad-hoc EVAs).

v. Once in orbit, it is not really a 'space ship', in the popular sense. (More like a sophisticated projectile, with the ability to perform minor adjustments to its orientation and orbit).


Even a brand new Shuttle system is not going to meet all of the above criteria, and unlikely to meet even two of them.

The reality is that technology has yet to catch up to the space travel expectations of the public imagination. The Shuttle was, and is, a magnificent demonstration of American technology. But even that's not enough, yet.

TW

[BahrainLad]

So which is right?

Challenger, the second orbiter to become operational at Kennedy Space Center, was named after the British Naval research vessel HMS Challenger that sailed the Atlantic and Pacific oceans during the 1870's.

http://science.ksc.nasa.gov/shuttle/resources/orbiters/challenger.html

[El Grifo]

Atakacs, you say "(and this was the heaviest landing in the Shuttle history)"

This interests me. Do we know what the Main Mission was on this particular launch.

I assume from your point, that some kind of recovery operation must have been at least, part of the Mission.

[Hwel]

The weight was due to the science modules in the cargo bay, no recovery operation was carried out.

On another note in 1979 NASA said it intended 560 shuttle flights in the first 12 years. Peaking at 65 flights in 1988. the anticipated turn around times were 2 weeks for routine ops and "a matter of hours for rescue missions" Designs were started in the early 80's for 74 seat pax modules (to ferry crews to orbiting production facilities) and liquid fuel boosters to replace the srb's allowing 50,000kg payload. Its a pity those dreams have not been recognised.

The cost for development in 1980 dollars was $3bn over 10 years.

[El Grifo]

I reiterate, does anyone know what the Main Mission was on this particular launch.

[ORAC]

BahrainLad,

The British one, someone at NASA playing a blinder...
I thought it might have been possible they acquired later, but not so.

"On 21 December 1872 the 2306 ton steam assisted corvette HMS Challenger sailed from Portsmouth on a 3-year voyage of marine exploration which laid the foundations of almost every branch of oceanography as we know it today."

"After her three years of glory, her fate was even more ignominious. Commissioned as a Coast Guard and Drill ship of Naval Reserves at Harwich in July 1876, she was finally paid off at Chatham in 1878. She remained in reserve until 1883, when she was converted into a receiving hulk in the River Medway, where she stayed until she was finally broken up for her copper bottom in 1921."

El Grifo, research. See the Mission Preview (http://spaceflight.nasa.gov/shuttle/mm-sts-107.pdf).

[whitehat]

El Grifo, the "Main Mission" was a host of scientific experiments - a Space Laboratory, if you like. A wealth of info is avaiable on the STS-107 (http://science.ksc.nasa.gov/shuttle/missions/sts-107/mission-sts-107.html) site at NASA. This is on the Missions (http://science.ksc.nasa.gov/shuttle/missions/missions.html) site which has details of previous & future flights. Further exploration of the NASA site will answer most of the other foregoing questions (or FAQs!) on the subject.

Due to the fact that there has suddenly been an uncharacteristic surge in space-interest from the press and public, no doubt some sites are a bit slow right now.

There is also an excelent and very up-to-date site at Space.com (http://www.space.com/shuttlemissions/), and many others. Hope this helps.

[Bubbette]

From the Jerusalem Post: According to news reports, a team of NASA engineers sent a report two days before Columbia's break-up on reentry stating that the damage caused to the shuttle's left wing during takeoff was greater than originally thought and could seriously affect its reentry and landing.

http://www.jpost.com/servlet/Satellite?pagename=JPost/A/JPArticle/ShowFull&cid=1044246922125

Flash presentation: http://lb.wnd.com/columbia.html

[Lu Zuckerman]

I entered a post on the other shuttle thread indicating that the Reliability of the shuttle degrades with every launch. NASA may make welding repairs to engine plumbing but they do nothing to determine if there is structural degradation. The Columbia accident investigation is more open and transparent than the Challenger accident and if it is proven that the thermal tiles were damaged during transition to orbit then NASA will have to accept full responsibility which they did not on Challenger.

I personally believe that NASA was not completely forthcoming relative to the cause for the Challenger accident. If anyone wishes to question me regarding this statement I will gladly post my reasoning. It can be done on this thread or on a new thread.

:suspect:

[PCav8or]

There is much talk about "foam" hitting the left wing on launch. Could one of you better informed technical types elaborate on what this "foam" is. Was it ice? (Heard something like that on the news). For the layman foam is what you find in your couch/mattress, so all this makes no sense to me, really.

Thank you.

[rainbow]

And ORAC,
as you are no doubt aware, another of Cook's ships was the Resolution, which heroically sailed Antarctic waters, among others.

Let the next Shuttle constructed, or derivative spacecraft evolved, be so named.

[Lu Zuckerman]

To: PCav8or

The foam is an insulation material applied to the main propellant tank. The tank is comprised of two sections. The lower section contains liquid Oxygen and the upper section contains liquid Hydrogen. The insulation minimizes boil-off while on the pad and also due to aerodynamic heating during lift-off and high-speed flight while in the atmosphere.

:cool:

[arcniz]

Tricky Woo hits the mark with his remarks about what the shuttle is not: (reusable, routine, safe, casual, or a free-roaming space ship).

The reason for most of that is practicality - it is actually still rather difficult - given our grasp of the technology and the 1960's tools in use - to launch things into space so they can return gently on demand. A lot harder than ICBM's. Some days it is impossible.

Kennedy's plan to reach the moon in the 60's was a brilliant amalgam of political, military, economic, & private goals sold to the ever-optimistic American public with plenty of flag-waving and Hollywood-style manipulation. It worked just fine for most of the near-term purposes, but the larger consequence is that NASA has had to mix in equal parts of myth and performance ever since in return for its annual billions. And it has had to rain money every year on politically well-positioned states for contracts, facilities, "Labs", and "Space Centers", especially ones in the Bush family franchise zone, including Florida and Texas, established courtesy of Kennedy's VP and successor from Texas, LBJ.

The NASA-inspired barrage of press materials, calculated leaks, fanstatic new scientific discoveries and environmental problems soluble only through spaceflight tends to closely follow the annual progress of U.S. Federal budget negotiations in Washington. If the funding calculations bog down without enough zeros in the right places for NASA and the numerous off-the books projects that feed into it and draw out of it, then reserve PR troops come in with fresh slants on Global Warming and recently discovered (or not yet discovered) asteroids that may hit the earth at any moment to wipe out all forms of life. Holywood flicks reinforcing the thought are quickly released. For many Washington-watchers, the NASA budget cycle has replaced a certain circus as "The greatest Show on Earth."

One can note with respectful awe how the current cock-up was converted within a matter of hours into a very organized campaign by NASA spokespeople and hangers-on to plead "underfunding" as the root cause and thus negotiate larger budgets for more of the same.

The real problem that plagues NASA the most is not underfunding, but arteriosclerosis. Too many NASA people have the "job for life" mentality that Government employment fosters, so they make choices to ensure continuation of programs which preserve their pension plans, rather than allowing more efficient uses of the available resources. In cases recently coming to light, some practices more resemble corruption than bureaucracy.

All that said, NASA as an institution has done a difficult job quite skillfully under an uncomfortable degree of public scrutiny.

But, at times like this, the organization tends to regress under the protective cover of institutional myths inherited from the 60's, distracting many from the underlying problems by focussing attention on a sea of marginally-relevant details.

[My Stick]

Concerning heat-resistent tiles, I just remembered something I read a couple of years ago. The Russian shuttle-program "Buran" was apparently using some other carbon-based material that was more heat-resistant and stronger. I checked, and the web-site still exists: http://www.buran.ru/htm/molniya5.htm
The website is a bit slow, but it seems the russians had a few ideas about how to make a "better" shuttle. Maybe some of their ideas could be incorporated to make the american shuttles safer? Would love to see Buran fly alongside the shuttle in the future, but I guess it's a bit unrealistic...

The show must go on.

[BahrainLad]

PS............Any chance of BAE Systems dusting off plans for the HOTOL?

[woodpecker]

Can I thank those of you who know so much more about the Shuttle than I do for some very informative postings.

Its a pity that the media does'nt have the same knowledge base available.

Obviously the majority of contributors to PPRUNE are from general/commercial aviation. So perhaps we struggle ( a little) to come to terms with what may well turn out to be a small failure causing such an accident.

I can still remember the Apollo 13 crew being able, on their departure from the command module being able to swing round in their re-entry vehicle to actually see the damage that had caused the problem. To have the Shuttle crew not being able to inspect (via cameras or a space walk) any possible damage surprised me.

After all (as someone suggested) if there was a problem with tiles (if that ends ut being the cause) there could have during a space walk been the chance to effect a "CAT Q I landing" repair.

Although this accident is very sad I still remember a slip in Tampa when we drove across Florida to watch a midnight launch (of the same shuttle). Quite an occasion, but what amazed me was the link via the car radio to the mission control RT feed.

As we watched the launch we listened to the exchanges ( in the first minute after lift-off) between the crew and launch control as numerous AC and DC electric busbars failed with finally the main rocket nozzle directional control reverting to the standby (alternate) signalling.

Throughout the exchanges I should think the EICAS (Engine Indicating, Crew Alerting System for non-Boeing drivers) and the systems panel must have been lit up like a christmas tree!

The exchanges were as if they were in a fixed base (not even full flight) simulator!

The memories of these cool and calm exchanges over the radio were as impressive as the visual spectacle.

They, together with their collegues sadly lost over Texas, are truly special people. I salute them all.

[SaturnV]

There is an interesting story in today's New York Times about tile damage on a previous Columbia mission. I think Danny discourages full text pasting of copyrighted text, so the link is here. (Registration required, but it is free.)
http://www.nytimes.com/2003/02/04/national/04WRON.html

The story relates a report on tile damage to Columbia in 1997, in which the number of tile hits greatly exceeded the norm. The tile damage was caused by foam falling off the external tank.

"Inspectors counted 308 hits. Of those, 132 were "greater than one inch." Some of the hits measured up to 15 inches long with depths of up to one-and-a-half inches. The tiles [presumably the ones hit] were only two inches deep, [some tiles are five inches thick] so the largest hits penetrated three-quarters of the way into the tiles." [Comment, if these tiles were only two inches thick, these were not located in an area of high aerodynamic heating.]

The damaged tiles were mostly around the shuttle's nose. After the mission, more than 100 tiles were taken off because "they were irreparable."

NASA also changed the formulation of the foam after the 1997 incident. The Times article states that "... to be environmentally friendly, NASA had eliminated the use of Freon in foam production. The Marshall Space Flight Center in Huntsville, Ala., later concluded that the absence of Freon led to the detachment of the foam. ...the formulation was later improved."

Finally, the Times article includes opinions from several aerdynamicists involved in shuttle aerdoynamic testing, who said 'that even slightly damaged tiles — perhaps only roughened or cracked — could generate turbulence near the tiles during the tremendous speeds of re-entry, creating potentially dangerous heating of Columbia's aluminum skin.'"
_____________________________________
Over 30 years ago when the shuttle was first proposed, the scheme (and corresponding launch rate) was for it to be mainly used as a logistics vehicle to transport hydrogen for off-loading to in-orbit NERVA rockets that would be used for manned lunar bases and manned Mars flights. NERVA rockets used a nuclear reactor to heat hydrogen as the means of propulsion; ultimately, work stopped on these engines just prior to final flight test.

Initial shuttle designs called for two air-breathing engines so it would not be a glider on return (the USAF was most interested in having an ability to land at points some distance away from the orbital track) and for the booster rocket to also be manned and return from a sub-orbital flight to a landing site.

The lunar base and manned Mars exploration missions were much like what Arthur Clarke had whirling around in space in "2001, a Space Odyssey". The basic hardware for these missions would be launched into earth orbit by the bottom stages of a Saturn V type rocket, there to be assembled by astronauts. Use of a Satrun V meant you were not constrained by the weight-to-orbit capabilitiy of a shuttle, nor by its payload bay dimensions.

But in the words of the refrain written by Kurt Vonnegut (who was a prisoner of war in Dresden when it was fire-bombed) in his novel "Slaughterhouse 5": "And so it goes."

[Buster Hyman]

Lots of good points & discussion here chaps. (circumstances excluded of course)

arcniz
As much as I'd love to believe that what you have written was a conspiracy theorists gibberish, I sadly believe that you may be right on the money here. It was one of the first things El Presidente did after the event, get mo' money from Congress. Perhaps throwing money at NASA isn't the only solution & the real problems are inherent, as you stated. (Again, I don't wish to diminish what's happened, but I'm assuming the problems at NASA were there all along)

SaturnV
How sadly ironic that in an effort to be environmentally friendly, they may have inadvertantly doomed this mission. Especially considering how much emphasis they are putting on the toxicity of the debris! (I imagine there are other motives here though)


Lots of suggested solutions are just not technologically possible at the moment. It's just like riding a giant trampoline, once at the top of the arc, there's not much else the orbiter can do(manouverability wise) prior to it's descent. Lets hope their sacrifice provides the stimulus to take the next step.

Forgot to put this in...
Did anyone else see the footage of what was purported to be the left wing in orbit during this mission? It looked like the wing root area, but I'd have thought the angles were all wrong. Regardless of that, it showed a definate dent in one section & a crack in another. Does anyone know if NASA has made a statement on this?

[oicur12]

Two points that apply,

The Gen Accounting Office in the US last week completed an audit on NASA. One auditor stated that he has never been so afraid of the safety of space fligh than at the moment (prior to the accident)

Also, retired NASA administrator Dan Goldin once stated that the space shuttle is waste of money as it achies very little.

[BOAC]

"but I'd have thought the angles were all wrong. Regardless of that, it showed a definate dent in one section & a crack in another. Does anyone know if NASA has made a statement on this"

I too could not figure out the 'angles' either, but the 'crack' was discussed on British TV last night and said to be a piece of wire taped to the inside of the window.

[steamchicken]

In the time of Mir the Russians frequently said that in their view, long-term space flight would regularly involve trouble-shooting by the crews - which everyone west of the Vistula took to be an excuse for building a dodgy space station. I wonder if their design philosophy might be worth looking at?

[ShyTorque]

Anyone know what pressures the shuttle mainwheel tyres are inflated to?

I can't help thinking about those tyres overheating and perhaps exploding in the wheel bay. Would they be capable of causing structural damage to the left wing?

[ORAC]

Nominal pressure is around 310psi at 75 degrees. Maximum 340psi. Minimum red-line 275psi.

[BlueEagle]

As with aircraft tyres I expect the Shuttle tyres would have plugs that melt and allow the gas/air mixture to escape before it can explode.

[PickyPerkins]

In connection with the New York Times article (http://www.nytimes.com/2003/02/04/national/04WRON.html) linked to by SaturnV: “Engineer's '97 Report Warned of Damage to Tiles by Foam”
-------- Start quote --------
… The newly released NASA video shows a whitish object soaring backward, striking the Columbia's left wing and bursting into a cloud of dust. …
-------- End quote --------

Couldn't it be just as likely that the cloud is largely powdered tile?
http://home.infi.net/~blueblue/_uimages/pi.gif

[PETERJ]

FLIGHT PROFILE.....

Was the Shuttle flying straght and level at 200,000 feet, mach 18 at a pitch up angle of between 28 and 38 degrees when the disaster happened ?

Was it flying under computer (ie non-manual) control ?

At what stage in the flight profile are the high angles of bank (50 + degrees) normally iinitiated ( Altitude/speed/ distance from touchdown /computer or manual ?).

Are slowing down s-bends optional or obligatory in the standard flight plan.?

Yes I know that this will all be covred in the final Report but in my sadness I am battering my brains for an explanation of this heroic disaster and I don;t want to believe it was just happenchance !!!!!!!

Any info much appreciated

[arcniz]

Buster writes:

As much as I'd love to believe that what you have written was a conspiracy theorists gibberish, I sadly believe that you may be right on the money here. It was one of the first things El Presidente did after the event, get mo' money from Congress. Perhaps throwing money at NASA isn't the only solution & the real problems are inherent, as you stated. (Again, I don't wish to diminish what's happened, but I'm assuming the problems at NASA were there all along)

I'm not sure what you mean about 'conspiracy' theory, but since 'conspiracy' is a serious legal accusation, I must take exception to your comment.

I do not claim to be aware of any 'conspiracy' at NASA in regard to this particular matter, nor do I contest the integrity of any specific individual. My contention was and is that NASA has become ever more lethargic due to bureaucracy and the unique problems of reinventing its financial raison d'etre each year.

The politics of it are about money and power, much like ancient Rome, but with different hats. Politics is a sanctioned form of conspiracy that always involves some degree of intrigue and rapacity. Certain military programs, NASA, and the 'Federal Labs' are great patronage honeypots that each Presidential administration inherits to manipulate for political purposes - both in terms of the money they can spend directly and for the potential that focussed scientific research has to boost some industries at the expense of others. The elected representatives in Congress are not oblivious to this process and actively maneuver to benefit their constituents from it during the push and pull of legislative negotiations.

[25F]

PeterJ, and others,

The "sane participants" of the sci.space.shuttle newsgroup have put together the following FAQ:
http://www.io.com/~o_m/columbia_loss_faq.html

Shuttle re-entries are normally under computer control until just before landing. There's an extensive sss thread on the subject here:
http://groups.google.com/groups?hl=en&lr=&ie=UTF-8&threadm=Xns92D529B3D9CC6marypegg%4062.253.162.109&rnum=5&prev=/groups%3Fq%3Dmanual%2Blanding%2Bgroup:sci.space.shuttle%26hl %3Den%26lr%3D%26ie%3DUTF-8%26selm%3DXns92D529B3D9CC6marypegg%254062.253.162.109%26rnu m%3D5

The following info on flight profile is taken from the FAQ. I hope this isn't considered an excessively long post:

===================================
* Where and when did Columbia break up? (Altitude, speed, time, etc.)
===================================

Ground controllers lost communications with Columbia at 7:59:22am
CST, at a mission elapsed time of 15 days, 22:20:22. At the time,
the shuttle was at an altitude of 207,000 feet (63,000 m), traveling
at Mach 18.3, approximately 37 miles (60 km) above the Dallas-Fort
Worth Metroplex region of Texas.

===================================
* What was Columbia's status prior to breakup?
===================================

First, let's look at Columbia's reentry profile. The Shuttle has 3
distinct phases to the standard reentry profile:

1) Thermal Control Phase. This lasts from Entry Interface, when the
first aerodynamic effects occur, until a speed of approximately
19,000 ft/sec (12,900 MPH, 11,200 kts, 20,900 km/hr) has been reached.

2) Equilibrium Glide Phase. This is flight at a constant attitude as
the deceleration due to drag builds up to approximately 1G.

3) Constant Drag Phase. The 1G deceleration is held until the orbiter
enters the Terminal Area Energy Management interface, after which it
is flying as a conventional, but very heavy and fast, glider. This
is usually 52 NM (59 SM, 94 km) from the landing site, at an altitude
of 83,000', and a speed of Mach 2.5 (2500 ft/sec, 760 m/sec) The
orbiter slows to below Mach 1 at about 49,000', 22 NM (25 SM, 40 km)
from the runway.

Columbia was either at the end of the first phase, or the beginning
of the second phase when she broke up.
The first phase begins when the orbiter is oriented tail-first,
and the OMS engines fire to reduce its speed by about 300 ft/second
(90 m/sec). The reaction control system then orients the orbiter nose
first to prepare for reentry. At roughly 400,000 ft altitude (122
km), Entry Interface is considered to occur. This normally takes
place 4,400 NM (5063 statute miles/3160 km) from the landing site.
The speed at this point is about 25,000 ft/second (7600 m/sec).
At this point the orbiter is maneuvered to 0 degrees roll and yaw,
and a 40 degree angle of attack. The flight control system at this
point uses the Reaction Control System to keep things aligned. The
forward RCS engines are turned off at the entry interface, and the
aft RCS system is used to maneuver the spacecraft.

The spacecraft must dissipate the tremendous amount of kinetic
energy it has. It does this by varying the amount of aerodynamic
drag that it presents on the way down. This generates a lot of
heat because of the speed of the shuttle. This heating is controlled
by changing the speed of the shuttle in small amounts. This is done
by varying the aerodynamic drag of the shuttle. Most aircraft do
this by changing the Angle of Attack. When you pull up the nose,
an airplane tends to slow down, unless an engine is used to counteract
the drag. For a re-entering shuttle, the angle of attack must be
held constant to prevent the structure from overheating.
The shuttle controls drag by rolling into a series of 'S' turns along the
flight path. Increasing the roll angle of the orbiter moves the
direction of its lift (perpendicular to its wings) away from the
vertical, causing it to descend faster. These S-turns are used to
fine tune the energy level (A fancy way of saying altitude and
airspeed) of the orbiter, something like skiers turning while going
downhill to control their speed. When a dynamic pressure of 10
psf is reached (EAS of 62 MPH (100 km/hr)), when the orbiter's
ailerons become effective for roll control. At that point, the roll
RCS engines are deactivated. At a dynamic pressure of 20 psf (EAS of
85 MPH(138 km/hr), roughly), the elevators on the orbiter become
active, and the RCS pitch engines are deactivated.

In the Equilibrium Glide Phase of the reentry, the spacecraft is
flown to maintain a constant drag level, where the flight path angle
remains constant. This is maintained until the deceleration of the
orbiter due to drag is about 1G.

In the last phase of the reentry, the 1G deceleration level is held,
reducing the angle of attack as necessary, until the Terminal Area
Energy Management interface. The RCS system continues to control
Yaw until the rudder become effective at around Mach 3.5.

Columbia was lost either at the tail end of the Thermal Control
Phase, or the early stages of the Equilibrium Glide Phase. The
ailerons and elevators were providing control, (the Q at that point
was around 75-80 psf, or an EAS of about 170 mph (275 km/hr)), and
yaw was being controlled by the RCS thrusters in the tail.

Late reports before this writing this indicate that the Flight Control
System reported that it was correcting a left yaw/roll just before
breakup.

[Bubbette]

The latest I'm hearing is that nasa knew there was trouble, they denied that using CIA spy satellites would have been able to see the tile damage, despite the CIA statements to the contrary, and they could have rescued them if they told them to start conserving from the day they saw the damage ie day two. They've also found debris in Califiornia and New York.

[aardvark2zz]

25F
"2) Equilibrium Glide Phase. This is flight at a constant attitude as
the deceleration due to drag builds up to approximately 1G.

3) Constant Drag Phase. The 1G deceleration is held until the orbiter
enters the Terminal Area Energy Management interface, after which it
is flying as a conventional, but very heavy and fast, glider. This
is usually 52 NM (59 SM, 94 km) from the landing site, at an altitude
of 83,000', and a speed of Mach 2.5 (2500 ft/sec, 760 m/sec) The
orbiter slows to below Mach 1 at about 49,000', 22 NM (25 SM, 40 km)
from the runway. "

The decceleration has to be greater than one. Otherwise it is actually accelerating due to gravity and drag forces not being canceled out.

[ORAC]

Interesting to see that the deputy chief of the astronaut office is an Australian. Dr Thomas (http://www.jsc.nasa.gov/Bios/htmlbios/thomas-a.html)

[PickyPerkins]

Question for 25F
--------------------
Don't some of the numbers in your very infomative post need some medical attention? e.g.

"orbiter slows to below Mach 1 at about 49,000', 22 NM (25 SM, 40 km)"

"place 4,400 NM (5063 statute miles/3160 km) from the landing site"

Cheers, http://home.infi.net/~blueblue/_uimages/pi.gif

[25F]

Picky, just to make it clear to all, everything after "excessively long post" is taken from the sci.space.shuttle newsgroup. The info was put together in something of a hurry, while trying to fend off hundreds of newbies asking why the Shuttle didn't just go back to the ISS...
Your first quote is altitude in feet followed by distance from landing. The second one does need fixing.

Aardvark, I'm afraid I don't quite get your point. I think we can take it that acceleration here is measured with respect to the inertial frame of reference of the shuttle itself. It starts at zero, in orbit, and increases during re-entry. My reading of the text is that it is held to about one G. Typical maximum G is 1.6. (For Soyuz craft it is 4-5G, if not more).

[CAT1]

In his post, steamchicken suggested that Russian design philosophy might be worth looking at. I have to agree. They try to keep things simple. In the days of the cold war, when the space race was in full swing, the Americans spent millions designing a pen that would work in zero G (the "space pens" that can now be bought for five quid from mail order catalogues).
The Russians had a far better idea. They used pencils.

[ORAC]

Just did a search for previous report of damage which might be relevant and found two.

STS-27 Mission report:

Initial post-flight inspections of the exterior surface of the Orbiter revealed significant tile damage with 298 damage sites greater than 1 inch in area, and a total of 707 damage sites on the lower surface of the vehicle. The area of major damage was concentrated outboard of a line from the bi-pod attachment to the external tank (ET) liquid oxygen umbilical. One tile was missing on the right side slightly forward of the L-band antenna. Also, there were many damage sites consisting of long narrow streaks with deep gouges.

NASA Reference Publication 1390:

(STS-45) The Atlantis suffered 2 gouges on the upper portion of the right wing leading edge. The most probable was a low-velocity (relative to the spacecraft) debris impact on orbit or during re-entry. However, Johnson Space Centre engineering has not ruled out prelaunch or ascent debris as the cause of the damage. This particular event raised concern about the consequences of a higher energy impact to the integrity of the spacecraft.

[Bubbette]

I think Nasa knew, or had the ability to know, by using satellites used for spy missions, the extent of the damage, and the consequences for a return to earth. No one at NASA had the balls to speak up.

[OFBSLF]

After all (as someone suggested) if there was a problem with tiles (if that ends ut being the cause) there could have during a space walk been the chance to effect a "CAT Q I landing" repair. Yesterday, one of the AM talk shows interviewed a former shuttle astronaut who had been on a team trying to develop a tile repair kit for the shuttle. He said that no matter what they tried, the adhesives that worked just great in standard conditions did not work in a vacuum. Their conclusion was that 1) any repairs attempted in space would not work and 2) attempting to repair in space would likely damage other tiles in the process, making the situation worse, rather than better.

Only possible solution would have been a rushed rescue mission.

[25F]

CAT1, the space pen story is a nice story, but it is just that:
http://www.snopes.com/business/genius/spacepen.htm
For early flights both "teams" used pencils. The Fisher pen company developed the space pen at their own expense. It has been used on all manned space flights since Apollo 7, according to all the references I can find.

Bubbette, could you provide references for your claims, please? Debris in New York, unless that's the New York, Texas, Cheesecake Co., seems somewhat unlikely. Similarly I have yet to see a credible rescue scenario anywhere. Lastly have you a reference for the CIA stating that they could have inspected the shuttle from their satellites?

[Reckon]

It seems that the NASA line is that even if they had been aware of the problem there was nothing to be done. One question I have is that whether reducing the weight of the shuttle could have improved the odds.

Could a reduced weight have helped by:-
- Changing the heat 'map' on the tiles due to an altered angle of attack?
- Reducing the maximum temperatures to be encountered?
- Increase manouverabilty (vary pitch to vary heating, counter/mitigate left yaw/roll ) of the vehicle?
- Less stress as on ailerons/elevators etc?
- Reducing the speed at which (no gear?) that the astronauts would have had to bail out?

Maybe the answer is that thay had no means to do this. Could they have:-

- Dumped the module in the cargo bay?
- Dumped at much as possible through an (fitted?) airlock?
- Dumped air, used (below safe min) fuel

[arcniz]

CAT 1: Pencils are not the best thing to have in a closed electronics-filled space with little or no gravity because graphite dust conducts electricity. Tiny particles of conductive floating residue would have some potential ability to bolix onboard sensors and electronics.

[Bubbette]

25F I heard the debris in New York late last night on the local radio--maybe I misheard or they misspoke because it's not on the website (www.1010wins.com). Re the spy satellite, my friend told me that; I will check with him for a source. And now, on the late night radio conspiracy show (http://www.coasttocoastam.com), they're saying it was terrorism; or sabotage. He's citing the report after the Challenger stating that the tile-layers were not using the glue correctly. . . (hey--I'm just reporting what they're saying--this I don't know if I believe).

[Zoner]

High altitude lightning? I don't know if such a thing is possible, but this story I just ran across raises some interesting questions.
http://www.sfgate.com/cgi-bin/article.cgi?file=/c/a/2003/02/05/CAMERA.TMP
"Top investigators of the Columbia space shuttle disaster are analyzing a startling photograph -- snapped by an amateur astronomer from a San Francisco hillside -- that appears to show a purplish electrical bolt striking the craft as it streaked across the California sky. "

[BahrainLad]

The problem with Bubbete's view that they could have conserved supplies and been rescued is that you run the high risk of loosing another shuttle and another crew.

If this problem with the tiles was an inherent design flaw then I would salute the commander willing to take another shuttle up within a 2 week prep period; but he would be making a very large risk indeed. Technically, there would be a 1 in 107 chance of endng up in the same position as Columbia, although with twice the crew dead and an abandoned shuttle doomed to burn up in the atmosphere.

[2WingsOnMyWagon]

Just seen this on ceefax:

NASA REJECTS U.S. SHUTTLE DAMAGE THEORY

A piece of insulating foam is no longer thought to have caused the break-up of the Columbia space shuttle, Nasa says

The probe had focused on damage to tiles under the left wing, which it was thought could have caused by a chunk of foam insulation on take-off.

But Nasa said the foam debris was neither heavy enough nor traveling fast enough to cause the damage.

The probe will now focus on the automatic control system.

BBC News / In depth, shuttle disaster (http://news.bbc.co.uk/2/hi/in_depth/sci_tech/2003/shuttle_disaster/)

[SaturnV]

Electrodynamics is far from my field, but I was struck by the great interest NASA took in a series of photographs taken in San Francisco as Columbia was flying overhead, and which MAY show a purple streak striking the spacecraft.

Excerpts from the story in today's San Francisco Chronicle:

Of particular interest is a startling image taken by an amateur astronomer in San Francisco, which appears to show a purplish bolt of lightning striking Columbia at it streaked across the predawn skies.

NASA dispatched former astronaut Tammy Jernigan, who has flown five times on the shuttle, to pick up the photos and the camera itself. She delivered them to a NASA jet at Moffett Field, where they were to be flown to Texas on Wednesday. Jernigan said she did not know what to make of the image but agreed it needed to be analyzed.

"We sure will be very interested in taking a very hard look at this," she said while examining the picture in the photographer's San Francisco home.

The images could turn out to be the result of a subtle jiggle of the
camera or might depict some rare electrical phenomenon in the zone known as the ionosphere, more than 40 miles above Earth.

Photo analysts should be able to match the location of the strange lightning-like image with a precise point in space and time during the orbiter's descent. That's because the photograph also depicts a crisp field of stars in the background, which provide astronomical reference points.

The amateur astronomer, who does not want his name released, said he believes he snapped the images at 5:53 a.m. Saturday.

Scientists at the University of Alabama at Huntsville published a paper on plasma jets is space. See:
http://bex.nsstc.uah.edu/RbS/UGRANT/ugrant.html

A paragraph from the paper says thus in discussing ionospheric jets:

Note that charge separation occurs as soon as the dipole gradients are seen by the sunward convecting neutral plasma. It is generally assumed that the high conductivity of the cold plasma (assumed to be zero temperature, and therefore oblivious to magnetic gradients) allows the electrons to be redistributed in a
way to maintain quasi-neutrality. Recent observations show that this assumption of sufficient cold plasma fails during a magnetic storm, and real charge separation may occur. Under these conditions, cold plasma from distant regions is required, and indeed accelerated to shield the space charge. POLAR made
recent measurements of a 30 keV field-aligned potential drop during a small storm, that populated the ring current with accelerated ionospheric plasma (Sheldon98a). Thus the ring current can be explosively driven on timescales of minutes by upward ionospheric jets, as is evident in high time resolution
magnetograms.

The weblink containing the full paper includes a photograph of a plasma jet that was created in a laboratory chamber. Care to guess what color the plasma jet was?

I also came across a reference in a paper on space weather to temporal changes in ion density depending on the season and time of day. At northern mid-latitudes, the ion density is most negative in mid-winter and just before dawn. Columbia transited the San Francisco Bay area in the hour before dawn (PST).
http://www.agu.org/sci_soc/eosbuon.html

I did come across several papers by Russian scientists on kinetic forces associated with plasma jets, but didn't grasp a good sense of how weak or powerful such jets might be.

[Squawk7777]

Here is an interesting view from the Nexrad Loop (http://story.news.yahoo.com/news?tmpl=story&u=/030201/161/368x4.html)

All these discussions bring up a question. I understand that a speed limit is likely to be caused by the rising temperature during re-entry, but apart from that does the shuttle have a Mmo?

7 7 7 7

[ORAC]

National Public news just reported that, according to AW & ST, the USAF has given NASA photographs of the shuttle. The photographs reveal major structural damage at the root of the left wing/fuselage join.

----------------------------------------------------------

KENNEDY SPACE CENTER, Florida (CNN) -- Photographs taken by an Air Force tracking camera shortly before the space shuttle Columbia disintegrated show serious structural damage to the shuttle's left wing, an aviation magazine reported Friday.

The images, captured about a minute before the shuttle broke apart, show a jagged edge on the left wing structure near where the wing begins to intersect with the fuselage, according to a report in Aviation Week & Space Technology. Columbia's right wing and fuselage appear normal in the photos, the magazine said.

The damage to the left wing indicates either a small structural breach, such as a crack, or that a small piece of the wing's leading edge fell off, according to the magazine. It said NASA investigators at Johnson Space Center in Houston, Texas, are analyzing the pictures.....................

[RatherBeFlying]

Aviation Week & Space Technology Article (http://www.aviationnow.com/avnow/news/channel_awst_story.jsp?id=news/shuttle2_news.xml)

[PickyPerkins]

From the STS-107 SECOND DAILY REPORT on the NASA site (I think that’s where I got it from):

-------- Start quote ---------
STS-107 SECOND DAILY REPORT …….. At approximately 81 seconds mission elapsed time (MET), a large light-colored piece of debris was seen to originate from an area near the ET/Orbiter forward attach bipod. The debris appeared to move outboard and then fall aft along the left side of the Orbiter fuselage, striking the leading edge of the left wing. The strike appears to have occurred on or relatively close to the wing glove near the Orbiter fuselage. After striking the left wing the debris broke into a spray of white-colored particles that fell aft along the underside of the Orbiter left wing. ………..
-------- End quote ---------

However, in all the news conferences the debris was said to have struck the underside of the wing. http://home.infi.net/~blueblue/_uimages/pi.gif

[jet_noseover]

Interesting reading

http://www.msnbc.com/news/867336.asp?cp1=1

[PickyPerkins]

The figure below is from a paper “Risk Management for the Tiles of the Space Shuttle” by Elizabeth M Pate-Cornell and Paul S Fischbeck, written Jan-Feb, 1994.

The darkest areas in this figure are concluded to be the highest risk areas, and are located on the fuselage near the wing glove.

The report noted that the highest risk areas were not the hottest areas.

The estimated risk was made up of a combination of many factors including the chances of debris from the main tank hitting the Shuttle, where they would hit, the chances they would damage a tile, and the consequences of a burn through to equipment underneath. The study seems to have been limited to tiled areas (i.e. it didn’t cover the carbon leading edges).

http://home.infi.net/~blueblue/_uimages/Risk.gif

I do not understand why this figure is not symmetrical in either its outline or in the shading representing risk. I assume the diagram represents the bottom surface only. If so, the left fuselage/glove area is actually somewhat less vulnerable than the right.

I don't what other people think, but in the vidio I have seen the debris does NOT seem to hit the fuselage at all. http://home.infi.net/~blueblue/_uimages/pi.gif

[vaneyck]

Picky Perkins--
The NY Times of Feb. 5 ran an article summarizing the paper you cite, under the title NASA Was Told in 1990 About Vulnerable Protective Tiles Here's the URL: http://www.nytimes.com/2003/02/05/national/05FOAM.html?pagewanted=print&position=top

The article, which is well worth reading, focuses on the wheel wells, pointing out why they are potential trouble areas, but it also explains by implication why the diagram of danger areas is asymmetrical. (By the way--the Times article has a similar but simplified diagram of the shuttle, but the paper it cites, by the authors you name, is dated 1990. A minor mystery, probably not worth puzzling over.)

The Times authors say,
"Tile damage in the wheel areas was relatively high, as it was along the whole right side of the underbelly. That, they found, was because foam insulation had flown off two long pipes that run alongside the external fuel tank."

In addition,"To the data on tile damage, the scientists added temperature readings of where the shuttle tiles became hottest and were most likely to burn through. Dr. Paté-Cornell said the wheel areas got unusually hot during re-entry because their doors created a 'discontinuity' in the tiles that would disrupt the smooth flow of air over the shuttle's belly."

The authors of the cited paper then correlated the tile-damaged and high-heat areas with vulnerable parts of the shuttle: places where hydraulic lines ran underneath, as well as sites of hydrogen and oxygen tanks.

[PickyPerkins]

vaneyck

Thanks for the interesting NY Times article. The reason for the seeming discrepancy in the dates is given in the article: “They did their study for NASA in 1990 and published three academic papers on their work in 1993 and 1994.”

The diagram seems to have been omitted from the on-line version you linked to.

The NY Times article seemed to me to be somewhat misleading in that it did not specifically say that improvements were made to the doors as a result of the study:
--- Start quote from the 1994 paper ------
… tiles in some particularly hot areas had to be redesigned. For example, the tiles in the elevon cove (the gap between the rear flaps) and on the edges of the main landing doors had to be reinforced. After these adjustments, normal heat loads were not considered a problem for well-bonded tiles. This is why our analysis focuses mostly on the possibility of tile debonding because of a weak bond or the impact of controllable debris. …
--- End quote -----------------------------------

One of the surprising findings in the 1994 paper was that a few (e.g. 12) tiles were found installed with no bond at all. They were only kept in place by friction with adjacent components. Also, workers were given a quota of tiles to install in each shift. They found they could speed up the cure of the adhesive by spitting on the adhesive, and this aided them in meeting the quota. However, once in space, resin which had been spat on reverted back to a liquid! The paper implied that all these aspects were taken care of long ago as a result of the study.

Another interesting NY Times article (http://www.nytimes.com/2003/02/07/national/nationalspecial/07BOUN.html) says that roughness can trigger turbulence at much higher speeds than normal (e.g. Mach 18) and lead to much higher than normal heating, and that this had happened to Columbia before. Apparently a much-studied phenomenon. It can happen on one or both sides of the a/c. http://home.infi.net/~blueblue/_uimages/pi.gif

[DrSyn]

There has been a lot of speculation about the tiles since the investigation started, and Ron Dittemore, for whom I have the utmost respect, has been reluctant to identify them as the culprit. Having followed this mission, and most others, from start to finish (and this time into the sad beyond), I sympathise with his caution.

It is undoubtedly one of the most critical features of the Orbiter and is only put to the test during re-entry when the craft is exposed to the greatest thermal and aerodynamic stress. The max q occurs at around the altitude and velocity at which Columbia was observed to have failed (re: previous questions). However, from the earliest flights, Shuttles have returned safely to Earth with some remarkable tile damage without suffering nail-biting damage to the underlying "conventional" structure. Many improvements to tile bonding, and related issues, have been implemented over the years.

The Tile Papers

Just to clear up a couple of points raised by PickyPerkins & vaneyck in respect of the (superb) Paté-Cornell/Fischbeck paper Risk Management For The Tiles Of The Space Shuttle (et al):

Caution: Please note that the following links may require long download times on slow modems.

1. The original was first published in 1990 (http://spaceflight.nasa.gov/shuttle/investigation/tps_safety.pdf). The (shorter) "RIsk Management" paper appeared in 1994 (http://www.nasa.gov/formedia/MP_risk_tiles_1994.pdf) and also won an award. I think it gained further awards in later years (not relevant to this thread, however). These documents are not "proper" PDFs in that they are effectively photocopies on Acrobat. Not exactly leading-edge technology :(

2. The apparent asymmetry in the diagram on Picky's post is explained by, "We found that 15 percent of the tiles account for about 85 percent of the risk and that some of the most critical tiles are not in the hottest areas of the orbiter's surface" in the above papers. . . . . IE: It depends on what's underneath the tile (hope that helps).

Whilst this excellent audit did result in significant changes to tile processing and inspection, it did not (and may not have been intended to) discuss loss of the Reinforced Carbon-Carbon (RCC) sections of the heat shield in depth.

KE=½MV² . . . or not ?

And here lies the rub (sic). What really happened when that "2.2 lbs (1kg)" chunk (http://www.floridatoday.com/columbia/debrisvideo.htm) of ET insulation struck the RCC leading edge of the left wing at a relative speed of [±]1090 ft/sec (330 m/sec) ? That's a KE of 40,200 ft lb (54,500 j). Where did it all go ? Did it simply fragment on impact thus dissipating the KE, or did its MV² weaken or fracture part of that most critical component ? Quite a punch, though. Imagine the effect on your head at such velocity. Ouch ?

Unlike the tiles, the rigid RCC leading-edge sections are bolted to the wing with more flexible separators between each section. Behind them is further thermal protection, eventually leading to the flat front of the leading-edge aluminium wing box. Forget the razor-like profile of the old F-104 Starfighter wing, this STS baby is 5 ft thick at max chord. That's one heck of a speed brake if even one RCC fairing is removed at Mach 20 . . . . near the time that Max q was achieved and the anomolies began to appear.

Focus! . . . Focus!

In many aviation-related accidents there have always been "Godarnit" impairments to otherwise vital evidence. What a shame that the critical hi-res cameras, that could have produced photo qualities that we have marvelled at on most post 51-L launches, were out of focus on this particular launch. Is this simply complacent lack of attention to QC, at the relevant sites ?

Equally unfortunate is the much-circulated picture of Columbia from the Starfire Optical Range (SOR, Kirtland AFB, NM) which, according to the publicity (http://www.thenewmexicochannel.com/news/1955443/detail.html), is allegedly capable of resolving a 1 ft object at 600 miles (OK, I know there are two optical devices). The picture of Columbia at a mere 40 miles-up is unimpressive. It was released to the press as a negative and, either way, is inconclusive but significant. It just appears to show an anomaly on the left wing leading edge where RCC sections should be. It also shows a more pronounced trail from the left wing immediately aft of that anomaly. It is of course presently a coincidence that drag was observed to be building up on that side at the time.

http://ourworld.compuserve.co.uk/DrSynHst/images/Kirt-107.jpg

Dittemore is now (with great relief, no doubt) handing over to an "independent" BOI. I am sure it will do its job well. Be patient. I doubt it was the tiles. The truth will out.

[Few Cloudy]

Very interesting stuff. For a space laymen such as myself, are the flight controls on the Shuttle already in use during the exit phase? The point being - would a left yaw tendency already have been noticeable during the climb at any point?

[atakacs]

The picture of Columbia at a mere 40 miles-up is unimpressive. It was released to the press as a negative and, either way, is inconclusive but significant My understanding is that this is a degraded image. The original, forwarded to the investigation team, should have an order of magnitude better resolution.

Sorry, can't quote any source...

--alex

[RatherBeFlying]

DrSyn, Could you explain further the 330m/s you give as the relative velocity of the chunk that came off the ET.

I would expect the relative value to be somewhere between the shuttle velocity and zero depending on how long it would take the chunk to accelerate to its falling velocity.

Drag and the thin air density at that altitude would be factors in this acceleration and I don't have the mathematics to work this one out.

[DrSyn]

atakacs, you forgot to add at the end, ". . . or they'll shoot me!" You are quite right. I should have put a ;) after that little dig! As they boldly advertise Starfire's "1ft @ 600 miles" capability, the public release of an ultra lo-res blur seemed slightly bizarre to me. It would be sad indeed if that expensive bit of kit were unable to provide the investigators with such potentially vital evidence.

RBF, useful question - the relative velocity was not my calculation. ½MV² is about the limit of my practical Physics these days! It was based on the Jan 17 routine post-launch debris review which (I think) estimated that the debris had reached 744 mph / 1090 ft/s at the time of impact. I now note that in the Jan 21 report, that estimate had been reduced to "730 ft/s" (222 m/s) which would make the KE about 29,570 j (40,090 ft lb). Notwithstanding any math error on my part (!), those Jan estimates are a tad "ball-park" and may not have had total unanimity in their conclusions. Still, in the wrong place - quite a whack methinks. Enough to weaken a RCC panel or its attachments?

I am sure they'll work it out and have the remaining fleet up and running before too long. Good luck Admiral Gehman and team.

[DrSyn]

Sorry, FC, I didn't mean to ignore you! Yes, the aerosurfaces do carry out various functions during the very early part of launch and then position to provide wing load relief. Otherwise all "steering" is effected by thrust vectoring.

Like all space rockets, the shuttle stack climbs initially at a steep angle to get it into the less dense upper atmosphere ASAP, before accelerating rapidly down range. If any abnormal drag had occurred during ascent, the necessary corrections should be evident from the telemetry. I guess by now they have looked through that in great detail.

Any missing tiles or weakened RCC component would probably not be a major factor until the high stresses of re-entry. Whatever first detached over California most likely holds the clue.

[Genghis the Engineer]

Question for those who know, 'cos I don't.

About ten years ago I found myself spending some time in Russia looking at Spacecraft systems, we covered re-entry technology.

The semi-spherical capsules built by the Russians (most notably Resurs and Soyuz) use a single piece moulded composite heat shield which ablates. and in the course of re-entry loses 10-20mm of thickness (for the unmanned Resurs capsules they actually re-use these once). Buran on the other hand, uses a form of thermal quilt, I believe using substances not chemically all that dissimilar to asbestos.

An obvious feature of both of these is that neither has or critical local attachments, which seem from most discussion to be the weak point on the Orbiter's system. So why did NASA go for this particular solution - is it because it's an obvious derivative of the system used on the Apollo capsules? NIH syndrome? Or were they genuinely convinced that it was the best solution available - in which case what are the faults in the Russian systems that I can't see?

G

[Wino]

Apollo had an ablative heat sheild, not the tiles like the shuttle.

The tiles were to be reusable quickly and it can be argued have worked quite well for 100+ missions.

Asbestos is very tough to use in the USA now with current regulations.

Furthermore the Buran only flew once so it is not really a good comparison as far as reusability is concerned. It would be intersting how many flights it would have flown before it blew up.

Cheers
Wino

[PickyPerkins]

According to this site (http://www.buran.ru/htm/molniya.htm) the Soviet Buran shuttle used similar materials and methods to the US Shuttle.

------- Start quote ---------
The gliding descent from the orbit through dense layers of atmosphere has stipulated the necessity to use a principally new reusable thermal protection system designed to sustain 100 flights. For the BURAN orbiter three kinds of thermal protection have been developed:

"carbon-carbon" material with maximum operating temperature up to 1650 degrees C for the components with the highest thermal load -the fuselage nose and wing leading edge,

ceramic tiles for parts heating up to 1250 degrees C,

flexible material for surface parts with the temperature not higher than 379 degrees C.
All of them surpassed by strength the materials used in the USA Space Shuttle construction.
------- End quote ---------

Question: How were the spherical spacecraft prevented from spinning on reentry initiated by random protrusions on their surfaces?

The unevenness might be there initially or develop as ablation proceeded. http://home.infi.net/~blueblue/_uimages/pi.gif

[PickyPerkins]

DrSyn posted a photo above which has been said (not by DrSyn) to show a “bite out of the wing”.

I may be trying to squeeze more out of this fuzzy photo than there is to be squeezed, but my impression is that it shows something projecting forward of the wing rather than something bitten out of it.

To make this easier to talk about, I took the image of the left-hand side of the a/c and flipped top-to-bottom, and drew in some vertical guide lines. I accept that the photo does not show a truly plan view. However, I think its near enough.

I think I see something projecting forward of the leading edge of the left wing in the flipped image. What do other people see?

The next two images are copies of the first two, but with more contrast. The last image is a superposition of images 2 and 3.

What could the projection be (if it is really there at all)? Is it a solid part of the orbiter? I assume not, but it might be. Could it be material being ablated off the wing? The atmosphere was very thin where it was photographed over New Mexico, at maybe 200,000 ft. Could ablated material move up-wind at all on a vehicle moving at more than Mach 20 in a VERY thin atmosphere? I have no idea.

Anybody have any relevant information or opinions?

http://home.infi.net/~blueblue/_uimages/compd.gif
http://home.infi.net/~blueblue/_uimages/compdd.gif

Note added 10th Feb. 2003
Looking at the video shot in Texas it seems obvious that ablated or burning material can and does move ahead of the solid material. So personally I now tend to believe the photo may show ablating material both ahead of and trailing behind the left wing.

This material seems to be in line or outboard of the undercarriage door area. As far as I can tell fron photos, the hinge of the doors are about in line with the change in angle of the leading edge of the wing, with the undercarriage well being inboard of the hinges.

Looking at the original photo posted above by DrSyn, the pixel size seems to me to be appreciably smaller that the size of the features under discussion. http://home.infi.net/~blueblue/_uimages/pi.gif

[Flash2001]

Some of the physics

Neither the mass nor the density of the object that fell off affect the total energy delivered to the structure. The relevant quantities are the area of the fragment presented to the slipstream, the dynamic unit pressure at the prevailing flight conditions and the distance between the point of detachment and the point of impact. From this must be subtracted the energy remaining in the fragments immediately after impact.

Assessing the potential for damage is far more difficult as it involves the area of impact and the strength and rigidity of both the fragment and the structure.

[atakacs]

Just catched this one:

Atlantis Adjusted Re-entry Fearing Damage (http://story.news.yahoo.com/news?tmpl=story&u=/ap/20030207/ap_on_sc/shuttle_safety_7)

Really wondering if it might have made a difference...

--alex

[Bubbette]

I heard (on the Batchelor and Alexander show) last night that the ex-Orlando Sentinel NASA beat reporter said after Challenger the whole nasa staff knew their was only a 12% that any shuttle would come down safely. If I find the link I'll post it.

[Dr Jekyll]

Has anyone access to any similar pictures of previous shuttle re entries? These could make it easier to judge what is a genuine anomaly and what is an artifact of the photograph.

[lomapaseo]

The asymetry between wings in the photos probably indicates that the wing is ragged or damaged.

However the detail can not be ascertained in a jpeg photo with low resolution such that the pixels are far bigger than the defect. with accompanied bleed over of black information into white pixels.

The good pictures available to NASA have not been published.

[atakacs]

Has anyone access to any similar pictures of previous shuttle re entries? These could make it easier to judge what is a genuine anomaly and what is an artifact of the photograph. You might try this link: STS96 (http://www.floridatoday.com/space/explore/manspace/shuttle/sts96/eom/irland01.jpg)

Which raises an interesting question: is the Starfire's image IR ? If so there should be some sort significant temperature gradations visible ?
If the Starfire's telescope is IR and caught the shuttle exposing previously unheated material, we would see
a different shade of black/gray or bright white/lesser white. :confused:

BTW: another picture worth mentioning (I guess): Average ascent picture (http://www.spaceflight.nasa.gov/gallery/images/shuttle/sts-107/html/jsc2003e06822.html)

--alex

[Genghis the Engineer]

(Quote)
I heard (on the Batchelor and Alexander show) last night that the ex-Orlando Sentinel NASA beat reporter said after Challenger the whole nasa staff knew their was only a 12% that any shuttle would come down safely. If I find the link I'll post it.

Whilst I've no doubt that you're quoting correctly, I think this is a rather libelous thing for anybody to say about a group of highly trained aerospace professionals. I don't for a moment believe that it is true - who in such a case would send people up. Also, the statistics simply don't bear out the point.



Re: Russian capsules. The apparently spherical shape is an illusion, the bottom is actually about the same shape as the Apollo capsules, it's just that the top continues round in something rather more resembling a sphere than NASA's preferred cone. I suspect the Russian system is rather more structurally elegant, but otherwise very similar. Small corrections were aerodynamic through built in combination of shape and CG (a bit like a weeble). Large corrections were via small motors in the apex I think - but this was really only for the earliest stage of re-entry.


Thanks for the correction about Buran heatshield. My work in Russia was mainly on Resurs with a bit of Soyuz so I'm probably just remembering the quilting as an example of alternative methods.

G

[PickyPerkins]

Rather than post again, I have added a note to my post of 9th February 2003. http://home.infi.net/~blueblue/_uimages/pi.gif

[sir]

PickyP

I have also had a play with this image. I traced the outline of the right (intact looking) wing, and flipped the outline onto the left (damaged looking) wing.

Then I wondered why it looks asymmetric - now could that be because this photo was taken when Columbia was making the left turn - at that point it was rolled 57' left, hence left wing down.

This does 2 things - it makes the fin (and any associated plasma trail) visible to the camera - which I believe is the trailing edge artefact, and may also make visible any plasma / hot flow above the wing to some extent.

Anyone know if there is a significant (ie visible) 'cloud' of plasma or material above the wing in normal re-entry ?



http://www.grafsnowboards.com/shuttle.jpg

The orange line is a symmetrical outline of the right wing (for reference).

Anyone got an opinion ?

[TheShadow]

Picky Perkins

Re the question you asked in your 09 Feb post:

"I think I see something projecting forward of the leading edge of the left wing in the flipped image. What do other people see?"

"Anybody have any relevant information or opinions?"




You may find the answer here (http://www.iasa-intl.com/folders/shuttle/flatplate.html) at this link (as supported by various emerging facts and the Pate-Cornell/Fishbeck 1994 Paper)

I do NOT think that it was anything to do with a "not quite overhead shot" or a banked attitude. In fact the damage discussed in the link may have propagated ALONG the LH leading edge by the time this shot was taken (60 secs prior to break-up)

TheShadow

[PickyPerkins]

I looked at the re-entry image of STS-96 which was linked to by atakacs.

It is remarkably symmetrical compared with the one image available for STS-107 Columbia, and has almost no trailing material. http://home.infi.net/~blueblue/_uimages/pi.gif

http://home.infi.net/~blueblue/_uimages/STS96.gif

[Rollingthunder]

In your image, with the centre line, the Shuttle looks asymetric from the tip of the nose to the end of the fuselage. That indicates to me that the shuttle was one wing high at the time.

[lamer]

Smackdown of the Shuttle Program written in 1980! (http://www.washingtonmonthly.com/features/2001/8004.easterbrook-fulltext.html)

Little did the author know he was being an optimist.

Regards.

[atakacs]

Yet another interresting picture (http://www.visi.com/~rolf/images/shuttle-overlay-perspective.jpg)

Not really conclusive, though...

--alex

[PickyPerkins]

atakacs
---------
This diagram (http://www.visi.com/~rolf/images/shuttle-overlay.jpg) from the same web site you linked to has the same illustration but also has some words with it which seem to make a lot of sense out of what we have been hearing about the ablation pattern and the sequence in which the sensors failed.

--- Quote from words on the diagram ----
... Wiring diagram shown is for the left wing. Scanners attached to the orange lines failed first, and six sensors on the main gear failed last.
----- End of quote -----------------------------

The orange wires take a 90º bend directly behind the leading edge of the wing where the sweep-back angle changes, shown in the NASA photo below of Columbia on the pad before launch of STS-107.

Of course, we should also remember the NASA warnings against jumping to conclusions which may turn out later to be wrong. http://home.infi.net/~blueblue/_uimages/pi.gif

http://home.infi.net/~blueblue/_uimages/wing.jpg

[cwatters]

One of the press releases covering the sequence of events says something like.... the onboard systems fired the thrusters when the elevons were unable to correct for the asymetric drag.

Out of interest, have the thrusters ever been fired before during this phase of flight or is this just a sign of how bad the situation really was?

[atakacs]

Some very interresting picts here:

http://www.eclipsetours.com/sat/index

The net is an amazing place...

--alex

[Flash2001]

CNN this morning showed exerpts from a NASA engineering memorandum suggesting that there would be a problem if the shuttle undercarriage didn't deploy when needed. In contained phrases like "Totally screwed up" and "World of hurt". Are these NASA engineering terms? Most engineering memoranda I have seen are a bit more technical. Are these the terms NASA engineers think in?

[rehkram]

It was an internal email apparently hence the informal language, see this story: Email warned of catastrophic failure (http://www.orlandosentinel.com/news/custom/space/orl-nasa-congress021203,0,1886968.story).

[DrSyn]

Regrettably, it now seems that the lo-res picture that has triggered so much debate in recent days really is all they took at Kirtland on that fateful morning - with a 3½" telescope and an "old" computer . . "in their free-time." Evidently, the precision elements of Starfire were not employed nor, indeed, requested. No comment.

Just to consolidate some of the plethora of references on this thread (please note download size before clicking!) here are links to the pdf (Acrobat) docs referred to - the big ones are for seriously interested folks only! (Shift+Left Click to view in a separate window) :

The emails mentioned by rehkram can be found here (http://www.nasa.gov/columbia/COL_landgear_email_030212.pdf) (192kb).
The original Paté-Cornell/Fishbeck paper - 1990 (http://spaceflight.nasa.gov/shuttle/investigation/tps_safety.pdf) (4.8mb).
The later Paté-Cornell/Fishbeck paper - 1994 (http://www.nasa.gov/formedia/MP_risk_tiles_1994.pdf) (2.9mb).

Ms Paté-Cornell has been reported as saying that she agrees with Ron Dittemore's remark about a "missing link" at an earlier briefing following the accident. It is also now being suggested that one sensor indicated "improper" left gear deployment, just before breakup, although two other sensors did not. Gear extension at that speed, if so, would undoubtedly be catastrophic and does not, in my personal opinion only, explain the progressive drag increase observed prior to the main event.

Below is a diagram of the left wing structure, which I hope helps to visualise the layout and what it all looks like under the Thermal Protection System (TPS). Note the short distance between the LE and the wheel well, around the point where the wing-sweep changes.
http://ourworld.compuserve.co.uk/DrSynHst/images/LWs.jpg
Enlargement (http://ourworld.compuserve.co.uk/DrSynHst/images/LW.jpg) .

This is taken from the earlier Ko-Fields Report Oct 1987 (http://www.dfrc.nasa.gov/DTRS/1987/PDF/H-1400.pdf) (1.3mb)

I remain inclined to believe that there may have been (also) a RCC LE panel contributing to the scenario. This would indeed be a formidable missing link. Picky's link of Columbia's LE (Page 10) clearly shows the grey RCC panels for those unfamiliar with the subject. Likewise, the video appears to show two separate pieces of debris falll from the ET at the 81-sec point during launch ---- two bits = two possible damage sites.

[Flash2001]

I read the whole email. 40 psi overpressure my foot!! What about the kinetic energy of the wheel fragments? I remember on an introductory course to the F101 that we were told that the most dangerous thing on the aircraft was not the nuclear weapons, but the tyres. It was phrased thus: Each wheel contains enough stored energy in compressed air and stretched nylon to put a golf ball into geosynchronous orbit.

[DrSyn]

Further to my last, this statement has been recently released:
----------------------------------------------------------------------------
Steve Nesbitt
Columbia Accident Investigation Board Feb. 13, 2003
(Phone: 713/301-9571)

RELEASE: 03-072

STATEMENT BY THE COLUMBIA ACCIDENT INVESTIGATION BOARD (Feb. 13, 2003)

Note: The CAIB has asked NASA for administrative support to release information to the public and the media. The following statement was provided by the CAIB for release.

Thermal Analysis Shows Hot Plasma Possible in Columbia Left Wheel Well Area

Preliminary analysis by a NASA working group this week indicates that the temperature indications seen in Columbia's left wheel well during entry would require the presence of plasma (super heated gas surrounding the orbiter during re-entry).

Heat transfer through the structure as from a missing tile would not be sufficient to cause the temperature indications seen in the last minutes of flight. Additional analysis is underway, looking at various scenarios in which a breach of some type, allowing plasma into the wheel well area or elsewhere in the wing, could occur.

Other flight data including gear position indicators and drag information does not support the scenario of an early deployment of the left gear.

The search continues for possible debris from Columbia in the western U.S., but as of early Thursday, no debris further west than Ft. Worth, Texas has been confirmed as Shuttle-related.
------------------------------------------------------------------------------
I refer to my (and others') earlier remarks on RCC sections.

[rehkram]

Here is a NASA plain english overview of RCC (reinforced carbon-carbon) panel manufacture, fixings and usage on the wing leading edge:
http://spaceflight.nasa.gov/shuttle/reference/shutref/orbiter/tps/carbon.html
The RCC panels are mechanically attached to the wing with a series of floating joints to reduce loading on the panels caused by wing deflections. The seal between each wing leading edge panel is referred to as a T-seal. The T-seals allow for lateral motion and thermal expansion differences between the RCC and the orbiter wing. In addition, they prevent the direct flow of hot boundary layer gases into the wing leading edge cavity during entry. The T-seals are constructed of RCC.

Plus some coherent reporting on the exact sequence of events, contains some information I'd not seen before:
http://sfgate.com/cgi-bin/article.cgi?f=/c/a/2003/02/14/MN226524.DTL
Seconds after this final, abortive communication, two of the shuttle's right-side jets fired to help keep the craft in the right flight orientation, and the elevon motions grew, the left one moving upward by 8.11 degrees.

A second later, all data and communications disappeared.

[PickyPerkins]

atakacs wrote: Some very interresting picts here: http://www.eclipsetours.com/sat/index The net is an amzing place...
-----------------------------------------------------------------------

Apparently too interesting. The picts have been removed. http://home.infi.net/~blueblue/_uimages/pi.gif

[ivan]

Foot search continues in Albuquerque, New Mexico today for a desk sized pice of shuttle that was tracked by radar as it fell into the Sandia Mountains East of Albuquerque. USAF helicopter search of the area on Thurs yielded nothing, but the search was instigated after a local woman found a confirmed piece of the shuttle on Thurs morning.

Albuquerque is some distance away from the main crash area in Texas, and the shuttle was viewed as it passed overhead to be reasonably intact (ie no distinct trails in the sky).

[PickyPerkins]

A report (http://www.kmsb.com/special/021303dnnatbreakup.a3ab9.html) says that early analysis of low-frequency infrasound data sound-wave recordings suggests that the space shuttle Columbia depressurized and blew apart in a single explosion near Lubbock, Texas.

The report says that a preliminary analysis was posted earlier this week on a Southern Methodist University (SMU) web site and then removed. NASA has impounded the information, along with similar recordings from other infrasound stations in the western United States.

Infrasound is low-frequency sound, waves at 20 hertz or lower – just below the threshold of human hearing. The report said that it took about 30 minutes for the sound waves to travel the distance from the shuttle to the infrasound array near Lajitas in the Big Bend region, and to another in Nevada.

I believe the main purpose of the infrsound network is to plot lightning strikes over the entire USA. http://home.infi.net/~blueblue/_uimages/pi.gif

[OVERTALK]

Picky

TRY
this link (http://www.iasa-intl.com/folders/shuttle/GoodbyeColumbia-2.html)

[ORAC]

Associated Press
HOUSTON -- The board investigating the space shuttle Columbia disaster Saturday toured the Louisiana plant where the orbiter's external fuel tank was built, while searchers scouring the mountains of New Mexico -- west of where any debris has been found -- were coming up empty.

Investigators also revealed that two more Columbia control jets, making at least four in all, continued to fire in a desperate attempt to stabilize the shuttle during its final minutes.

The jets fire automatically when flaps on the shuttle's wings and tail are inadequate to control abnormal motions encountered at supersonic speeds. The information was coaxed from the final 32 seconds of ragged data sent from Columbia as it was breaking apart, investigators said.

The last voice communication from the shuttle's seven astronauts came as Columbia streaked across New Mexico during reentry Feb. 1 before breaking apart about two minutes later.

People near New Mexico's Sandia Mountains, east of Albuquerque, reported hearing a whooshing sound, said Peter Olson, a spokesman for the New Mexico Department of Public Safety. He said there also was radar evidence that debris could have fallen in the state, but he didn't have details.

About 140 searchers concentrated Saturday on a rugged 2-square-mile area of Embudito Canyon, walking a few feet apart. Nothing was found as teams began wrapping up by afternoon; one searcher picked up a small disc of melted metal that was later identified as part of a beer can. Two helicopters from White Sands Missile Range that criss-crossed the area also came up empty.

The Embudito Canyon search was expected to last only a day, but NASA could search elsewhere in the state, officials said.........

[OVERTALK]

It is becoming apparent that the genesis of this Shuttle accident was not unlike that of the Challenger....too many people (who should have known better) disregarding the environmentals pre-launch.

It has been admitted that the Columbia sat on its launch pad much longer than any other Shuttle before it (39 days) and that the weather was the coldest Florida weather for over 50 years. I recall seeing deep snow on the TV at the time. That's a lot of freeze/melt/re-freeze cycles for the foam insulation - which undoubtedly as a result was rain-soaked, freeze-cracked and was ready to separate in large icy spear-like stalactites under the stresses of max Q (81 secs into launch). Of course, once the liquid hydrogen was loaded, the foam was then frozen in place. It took the post-launch thermodynamic heating to thaw it and it then separated along its cyclic fault-lines. If you look here (link) (http://www.iasa.com.au/folders/Safety_Issues/RiskManagement/rcc-1.html) you will see that it has happened before and damaged the RCC leading edge in a similar fashion to what is here (http://www.iasa-intl.com/folders/shuttle/flatplate.html) suggested may have happened to STS-107.Once you read into the NASA specifications for the RCC leading edge, it becomes apparent that it was "toughened" - but only against high temperatures (as part of the TPS) - and never against IMPACT. They never took the required precautions against launch debris impact - probably because the spec for its "raison d'etre" was always to revolve around its resistance to re-entry heating.

A likely fix would be to affix a vulcanized sacrificial strip along the RCC Leading Edge (even a non-aerodynamic and deflective one). That reasonably practical fix would provide launch debris impact protection yet quickly burn away on re-entry. A pointy impact of an icy stalactite on that RCC L.E. probably did what you would expect any pointy impact to do to what's essentially nothing more than a toughened graphite, i.e. shatter it. Because it is only "bolted on" (via inconel attachments), loss of its structural integrity (by shattering) would have led to it being rapidly eroded away. But how?

If you read the NASA blurb here (http://www.iasa.com.au/folders/Safety_Issues/RiskManagement/rcc-1.html), they describe it as being critically coating-protected against oxidization. Once an RCC section was shattered on launch, that section’s oxidization destruction on re-entry was assured. Unfortunately that section was right ahead of the port wheel-well’s outboard forward corner. Superheated white-hot RCC pieces detaching was what the Owens Valley Astronomer would have seen in the pre-dawn darkness. The underlying aluminium wing surface is only rated to 175 odd degrees. No wonder the wheel-well was pierced and the events in there set in train (see ]here (http://www.iasa.com.au/folders/Safety_Issues/RiskManagement/superhotair-1.html) and here (http://www.iasa.com.au/folders/Safety_Issues/RiskManagement/superhotair.html).

Further Reading on the Thermal Protection System is here (http://spaceflight.nasa.gov/shuttle/reference/shutref/orbiter/tps/).

This is an excerpt from the most recent set of modifications made to the Shuttle Fleet. I obtained these documents just prior to NASA pulling all information about the shuttle from the net on that fateful Saturday. Read carefully.

" The area aft of the reinforced carbon-carbon nose cap to the nose landing gear doors has sustained damage (tile slumping) during flight operations from impact during ascent and overheating during re-entry. This area, which previously was covered with high-temperature reusable surface insulation tiles, will now be covered with reinforced carbon-carbon.
The low-temperature thermal protection system tiles on Columbia's midbody, payload bay doors and vertical tail were replaced with advanced flexible reusable surface insulation blankets.
Because of evidence of plasma flow on the lower wing trailing edge and elevon leading edge tiles (wing/elevon cove) at the outboard elevon tip and inboard elevon, the low-temperature tiles are being replaced with fibrous refractory composite insulation (FRCI-12) and high-temperature (HRSI-22) tiles along with gap fillers on Discovery and Atlantis. On Columbia only gap fillers are installed in this area."

[atakacs]

From the Albuquerque Journal a picture of the system used by the "Starfire geeks":

http://www.abqjournal.com/pix/020903_week/scope02-13-03.jpg

and a close-up from AP: (http://www.stargazing.com/photos/shuttle-pic-setup.jpg)

They used a Questar 3.5" telescope on a fixed tripod and the tracking
mirror (which is a flat mirror and a high-precision pointing stage) to
point. They started putting things together the evening before, just
on a lark.

"They mounted [the Questar] in front of a set of larger movable
satellite-tracking mirrors that had been salvaged from White Sands
Missile Range two decades ago.

"Old but still reliable, the mirrors tracked the shuttle, reflecting
its image back to an instrument room where the telescope was mounted."

...emerged from clouds...to clouds...24 seconds...only time to snap one
picture...36 degrees above the western horizon, nearly 70 miles away at
the time.
Not quite sure to understand what we are looking at.

The camera or whatever was attached to the scope is definitely not consumer
grade , no camcorder or webcam . There are other gizmos in the image which
look professional. Does anyone know any of these pieces of equipment?

Edited to remove that huge picture that ruins all the formatting of the thread. If you want to use a picture that is larger than the normal screen size the just post a link to the page with the picture instead of the picture itself! :*

Sorry about that - won't happen again !

[whitehat]

atakacs, mate. I think they've established that Starfire isn't going to provide any great answers.

Any chance of doing something about that darned great photo? It's a bit of a screenful!

[RobertS975]

A protective leading edge material designed to burn away on re-entry is an excellent idea but there must be a way of jettisoning the non-aerodynamic protective material in the event that orbit is not achieved and the shuttle either does a return to KFC or lands at one of the contingency strips in Rota, Spain or Dakar, Senegal.

[arcniz]

When in doubt, launch another project:


www.denverpost.com/Stories/0,1413,36%257E33%257E1185329,00.html (http://www.denverpost.com/Stories/0,1413,36%257E33%257E1185329,00.html)

[DrSyn]

arcniz, someone at the top is finally waking up to reality, just like they did after Challenger. Then, they realised that the ELV program was almost non-existent and took steps to rectify it. Now, they find that only three Orbiters remain to look after the ISS/HST and other great investments. Aviation is not isolated from the rest of history in repeating itself every so often. The politicians see to that!

OVERTALK's sacrificial strip is an interesting concept. I feel, however, that preventing bits falling off the ET during launch might have first priority, as the TPS has worked satisfactorily on 111 occasions and has been upgraded in the light of operational experience.

On the question of ET ice, I remain doubtful. It was not a cold day and those who were around the stack prior to launch say that there was no visible ice present on the tank. Also, OT, the ET coating is weatherproof and, theoretically cannot soak up water. I understand that there were no signs of cracked foam on launch day. However, the thermal cycles you mention are valid. What if micro-cracks evolved that were not easily visible but let in some moisture?

Ice has always been an issue on the ET, but large chunks of foam falling off has not, until STS-112/107. There may be other issues here, perhaps the earlier redesign of the foam to eliminate CFCs, for example. I hate to raise it, but QC has to be considered too. As I said on an earlier post, without the ice, one 2.5lb mass (or two!) striking at just the wrong angle, at that speed, is quite a whack.

With all the descriptives flying around about the RCC sections (my favoured theory) I thought it might help to post a diagram which illustrates the RCC attachment system. This is from the Curry/Johnson presentation (http://www.futureshuttle.com/conference/ThermalProtectionSystem/Curry_73099.pdf) (pdf 900kb) at the Future Space Shuttle Conference 1999. The enlargement also shows the later mod and a T-seal. To my mind, the (flexible) T-seals are one feature that would not enjoy being whacked and could let in a lot of plasma, initially in a metered manner.

http://ourworld.compuserve.co.uk/DrSynHst/images/RCC-XS.jpg
Enlargement (http://ourworld.compuserve.co.uk/DrSynHst/images/RCC-XSL.jpg)

As mentioned elsewhere, if plasma gets past, or through, an RCC panel, how long would it take to reach past the secondary protection and on to the alluminium attach points? Where it goes thence is largely academic - but surely a "bad day."

[OVERTALK]

DrSyn
It may be the case that the ET foam is water-proof but it would only take a minor imperfection to allow water to infiltrate and affect the adhesive over 39 days of rainy freeze/thaw/re-freeze (mechanism for that described below). A large section of iced foam might detach not only because of degraded adhesive but because of the weight of water behind it. But there is a further factor - when you're talking about a cryogenic fuel-load.

"It was not a cold day and those who were around the stack prior to launch say that there was no visible ice present on the tank." Any poorly adherent foam section would look like any other but once the External Tank is fuelled with liquid hydrogen (at minus 250deg F), I understand that it is one large icicle. But you have to further consider that any water infiltrating behind the foam is not just ice, it is super-cooled and will contract quickly and mightily. That almighty contraction would suck in the surrounding foam - forming a circumferential crack (albeit one that may not be visible and may be initially only in the adhesive substrate - but that's where it counts). That crack then delineates the piece that will/could later detach. At max Q I would guess that there are areas of lower pressure around the ET (i.e. where the airflow sucks). Once thermodynamic heating reduces the adhesive quality of the ice itself behind that flawed section of increased weight foam (like hand-warming an ice-tray) that flawed section is free to detach (but it's still an icicle in stalactite form).

Even though the external tank's cladding may be tested waterproof where it's made, transportation, erection and attachment stresses on the empty vehicle may well compromise the water-proofing of the foam cladding on that flimsy, empty (and therefore flexible) tank. The solution may be to simply give it a good ScotchGuarding spray top-to-bottom once it is in the launch position.

But as further insurance, a sacrificial rubbery L.E. wedge (aka false leading-edge) on the Orbiter's wing would easily deflect any such stalactite and burn away early on re-entry. I will be surprised if they don't go for this as a fix.

OVERTALK

[DrSyn]

I don't dispute the idea of moisture getting behind the scenes, OT - that was behind my point about possible "micro"-cracks. You've expanded the point quite well, however :) The scenario has been revisited by the Board over the past few days, and I am sure you've been following it as closely as I.

The subject is being eruditely discussed elsewhere, and by some who are or were actively involved in the program. As there has been no further interest in this thread in past days, there seems little point in continuing it here. I'll conclude with a couple of recent quotes which I thought were interesting:

"NASA believes the piece of insulating foam detached from a section of the external fuel tank called the bipod. In addition to sprayed-on polyurethane foam, portions of the bipod and other parts of the tank exposed to the highest temperatures also are treated with a silicon-based substance called Super Lightweight Ablator. The concern is whether that material under the foam also broke lose from the giant aluminum tank, which might have added considerable heft to a piece of foam originally calculated to weigh 2.67 pounds."

". . . . Was it ablative material behind the foam? Was it metal behind the foam or was it ice?"

As it should, the investigation is maintaining a wide perspective.

[DrSyn]

Indeed, this article (http://www.centredaily.com/mld/centredaily/news/5224175.htm) highlights just how a potential weak link in the chain of the otherwise well-sealed ET TPS might allow moisture into the system - especially with prolonged weathering. Interesting reading.

[OVERTALK]

RobertS975

You have to work out a risk-management philosophy that's weighted toward the the greater threat (launch debris damage or launch abort).

a. Engine failure aborts, if some engine power/thrust remained, the Orbiter's aerodynamics wouldn't be degraded unrealistically by a wedge-shaped protective inboard leading edge. Many jet aircraft sport those for improved spin-stall characteristics. You'd probably only need about two metres per side in order to protect the very vulnerable areas of the wheel-well in particular. The remaining outboard span's protective sacrificial overlay could be a conformal section (not wedge-shaped deflective).

b. Alternatively, for the highly vulnerable inboard areas, a jettisonable false section similar to a fillet could be fitted. An in-atmosphere emergency jettison of that could be as simple as an explosive bolt each side at its leading fuselage attachment point. In the event of an abort they'd peel away with the ET and SRB's. For re-entry, it would be pre-jettisoned (or it could simply depart by design with the ET or SRB's, its protective role being superfluous by then).

It's not really rocket science, it's just a matter of protecting what demonstrably post-Columbia needs to be protected / needed to restore confidence / is required to avoid the necessity for complex in-orbit inspections.

[atakacs]

From space.com article (http://www.space.com/missionlaunches/sts107_nevada_030223.html)


A NASA official told searchers that the hilly desert and knee-high sagebrush near the Nevada-Utah state line may contain a six-foot chunk of landing gear, said Bob Williams, a Lincoln County sheriff's volunteer and a spokesman for the Nevada search effort.

On what basis ?!

Strikes me as really odd

--alex

[PickyPerkins]

I imagine the searches on the Nevada-Utah state line are being made on the basis of radar returns, and that some guesses about what to look for have been made based on the trajectories of the debris. Maybe they are looking for a main gear door rather than for the main gear itself. The door could be about six feet long and might have fluttered down.

Seems that some people who should know are still not entirely happy with the composition of the inquiry board and its reporting responsibilities:
---- Start quote -------
.... "It would put their independence beyond a doubt if they were to report to the president," said David C. Acheson, a member of the Challenger board. Acheson, 81, a retired attorney living in Washington, was one of the 13 members of the Rogers Commission, named after its chairman, the late William P. Rogers, the former Secretary of State. ......The Rogers Commission was made up of engineers, an astronomer, a lawyer, a space journalist, Nobel Prize-winning physicist Richard Feynman, former astronauts Neil Armstrong and Sally Ride and legendary test pilot Chuck Yeager. Its unsparing 1986 report on the Challenger accident pushed NASA to make significant safety and management changes to the space shuttle program. .... "I think one of the big differences is we had several serious scientists on the board," said Eugene Covert, 77, an engineering professor at MIT and Rogers Commission member. "I don't think there are any serious scientists right now." .......
---- End quote -------
http://customwire.ap.org/dynamic/stories/S/SHUTTLE_TWO_BOARDS?SITE=NHCON&SECTION=HOME&TEMPLATE=DEFAULT

Note added Feb 25 2003
From: http://www.spaceflightnow.com/shuttle/sts107/030220pinpoint/

------- Start quote ---------
Video imagery of Columbia's entry provided to NASA was analyzed by imagery, trajectory and ballistics experts," the release said. "The results of that analysis were then provided to National Transportation Safety Board officials who reviewed air traffic control radar imagery in that area during the time of Columbia's descent.

"The review resulted in what is believed to be a significant radar track of a piece of debris as it fell to Earth. As a result, a search of the Caliente area near the Nevada-Utah border is under way using Civil Air Patrol assets. A search using additional means also may be forthcoming."
--------- End quote --------

http://home.infi.net/~blueblue/_uimages/pi.gif

[ORAC]

An upper wing heat shield tile has been recovered in west Texas. It shows extreme heat damage, much more than can normally be expected during re-entry.

CNN (http://www.cnn.com/2003/TECH/space/02/25/sprj.colu.debris/index.html)

[PickyPerkins]

Can someone please explain to me about the wing roughness of the Columbia?

I have seen a roughness of 0.1-0.2 inches is being talked about.

Is this a waviness in the wing surface, or what?

The metal wing itself is presumably accurate and made according to drawings to within a few thousandths of an inch, so was not rough (in the sense of deviating from the intended contour) at all.

The tiles are computer designed and cut (is this right?) so that they are also presumably accurate in shape and thickness, and also made according to drawings to within a few thousandths of an inch.

I take it that the tiles themselves are not rough, and that the problem is not in the tiles themselves, since all Shuttles have tiles but only Columbia has been said to suffer from excessive wing roughness.

So how does roughness arise, what does it consist of, and what causes it?

Is it something which could have been worked on during one of Columbia’s three 12 mth long re-fits at Palmdale?

Did these re-fits include complete re-tiling?

http://home.infi.net/~blueblue/_uimages/pi.gif

[ORAC]

Wing Roughness (http://www.rense.com/general34/brek.htm).

The comments about turbulent flow are interesting when put together with the state of the upper wing tile found in west Texas.

"Normally the shuttle's wings transition from laminar to turbulent flow at 1,200 seconds into re-entry, Gibson said. "On STS-28, on Columbia, that transition happened at 900 seconds -- 300 seconds early. As you might expect, the left wing saw a significantly higher heating environment than the rest of the orbiter."

[PickyPerkins]

Thanks for the link, ORAC

The article you link to says:
-------- Start quote ---------
… Even with replacements over the years, 70 percent of Columbia's tiles were the originals… Surface roughness ……. has to do with the gaps between the shuttle tiles and the "step," or difference in height, between one tile and its neighbor. …….The roughness of the wing is indicated by a measurement called the K equivalent, derived by combining data on the gaps and steps with information on the airflow …
-------- End quote ---------

The impression I get now is that the roughness is a left-over of the tile-installation learning curve from 20+ years ago. In that case, there may be nothing wrong with either the tiles or the wing, just that the installation methods had not yet been developed sufficiently when the first Shuttle was built. I wonder if the left wing was built first?

One might guess that if tiles projected various distances due to imperfect installation, then the adhesion in some cases might not have been too good either. http://home.infi.net/~blueblue/_uimages/pi.gif

[sir]

Picky

Isn't that picture dated 1979 ? - there's a caption in the folder above.

Presumably that picutre was taken during construction or something ??

[PickyPerkins]

sir

Thanks for the correction. The Columbia was not launched until 1981, so if the photo was made in 1979 it must show it in its “as made” condition. I will edit my post above to delete the photo.
------------------------------------------
03/12/79 Overland transport from Palmdale to Edwards
03/20/79 SCA Ferry Flight from DFRF to Bigs AFB, Texas
03/22/79 SCA Ferry flight from Bigs AFB to Kelly AFB, Texas
03/24/79 SCA Ferry flight from Kelly AFB to Eglin AFB, Florida
03/24/79 SCA Ferry flight from Eglin, AFB to KSC
11/03/79 Auxiliary Power Unit hot fire tests, OPF KSC
12/16/79 Orbiter integrated test start, KSC
01/14/80 Orbiter integrated test complete, KSC
02/20/81 Flight Readiness Firing
04/12/81 First Flight (STS-1)
-----------------------------------------------

Note added later
After some further digging I find that the photo was taken on March 25, 1979, the day after Columbia arrived at KSC for the first time after its delivery flight from California.

http://home.infi.net/~blueblue/_uimages/pi.gif

[OVERTALK]

>JBS said:
>"I read today they say it
>localized to four panels on the leading edge of left wing."
>
>JBS
Haven't been able to find this anywhere. Do you have a URL??


However, in response, my theory about the "flat-plate effect" (http://www.iasa-intl.com/folders/shuttle/flatplate.html) of losing a section of the RCC leading edge is so far supported by all that's been declared or noted (and borne out well by the info in the links below):
_
a. The reinforced carbon-carbon (RCC) is vulnerable to impact-shattering - by (say) the pointy impact of an icy stalactite from the detached tank foam and its two underlays (the substrate that supposedly has no purpose and above which is the ablative layer, more adhesive and foam). Why did the foam (and its sub-layers) separate and why would it be hard and icy? Well supposedly the Columbia was on launch-pad 39A for 38 days, longer than any other shuttle before it. It sat through some of the coldest sub-zero weather in Florida's recorded history. All the freeze/thaw/refreeze cycles would have allowed water to get beneath the external tank's foam adhesive and loosen it (as well as cracking sections circumferentially – it’s called cryo-pumping – see Link 3 below). At launch the water beneath the foam would have been adhesive ice (because of the liquid hydrogen) – but later, at that 81 second point it would have had enough aerodynamic heating and lift-suction to have melted that ice (and the ET's icy hydrogen fuel would have been emptying quickly to well below that high-up point anyway).
_
b._ Once impacted (by a hard pointy object) the RCC on the Orbiter’s Wing Leading Edge would shatter and then (no longer being a solid integral mass) lose its retention by that section’s inconel bracket and also lose the integrity of its impermeable top layer of silicon carbide and tetraethyl orthosilicate (that protects it against oxidization on re-entry).
_
c._ Reportedly a small object was radar-detected in orbit floating near the Shuttle. My theory has this as a sizeable segment of that RCC section that was shattered (and located just forward of the outboard corner of the wheelwell). Why would it have separated? As the Shuttle orbits it is subjected to intense heat and then cold and eventually all those expansion/contraction cycles would allow a shattered segment to work free and float off under any light manoeuvre.
_
d._______ Upon re-entry, because of the loss of solidity in that RCC section (plus a sizeable missing segment) the remaining shattered RCC pieces would have been quickly oxidized and detached. That was the pre-dawn fiery sparking seen by the Owens Valley astronomers (and others). At that point there remains only the Inconel 718 bracket and the flat-plate aluminium leading edge – before the wheelwell is broached. Because of the flat-plate effect, localized extremely high plasma temperatures, far in excess of those ever before seen on re-entry, would be generated and that superheated plasma bubble would create the distinctive extension well ahead of that inboard wing [as seen in the Air Force telephoto as a protuberance]. Of course at the same time that aluminium flat-plate would be melting and allowing ever-increasing amounts of that superheated plasma into the wheel-well. Evidence for this?
_
e._______ Dittmore said that some recovered left wing tiles exhibited heat damage “that was not caused by re-entry heating”. In addition there were embedded orange beads within the over-heated areas of those tiles. My theory is that those beads will prove to be an oxide of one of the constituent metals in the Inconel RCC support bracket.
______ _
Solutions?
1._ Shuttle crews have already flight-tested miniature robot cameras for in orbit inspection. See link here (http://www.space.com/businesstechnology/technology/nasa_robots_030209.html)
_
2._ A two-part mix layer of an Araldite-like epoxy-based ablative substance could be overlaid across a damaged section (including the LE) and exothermically set itself in place. If thick enough, it should last out a "once off" re-entry (and be within the controllability of the lateral controls – or a similar patch applied to the other wing for symmetry). Once damage is evident, to achieve this “patching” an EVA astronaut would require a couple of LE overcentre-locking clamps (i.e. with long handles to get back above and below the LE) and an LE cable between them (for his positioning and leverage and to hold the 2 clamps together). The clamps would be affixed and later removed whilst he is tethered and manoeuvring with a jet-pack. This is not rocket-science.

_3. It might be possible to affix a sacrificial wedge-shaped launch leading-edge that would protect those inboard areas near the wheel-wells, in a protective profile that would be acceptable aerodynamically for a launch abort - and yet quickly burn away on re-entry. Silicon rubber springs to mind as a suitable protective medium.

A._ Link (http://www.iasa.com.au/folders/Safety_Issues/RiskManagement/rcc-1.html)__ What is RCC?
_
B._ Link (http://www.iasa.com.au/folders/Safety_Issues/RiskManagement/moreshuttlespec-3.html)__ A Leading edge breach is chief candidate.
_
C._ Link (http://www.iasa.com.au/folders/Safety_Issues/RiskManagement/STS107ExtTankREvelations.html)__ The External Tank and its Foam
_

[sir]

NASA have released a 13 minute video shot inside the orbiter by the crew, during re-entry of Columbia, and ending 11 minutes before the loss of communication with the orbiter.

Video (Real Media) (http://198.116.66.254:8080/ramgen/hq/sts107/sts107.rm)

and some images (http://spaceflight.nasa.gov/shuttle/investigation/amos/index.html) of Columbia in orbit, 4 days into the mission, photographed from the AMOS system in Hawaii.

None of these pictures show the left wing leading edge area, although the right wing leading edge is clearly visible.

Surely some images showing the left wing were captured too ? I wonder if they will be released.

[PickyPerkins]

This photo of the left wing has been published. Sorry, I can't remember where I saw it. I think it was taken on about the 4th day of the flight. The photo seems to show no visible damage.

Note added on March 5, 2003
The photo referred to above was taken during orbit 5 on flight day 1 and is the 8th photo here (http://www.caib.us/news/photos/index.html).
http://home.infi.net/~blueblue/_uimages/pi.gif

[sir]

hmmm.....

cheers Picky,

I was also looking for a pic which shows the leading edge root extension / fillet section - the part where the wing leading edge sweep angle changes. I guess this is probably not visible from inside the orbiter.

[DrSyn]

I am glad that a few continue to show concern for this historic accident. Some interesting points raised by OT. I remain convinced, however, that the foam alone (now officially 3 pieces) was capable of doing the necessary damage, with or without added ice. I also believe that any ice involved was no more than subliminal but could indeed have precipitated debonding of the foam, for reasons already stated. sir, there are no known pics of that section of the LE, sadly.

There have been many previous significant hits on the TPS from foam, and well documented. I am inclined to believe that Columbia's TPS took at least two hits which damaged different sections of the heat shield, thus making the "back-tracking" of the break up sequence more difficult for the investigators. The RCC area still makes by far the most disasterous likelihood, with the possibility that any tile damage alone might have been survivable. But where was the RCC breached?

The original theories are holding up uncannily well. NASA provides a comprehensive tile pattern diagram here (http://spaceflight.nasa.gov/shuttle/reference/sodb/2-5b.pdf) (PDF 337kb), which can be expanded in good detail. I am told it is quite accurate by those in the know. They also released a significant photo (http://www.caib.us/images/photos/download/STS-107-left_wing_underside.jpg) of a recovered portion of the left wing. Whilst I have no doubt that someone already knows exactly where it came from, I have found no official reference (OK, tell me I missed it).

Anyway, having mucked about with it for a while, it seems to me that it is from just inboard of the forward edge of the left wheel well. The blue outlines represent my efforts, whilst the yellow segment is an alternative theory doing the rounds elsewhere. If anyone can spot an elongated trapezoid like the one centre left (lower pics), with similar surrounding patterns, feel free to contradict - I'm not proud!
http://ourworld.compuserve.co.uk/DrSynHst/images/WL107.jpg
Note that the bare metal at the bottom of the picture has a smooth edge, as if it were cut by a torch. Not symptomatic of a break, or split.

So the questions are, just how many breaches in the TPS were there? Did the "spray" evident in the launch photos include significant "tile dust"? Answers on a post . . . please.

[PickyPerkins]

DrSyn Your analysis agrees exactly with the caption here (http://www.caib.us/news/photos/index.html) of the photo, which reads:
--- Start quote ----
Piece of STS-107 left wing underside, forward and inboard of the corner of the left main landing gear door. Delivered to Barksdale Air Force Base on February 7, 2003.
--- End of quote ----

Cheers, http://home.infi.net/~blueblue/_uimages/pi.gif

[DrSyn]

Thanks for that, Picky, I must have walked right past that caption on my way to the big picture (duh, on my part!). Anyway it adds an interesting dimension, as the "smooth edge" is actually inboard of the wing bulkhead and under the lower fuselage. Was there a burn-through from the wheel-well, or down the inboard RCC "tunnel", or was the TPS also damaged further inboard than just the wing area? It does tend to support the multiple-damage theory, in my view.

Here are a couple of views highlighting the location of that section:
http://ourworld.compuserve.co.uk/DrSynHst/images/WW3D.jpghttp://ourworld.compuserve.co.uk/DrSynHst/images/WWA.jpg
Further thoughts, anyone?

Addendum: This article (http://www.chron.com/cs/CDA/story.hts/space/1809873) in today's Houston Chronicle is worth a read. Must dash - another early start coming up :(

[PickyPerkins]

A question just so that I can be sure that I understand your left-hand drawing and to avoid confusion.

Shouldn't the center of the red ellipse be placed about one minor diameter lower than shown, so as to to be positioned around the corner where the front in-board lower edges of the wheel well meet?

Cheers, http://home.infi.net/~blueblue/_uimages/pi.gif

[DrSyn]

Yes, it was a bit "off", Picky. Now revised to be more illustrative!

[DrSyn]

There is a plethora of information on the web relating to the cause of this accident, some of it rather poor. As is usual, the official sources tend to be rather slow in updating. Some of the most erudite and current info is being supplied by a few of the US press sites, presumably "close to sources". I thought it would be helpful to those interested if I posted links to the ones that appear to have an educated grasp of the disaster.

Houston Chronicle (http://www.chron.com/content/chronicle/special/03/columbia/index.html)

This site seems to pick up on the latest developments rather well and in good detail. Further to my earlier post, they published an update (http://www.chron.com/cs/CDA/story.hts/space/1810935) (ex- LA Times!) on the possible RCC theory yesterday evening, which places possible damage right up at sections 1/2.

Orlando Sentinel (http://www.orlandosentinel.com/news/custom/space/orl-columbia-investigation.storygallery)

Not quite as prolific as the Hou Chron but well informed. In particular, they published some excellent graphics (http://www.orlandosentinel.com/news/custom/space/orl-columbia-graphics.photogallery) in the first weeks, which provide some splendid pictures of the structures that have been discussed on this thread. A must for pilots who find text descriptions tedious to fathom! Some talented artists there, among which the name Ingrid Pecca seems to feature often.

An interesting article (http://www.orlandosentinel.com/news/custom/space/orl-asecnasa07030703mar07,0,3829960.story) relates to safety recommendations that are already being looked at. Relevant to OVERTALK's earlier post.

CBS News (http://cbsnews.cbs.com/network/news/space/current.html#SRH)

This site contains some excellent articles and seems to be on the ball all the way. Worth monitoring.
--------------------------------------------------------------

I won't mention those that might have been expected to be at the front, but have rather lost their impetus recently. There is a surprising lack of currency at certain sites which are normally as close to the action as it gets :(

I hope this is helpful to Space-PPRuNers. Please post any others you think useful.

[BOAC]

UK television (Channel 4 - yuk!) are broadcasting something like 'Should it have launched?' this Saturday - 2000Z I think.

[OVERTALK]

It would appear that the much earlier speculation on these pages about the cause and effect is now being borne out by CAIB conclusions. However there are still some areas that they've yet to reach:

a. A sacrificial silicone-based elastomeric wedge-shaped leading edge for the inboard areas of the Orbiter's wings that would protect the easily shatterable RCC sections from launch debris strikes. This covering would burn off in the early stages of re-entry and being a simple wedge-shape, would not unduly affect shuttle performance during an in atmosphere launch abort.

b. The solution to in situ in orbit repairs. The two long-handled over-centre locking clamps for mounting a (say) 15ft cable along the leading edge and enabling an EVA astronaut to apply a two part exothermic one-time repair patch.

c. The projection ahead of the inboard left wing leading edge shown in the Starfire Photo is obviously due to the super-heated plasma and the flat-plate effect (http://www.iasa-intl.com/folders/shuttle/flatplate.html) (and here (http://www.iasa.com.au/folders/Safety_Issues/RiskManagement/flatplate-2.html)). This is something that NASA is yet to come to terms with. (quote: "The theory is also supported by a photograph taken by astronomers in Albuquerque, N.M., showing what appears to be a damaged, jagged area of the left wing.")

d. It is only a short step from here (this quote) to relating the super-heated plasma to the flat-plate effect (http://www.iasa-intl.com/folders/shuttle/flatplate.html).
"The leading edge theory is supported by several other pieces of evidence. Recovered leading edge panels now at Kennedy Space Center in Florida show that the attachment points were melted, rather than broken." and
"The wing was being eaten from the inside out," board member Roger Tetrault said. Similarly, investigators cannot explain why a piece of the left wing that adjoined the wheel well shows signs that a stream of hot gas had spewed out of the wing. Obviously the superheated plasma was entering forcefully at the leading edge RCC breach. Entry elsewhere would not explain the jagged projection ahead of the inboard L.E. or the "eating out" of the wheel-well interior....or the molten aluminium that was latterly being sprayed over the Shuttle's exterior by the plasma cloud (and embedded in the leading edges of non RCC tiles)

e. From the Washington Post Sunday 23 Feb 03 [page A20] "A worst-case analysis by Boeing Co engineers of the potential damage caused by the tank insulation estimated that the material could have hit the wing at more than 400mph and could have included pieces of ice which would have done more damage than the foam alone. A NASA engineer calculated that if the material was iced, it could have hit the shuttle with a force equivalent to that of a 500lb safe hitting the wing at 365mph."

Columbia moved to launch-pad 39a on 9 Dec 02. Columbia launched 17 Jan 03. By my reckoning it spent 39 days in the coldest temperatures Florida has had on offer in the last 100 years. The fact that, over many temperature cycles, the ET foam "worked" (and then cracked to its substrate due to ingress of moisture) should surprise no-one. Once the tank was filled with liquid hydrogen any trapped water would become adhesive ice and hold the ET foam in place (although cracked) until two things happened - aerodynamic heating and the drop [below the level of the foam's cracks] of the hydrogen fuel (as it was being used up during the launch). At that point (approaching about 400 kts) any weakened area of foam substrate (still stiffened by its water content in the form of ice) would lose its icy adhesion, detach and head for the Orbiter. The aerodynamics of the combo unfortunately had it hitting at what would prove to be the Orbiter's weakest point (the easily shatterable leading edge RCC tiles just forward of the wheel well's outer forward corner).

[PickyPerkins]

I have been looking again at the re-entry image taken by the USAF in New Mexico and first posted by DrSyn on 8th Feb 2003.

I posted several processed images the next day, a (http://home.earthlink.net/~pickyperkins/_uimages/wingcuff1.gif) and b (http://home.earthlink.net/~pickyperkins/_uimages/wingcuff2.gif). The last figure shows the right wing superimposed over the left wing, and what I assumed (and still do) was ablated material ahead of and behind the left wing.

http://home.earthlink.net/~pickyperkins/_uimages/wingcuff3.gif
The images above are the original image on the left, followed by the same image limited to 3- and 2- levels of gray respectively (all seen from below), and a photo of STS-107 on the launch ramp (seen from above).

It looks to me as though much of the leading edge of the left wing cuff may be missing, and if ablated material is present perhaps more structure may be missing than appears to be the case in this figure.

Missing material was not evident in my first post because the right wing cuff was superimposed over the left wing cuff hiding the latter. If I had done the superposition both ways the missing areas would have been evident.

http://home.earthlink.net/~pickyperkins/_uimages/wingcuff4.gif
This figure shows the 2-level image and its mirror image, and the two superimposed. In superimposing these two images I have made the nose and wingtips coincide. The LH half of the superposition shows the ablated material ahead of and behind the left wing, while the RH half again suggests to me that much of the leading edge of the left wing-cuff may be missing.

So I am inclined to think now (as suggested by DrSyn for different reasons) that burn-through may have been INITIALLY far ahead of the wing and in particular much further forward than where the sweep back of the leading edge changes, and subsequently into the wheel well possibly from inside the wing cuff or fuselage.

If this is so perhaps the Boeing and NASA assessment that the damage to the underwing wing tiles was tolerable may have been correct, and that other damage further forward on the cuff was fatal. The tile hit map in the article titled, “From the beginning, foam was a concern for NASA” (http://www.orlandosentinel.com/news/custom/space/orl-columbia-graphics,0,7508362.photogallery?index=3) in the Orlando Sentinel linked to by DrSyn shows that most of the hits to STS-87 (more than 300) were on the wing cuff areas and not on the lower wing surface or leading edge. There might have been hits on STS-107 not visible to video cameras on the ground..

What do other people think? http://home.infi.net/~blueblue/_uimages/pi.gif

[OVERTALK]

Picky
Not really following your argument here. But caution, I may just be being dense.
"The LH half of the superimposition shows the ablated material ahead of and behind the left wing, while the RH half again suggests to me that much of the leading edge of the left wing-cuff may be missing. So I am inclined to think now (as suggested by DrSyn for different reasons) that burn-through may have been initially far ahead of the wing and in particular much further forward than where the sweep back of the leading edge changes, and subsequently into the wheel well possibly from inside the wing cuff or fuselage.

I gather from this that you disagree with the proposition that the jagged projection ahead of the left wing might be the hyper-heated plasma bow-wave (many orders of magnitude hotter than anything ever seen before) associated with a failed and shattered RCC section 6 or 7 (see below). A knowledgeable friend of mine says that "Yes, it would be opaque as far as a camera is concerned, just like the heat off the desert sands creates mirages and heat-haze - but only much more so" That's where I got the idea of the "flat-plate" effect. Consider that the reason why the Orbiter's wing leading edges are so relatively blunt is because the designer's choice was to absorb high mach re-entry heat in the bow-wave created ahead of a blunt wing section. Once you take away just one of those curved LE RCC sections, you are left with the inconel support brackets and an oblique flat plate of the aluminium wing. An erosion process quickly starts courtesy of the hyper-heated plasma and this is now being referred to as the "zipper effect" (which causes adjacent RCC tiles to be shed progressively out along the wing).
http://www.iasa.com.au/folders/Safety_Issues/RiskManagement/leadingedge-4_files/ww3d.jpg
The trail behind (in that photo) is the detritus of that process. So as well as the inside of the wing being"eaten from the inside out" (once the gap between the flat-plate LE and wheel-well was broached), the LE flat-plate effect would have grown in length, creating greater adverse yaw and roll effects. Evidence for this has been found in the fact that the Orbiter parts recovered have had a fine coating of black aluminium oxide and the leading edges of ceramic tiles have sprinkled into them the once molten orange beads of one of the alloy metals found in Inconel 718 and 600 (the melted RCC support brackets). Hope you're following this line of thought. I'd be interested in why it might be invalid.

Basically it comes down to what I've said before. Give one of those solid RCC sections a square-on icy hit and shatter it and then there's really nothing retaining the pieces in situ (in addition to the all-important RCC anti-oxidant coating being pierced). After a few hot/cold cycles facing towards or away from the sun in orbit and the mildest manoeuvre would throw a large chunk of that shattered RCC tile (which is exactly what apparently happened from the manoeuvre logs - as recorded by Radar). The scene was then set for the erosion, wheel-well broaching and L.E. unzippering process. The early pre-dawn pyrotechnics over California would have been those section 6 RCC carbon fragments hyper-heating to a white glow and detaching.

A wedge-shaped elastomeric sacrificial Leading edge protective launch shield (for half a wing-span each side) is what the NASA Doctor is likely to order. That should adequately protect the RCC and burn away promptly without drama on re-entry, but without compromising its "in atmosphere" abort glide performance. In addition I cannot see NASA ever again foregoing in-orbit inspections of critical areas. Two-part exothermic mix "once only" overlays could be applied to any areas thought dicy. With the right composition goo, they just shrink into position and would protect against the sort of development that, with Columbia, started right at the entry interface and continued for 10-15 minutes.

[PickyPerkins]

OVERTALK I am not disagreeing with anything you are saying. I assume all the “flat-plate”, zipping, and other processes you refer to went on, and that we do see ablated materials ahead of and behind the left wing.

To summarize, there seem to be 3 possible areas of INITIAL damage:

(1) Under the wing, studied by Boeing and concluded to be tolerable.
(2) Leading edge, now under study by the CAIB.
(3) Wing cuff almost as far forward as the cockpit.

I am just suggesting that there is a hint of evidence for (3).

But I don't see any evidence as to whether (2) preceded (3), or the other way around.

But I do suggest that (3) could have initiated (2), but that (2) was unlikely to have initiated (3).

Cheers, http://home.infi.net/~blueblue/_uimages/pi.gif

[DrSyn]

I wish I had time to stop and discuss the above in more detail, but I am seriously busy at present and not just with flying! I agree with you, OT and PP, on the substance of what you guys are saying. As far as I can tell, a primary line of thought on the Board revolves around a breach at RCC 1/2 starting the "chain".

Do remember that the Kirtland shot was taken barely a minute before the total and highly visible disintegration started. Prior to that, whilst still in darkness, several "flashes" had been well observed as she passed across the dark sky. If, as is now being suggested, these were the evidence of zippering from the glove (cuff) rearwards, by the time they snapped her from Kirtland, the leading edge would have been well strippped back.

Tech note: Inconel melts at around 1350ºC, so not too quickly in that plasma. Any exposed Al surfaces, however, would be melting like cheese. Hence the complexity of the probable heat paths and patterns.

Therefore, that pic, with any additional heat effects described in above posts, would be quite accurate. However, it is not showing the initial cause/source, but merely the final state of Columbia just before she was overwhelmed. Hope that makes sense.

Also, I would just repeat what I have said previously: bear in mind that there was probably more than one damage point (as per previous flights ad infinitum). This time, unfortunately, it involved the RCC sections. Any one of them would be fatal. Thus, what did which first is largely academic. The issue remains to stop bits coming off in the first place.

Check out the 1999 Annual Report (http://spaceflight.nasa.gov/shuttle/reference/1999_shuttle_ar.pdf) (sorry - 3.6mb PDF!), and see what they were saying about possible on-orbit damage to the RCC and the proposed fix (search "Inconel"). They were thinking in terms of micro-meteorite damage of up to 0.25" and its catastrophic effect in the wrong place. Not a hunk of debris "the size of a briefcase". You'll see what I'm getting at. The lower area of the RCC was considered most critical.

Of the three pieces of debris that detach from the ET in the crappy launch video, one which makes a fleeting appearance may have been well inboard, and one appears to strike the underside near RCC 7-9, IMHO.

Really must dash, but will chip in as time permits. God bless pioneers, all.

[OVERTALK]

Dr Syn and Picky

Yes we are agreed except about the initial damage being that far forward on the wing cuff. It would appear to me to be so very tangential to the airflow that any telling blow would have had to be a ricochet forward (unrealistic).

The yellow highlit section in the diagram above (and anywhere further outboard) would be my guess for the position of the initial damaging blow by the ET's icy foam. The damage wouldn't necessarily be visually apparent - but once shattered, the positional (retention) integrity of an RCC section would be compromised (as would its anti-oxidation preventive coating).

The in-fuselage sensor record of overheating should be able to be explained away by conductive heat along a metal structural member. Like Dr Syn, I'm very busy and may have missed the basic reason as to why the forward wing cuff now figures (apart from the very "open to interpretation" graphic transpositions and superimpositions).

[PickyPerkins]

This is a 2 line summary of what I was trying to say above:

The USAF photo reduced to 2 levels of gray shows a narrower left wing cuff compared with that on the right wing.

IF the left wing cuff is actually narrower, then some of the left wing cuff may be missing.

That's all.

I have no other reason to suggest damage to the cuff.

Note added on March 13th, 2003

Except, of course, that most (by a large margin) of the debris hits (http://www.orlandosentinel.com/news/custom/space/orl-columbia-graphics,0,7508362.photogallery?index=3) are on the underside of the wing cuffs.

http://home.earthlink.net/~pickyperkins/_uimages/pi.gif

[ORAC]

LA Times - 12 March:

Shuttle Investigators Look at Possibility of Weakened Wing.
Damage resembling pinholes is found on Columbia's left leading edge. Area may have been more vulnerable to a collision with debris.

HOUSTON -- Columbia accident investigators said Tuesday that they have found most of the leading edge of the shuttle's left wing and have discovered extensive damage that may help explain how the orbiter broke up on Feb. 1.

Investigators are looking at the possibility that the leading edge, which sustains some of the hottest temperatures on the shuttle skin as it flies back to Earth, was weakened through years of wear and tear that left pinholes and voids, investigators said.

The damage was similar to what termites cause in wood, said Harold W. Gehman Jr., chairman of the Columbia Accident Investigation Board. In this case, the voids occurred in reinforced carbon material just a quarter-inch thick that shields the aluminum wing from temperatures of nearly 3,000 degrees.

The voids and pinholes by themselves probably did not cause a failure in the leading edge, but they could have made the wing more vulnerable to a collision with debris, Gehman said. The board is still trying to assess whether the shuttle was damaged on liftoff by foam debris falling from the shuttle's external tank or by a collision with something in space.

"It is possible that the foam striking a healthy orbiter might not have done enough damage to cause the loss of the orbiter," Gehman said. "But it is possible that foam striking an unhealthy orbiter that had problems ... could do some damage. Is it an event she could have survived at age 10 but that she couldn't survive at 21?"

The Columbia was on its 28th flight when it broke apart, killing all seven astronauts aboard. It flew its first mission in 1981.

The concerns about the leading edge panels are not new. NASA has commissioned or conducted at least a dozen studies in the last decade looking at the panels. The studies examined damage by orbital debris, such as micrometeoroids, and pinholes that were first discovered on the Columbia in 1992.

The leading edge is constructed of a thin layer of material known as reinforced carbon carbon, sandwiched between two coatings of silicon material. The pinholes penetrate the exterior coating, allowing contaminants to eat away the interior carbon and leave voids, the investigators said...............

The investigators have some of the pieces from almost all of the 22 leading edge panels that line each wing. Notably, the panels from the left side show significantly more damage than the ones from the right side, Gehman said.

Investigators want to know how NASA and its contractors inspected and maintained those leading edges and whether the procedures were adequate, said Maj. Gen. John Barry, a board member. A team of investigators next week will visit the Lockheed Martin Corp. plant that provides the panels, he said. On six prior shuttle flights, orbiters returned with their leading edges damaged by debris, micrometeoroids or other causes, Barry said.

A Boeing official said Tuesday that "several of the wing leading edge RCC panels were reinforced to resist penetration or damage" when the Columbia went through a 17-month overhaul in Palmdale from 1999-2001. The official declined to provide details, saying the company needed approval from NASA to release the information.......

Other studies during the late 1990s raised the possibility that hot gases during reentry could enlarge pinholes that were appearing on the panels but concluded that the problem was unlikely to endanger the spacecraft or its crew. The microscopic holes were discovered in 1992 as NASA officials inspected the Columbia shuttle after its 12th flight. Inspections found the pinholes in other orbiters and NASA officials concluded that the holes generally developed after 10 to 15 flights, although the Columbia seemed to have the worst experience with them.....

[DrSyn]

There are links to the RCC "erosion" problems on the main sites (see previous posts), including detailed pictures. The article posted by ORAC contains some prime BS from Boeing in the line, "The [Boeing] official declined to provide details, saying the company needed approval from NASA to release the information...". I suspect that the line translates " . . and as an official spokesman for Boeing, I haven't a clue what I am talking about, so I'll pretend that it's a state secret to fob-off you journos . . ."

The 1999 Annual Report (http://spaceflight.nasa.gov/shuttle/reference/1999_shuttle_ar.pdf) (3.6mb PDF, as per my previous) stated it quite openly and clearly. I'll quote it directly as some of you may not have beeen able / had time to view it.

"Another safety improvement the SSP implemented was additional thermal wing leading edge protection to prevent wing structure over temperature/failure and potential loss of vehicle due to a hole in the wing leading edge. Current wing leading edge capabilities permit a 1in. hole on the upper surface of any panel. But on the lower surface, no penetrations are allowed on the lower surface of panels 5-13. In these locations, a hole generated by orbital debris would allow heat from the plasma flow during entry to quickly erode the 0.004-in. thick Inconel foil of the “Incoflex” insulators. This will cause a loss of insulating properties and exposing the leading edge attach fittings and wing front spar to direct “blast” from the hot plasma.

"The upgrade to include additional insulation would allow single entry with a penetration of up to 0.25 in. diameter in the lower surface of reinforced carbon-carbon panels 9 through 12 and up to one inch on panels 5 through 8 and panel 13. The design team evaluated requirements for meeting the 0.25 in. requirement.

"A variety of design requirements also considered during the evaluation including minimum weight with no additional post-flight inspections. The implemented design solution after analysis and testing were complete was to add high-temperature Nextel 440 fabric to the Incoflex insulators with one layer for panels 5 through 7 and 11 through 13 and two fabric layers for panels 8, 9 and10 (highest heating environments).

"Overall weight increase to the orbiter was 53 lb. This hardware is currently implemented on OV-103, OV-104 and OV-105 and OV-102 during the maintenance down period ['99-01]." (My emphases)

It may or may not be relevant, but note that panels 1-4 were not included. Also, 107 launch-debris impact is believed to be on the lower surface of the LE, and only orbital, not launch, debris is considered in the above scenario despite earlier experience. No intention of insulting anyone's intelligence here but, just to clarify, due to high alpha (40º) during max re-entry heating, the lower surfaces bear the brunt.

Off to bed :(

[ORAC]

CNN - 17 March - Shuttle lost a 'steady stream' of debris.

HOUSTON, Texas (AP) -- Columbia lost "a steady stream" of pieces from California all the way to its final breakup over Texas, as wires in its left wing burned and shorted out, shuttle officials told the accident investigation board Monday.

"We continue to be shocked that we had debris coming off the orbiter as we crossed the California coastline," said NASA flight director Paul Hill. He is leading debris recovery efforts in the West, which so far have yielded no wreckage.

Later, to illustrate his point, Hill showed a video that was a composite of 15 to 20 amateur videos sent in by citizens.

Hill expressed amazement that during much of the time debris was falling and sensors were going haywire -- probably from hot atmospheric gases that had entered a hole in the left wing -- "the vehicle flew perfectly, no indication of what was going on in flight control."

Aside from unusual temperature and pressure readings and sensor dropouts, "the vehicle flew like a champ right up until the breakup, so that did surprise us," he said, testifying in the second hearing of experts before the investigation board. Another hearing is set for Tuesday morning.

He and another shuttle official, Doug White of the NASA contractor United Space Alliance, said the sensors probably started blinking out one by one as the wires burned inside the left wing and, in some cases, simply shorted during Columbia's doomed re-entry on February 1.

The investigation board suspects the left wing was breached possibly by launch debris 16 days earlier. At least three pieces of insulating foam or other material on the external fuel tank snapped off and hit the wing.

In the videotape Hill showed, the shuttle is seen as a bright, white object against the dark sky; 15 times, a piece big enough to be seen came off. Twice, a flash accompanied the shedding object, perhaps the result of combustion -- in other words, the pieces may have been burning when they came off.

Hill told the seven board members present that without the videos, "We wouldn't know any of this. These people are definitely our heroes."

An expert in spacecraft re-entry, William Ailor of the Aerospace Corp., said 10 percent to 40 percent of the pieces that typically fall from a returning spacecraft usually survive atmospheric re-entry. Most of that falls in the ocean and is never recovered, however, he noted.

He advised the board to focus the debris search on the early wreckage and on parts of the shuttle of particular interest, like the left wing.

He said it is critical to the investigation to find some of shuttle pieces that fell out West. So far, that hasn't happened.

[UNCTUOUS]

The reason why those coast-crossing sources of brilliant light detaching from the Columbia won't be found is that they were almost certainly highly incandescent particles of carbon from the shattered portion of the left wing's RCC leading edge breaking away (see previous OVERTALK posts from a few weeks ago).

In the pre-dawn darkness they would have appeared very bright but soon burnt up almost completely. Anyone familiar with the carbon arc searchlight as used on Maritime Patrol P2's and P3's will explain to you why the carbon feed-rod burns up but punches out over 200 million candle-power in the process. The RCC is made from the same stuff.

So looking for carbon particles that are likely to have been latterly very small would be a vain quest. I would be very surprised if anything is ever found West of Ft Worth.

[OVERTALK]

It is also worth noting that the RCC on the Orbiter's leading edge is usually protected from oxidation by a layer of silicon carbide and the propensity of carbon for micro-cracking is deterred by an impregnation with tetraethyl orthosilicate. see link here (http://www.iasa.com.au/folders/Safety_Issues/RiskManagement/rcc-1.html)

Both of these protection's integrity would have been shattered by the impact of the icy foam stalactite that probably shattered a section of leading edge (part of which was thought to have been radar-detected in orbit floating nearby after a minor manoeuvre).

On re-entry, departure of the rest of that shattered RCC section (#6 or #7) would have inevitably started the unzippering of the RCC sections further outboard). Behind the RCC sections there is only the various Inconel alloy RCC support brackets and the aluminium flat plate of the real wing leading edge. Oblique Flat plates and hypersonic shocks being capable of many thousands of degrees hotter plasma than a normal re-entry, it's not surprising that the wheelwell was broached and eaten out by hot plasma, or that the lateral/roll control system was eventually overwhelmed.

Perhaps a sacrifical elastomeric wedge on that inboard leading edge would deflect shattering icy blows on launch and yet not affect in-atmosphere abort glide performance. I'm willing to bet that the fixes when they come will be simple and relatively straightforward.

[PickyPerkins]

Can anyone who attended or heard the CAIB proceedings on March 17-18, 2003 comment on what was said? I heard some of it on the Internet using a 56k modem, so unfortunately none of the charts were readable and I also missed any comments about the earliest events on the timeline.

Two items I did hear:

(a) asymmetric wing roughness and its associated asymmetric heating were considered unlikely to have occurred because the directions of the yaw and roll were not characteristic of asymmetric turbulence induced by wing roughness.
(b) FAA radar had tracked what is thought to be debris all the way down to 1,000 ft. in the California/Nevada border area.
(c) The shock wave generated by the nose normally impacts the wing at about RCC Tile 9, so higher temperatures may tend to occur there.
(d) The feature seen projecting forward of the left wing in the USAF photograph taken in New Mexico (which I have previously referred to "ablated material") could possibly be caused by intersecting shock waves.

I am particularly interested in anything said about the earliest events on the timeline.

Cheers, http://home.earthlink.net/~pickyperkins/_uimages/pi.gif

[OVERTALK]

Apparently someone is following OVERTALK theorising on Pprune -albeit 3 weeks later.

Was 'mystery object' a shuttle clue?
Investigators paying more attention to radar blip on 2nd day


HOUSTON, March 18 — Frustrated investigators of the Columbia tragedy are still trying to find a connection between apparently minor launch damage to the shuttle’s wing and the subsequent failure of that wing on return to Earth. They are now paying more attention to one potential gap-bridging clue, and some observers are dismayed that the clue was not recognized soon enough to do some good for the doomed shuttle and its crew.
THIS CLUE is the small “mystery object” that apparently detached itself from the shuttle after about 24 hours in space, on Jan. 17. It slowly drifted away, fell into a lower orbit, pulled ahead of the shuttle and burned up in the atmosphere over the South Pacific three days later.
“It was something that more than likely came loose,” Air Force Brig. Gen. Duane Deal speculated last month. Deal, a member of the Columbia Accident Investigation Board, is also commander of the 21st Space Wing at Peterson Air Force Base, Colo., which provides missile warning and space control for the U.S. military and allies.
Another board member is James Hallock, manager of the aviation safety division at the Department of Transportation’s Volpe Center. He recently speculated that a segment of the shuttle’s thermal protection system — perhaps the reinforced carbon-carbon bumpers along the front edge of the wing, or the tile-covered carrier panels that connect these bumpers with the regular tiled surface — was hit so hard that its attachments broke, but the segment was held in place through launch by air pressure.
“That’s one of the scenarios we’re thinking about,” Hallock told journalists Tuesday.
The mystery object “could conceivably be a carrier panel,” he noted. “It’s the right size.”
The radar blip from the foot-long fragment was so weak that Deal’s space trackers did not even notice it during the flight. Only after Columbia was lost on Feb. 1 did they manually review the 3,000 raw records from their worldwide tracking network. It took five days to find the radar signature.

LOST OPPORTUNITY
Although the object may still have a tale to tell investigators about the cause of the accident on Feb. 1, it is what the object failed to tell NASA in real time — before Columbia was lost — that some observers find particularly dismaying.
For two weeks after launch on Jan. 16, NASA managers had been struggling with the question of whether to request images of Columbia’s possibly damaged left wing from Pentagon telescopes in space and on the ground. In the end they decided there was not enough evidence of potential harm to justify the effort.
But all the while, the additional evidence that might have changed their minds — radar returns from what looked like a piece broken off the shuttle — was sitting unsought and unrecognized in a military database. Nobody at NASA apparently thought to ask the Pentagon to look, and nobody on the military side realized the raw data might have contained anything important.
Board members privately have told MSNBC.com that knowledge of the existence of such evidence would clearly have prompted NASA to demand imagery from other sensors. The remote imagery would have provided the best bet for inspection: Even if Columbia astronauts had made a spacewalk, that section of the wing would have been blocked from their view by the unfolded payload bay door.
Had the mortal wound to the shuttle’s wing been recognized, other options — involving extending Columbia’s flight while rushing to launch a rescue shuttle — might have become feasible.
Even though the “mystery object” failed to trigger alarms during the mission, it may still help clear the way for resuming shuttle launches by leading to an understanding of what went wrong during Columbia’s flight. Currently, there’s a gap in that understanding, due to an apparent “disconnect” between causes and effects.
WHAT HAPPENED WHEN?
Accident investigators trying to understand the Columbia catastrophe have thoroughly examined launch data apparently indicating that, despite the impact of several objects on the left wing, no visible damage occurred and nothing detectable came off. Yet a careful analysis of data from the very beginning of the shuttle’s descent through the atmosphere, 16 days later, shows that under aerodynamic stresses only a fraction of the strength of those at launch, strange turbulence appeared and small pieces began coming off almost immediately.
What could have happened between ascent and entry? The mystery object may tell the story.
There are several clues helpful in identifying the nature of the object. The rate at which it slipped from orbit can determine its mass-to-area ratio, which can be compared with candidate pieces from the shuttle. Its radar “signature” — the brightness it reflected at various radio frequencies — can also help choose among possible candidates.
Soon after the tracking records were released, retired NASA space debris expert Donald Kessler told NBC News that the object’s quick descent from orbit indicated it was “a small piece of debris.” Radar returns suggested that it was about a foot across and slowly tumbling.
Ted Molczan, a highly respected Canadian amateur satellite tracker, has just completed a detailed analysis of the object’s descent from orbit. The speed with which it decayed can tell a great deal about its density, and this in turn can help indicate which part of the shuttle it could represent.
Molczan measured the density of the leading candidate materials, including different types of tiles and thermal blankets that may have come off the shuttle. He found the object’s drag characteristics were most consistent with the physical properties of the heavier components of the shuttle’s heat shielding. Tiles and blankets would have been too light and would have fallen out of orbit within hours instead of days.
During the board’s news briefing a week ago, Maj. Gen. John Barry reported that the Air Force Research Lab at Wright-Patterson Air Force Base in Ohio was “proceeding rapidly” to obtain “radar signatures on a number of items from tiles, RCC [reinforced carbon-carbon], blanket ... and carrier plates.” NASA provided the samples from its supplies of shuttle spare parts.
Hallock reported the preliminary results Tuesday: “We’ve performed tests in a radar chamber. A tile doesn’t register, a blanket doesn’t even register.” This corroborated Molczan’s analysis that the object could have been one of the heavier components of the shuttle thermal protection system.
If the object observed in space were a dense fragment of the shuttle’s thermal protection system, it may have been from the wing’s leading edge or near it. So it could have been held in place during ascent by the wind load. But the question remains why it then came lose in orbit.
The answer may be that space is “an interesting heating environment,” in Hallock’s words. “It’s very cold, then there’s sunshine every 90 minutes. These temperature extremes do things to materials.”
Retired Adm. Harold Gehman, the investigation board’s chairman, added: “And just before the object was spotted, the shuttle had just done a yaw maneuver.” Such a maneuver might have caused a lose piece to drift away from Columbia.
Radar tests continue, and the Pentagon is now searching for any satellite observations of the meteoric flash the object would have made when it hit the atmosphere. It may have left enough traces to provide sufficient information to close the gap on the mystery of the Columbia disaster. The tragedy is that the object’s message of warning was never heard in real time.

James Oberg, space analyst for NBC News, spent 22 years at the Johnson Space Center as a Mission Control operator and an orbital designer.

[PifPaf]

I've heard that they finally found the "black box". Maybe we get some new information...

[PickyPerkins]

From the NY Times today:
------ Start quote -------
…… The device was not related to in-flight experiments …. but was itself an experiment. It records information on aerodynamic pressures, heat, vibration and acceleration onto magnetic tape ….. The recorder that was recovered was designed to begin working 10 minutes before the shuttle reached the atmosphere and had a two-hour data capacity …….
------ End quote -------
And a good chance of some answers.

And from the Orlando Sentiel:
------ Start quote -------
.... Columbia -- which was the oldest shuttle and the first to fly -- was the only orbiter in the fleet equipped with the device. "It was part of the original package to obtain entry data," NASA spokesman Kyle Herring said. "Columbia was much more instrumented than the other orbiters to gather this type of data." ...
------ End quote -------

Note added March 21, 2003
From the NY Times today:
---- Start quote ------
…. The tape is magnetic, similar to the kind used in a tape recorder. ….. The recorder …. gathers data from about 800 sensors in the fuselage, wings and tail that measure temperature, air pressure, vibration and strain on the shuttle's frame. The information does not include any systems data like the position of flight control surfaces, or hydraulic pressure or tire pressure. …….. Engineers sometimes reconfigured the recorder and sensors between shuttle flights to measure different information. It was useful for scientists trying to understand the upper atmosphere and the shuttle's performance in it, experts say.

The box ……. is one of a kind, said James Hartsfield, a NASA spokesman. The shuttles built after the Columbia carry recorders that gather information from 200 to 300 sensors, Mr. Hartsfield said. The recorder stores some information digitally, as a computer does, and some in analog form, as does an ordinary tape recorder. It is turned on and off by ground controllers and is normally started up 12 minutes before liftoff and runs until 6 minutes after the shuttle's main engines shut down after it reaches orbit. The recorder is switched on again 15 minutes before the burn that propels the shuttle out of orbit, which comes about 30 minutes before the shuttle re-enters the atmosphere. For the Columbia's re-entry on Feb. 1, it was turned on just after 8 a.m. Eastern time. The shuttle was lost a little less than an hour later. The recorder was installed under the floor in the Columbia's mid-deck area. It will be sometime next week before investigators know whether the tape has any data at all, he said.
---- End quote ------
†

[PickyPerkins]

The latest revised timeline indicates that when the Columbia was about 235 miles west of the California coast, the temperature of the “Supply Water Dump Nozzle” located near the forward part of the left wing cuff showed a rate of rise which went off scale and took 48 seconds to return to normal rates of rise of temperature. The location is shown in this diagram:

http://home.earthlink.net/~pickyperkins/_uimages/wingcuff5.gif

This sudden heating at least 21 feet forward of ANY of the RCC tiles occurred 15 secs. after the first abnormal rise of temperature in the wheel well, and 46 secs. after the start of a persistent drag to the left started.

Its significance seems to me to be that it shows something going on very early in the failure sequence much further forward than any of the RCC tiles.

While there were clearly events going on in the wheel-well by this time, it does not seem likely that wheel-well events could cause a temperature rise up near the leading edge of the wing cuff more than 20 feet forward of the leading RCC section.

It seems to me more likely that either there were at least two independent events going on, or that there was a common cause located at least as far forward as the Supply H2O dump Nozzle, e.g. in or near the forward part of the wing cuff.

The rate of temperature rise went off scale and took 48 sec to return to normal rates. The fact that the readings subsequently returned to normal rates of rise suggests that the instrument and its cabling were intact and functioning while the rate of rise was off scale as well as when it later returned to being on scale.

All this was going on while the Columbia was about 235 miles west of the California coast.

I realize that this is not a currently popular area of discussion, but I am curious as to why there is no discussion, either on Pprune or by the CAIB, on one of the earliest anomalies and the one physically located furthest forward on the Columbia. It seems to me to be worth talking about.

http://home.earthlink.net/~pickyperkins/_uimages/pi.gif

[OVERTALK]

Picky

Assume that, after some extremes of towards or away from sun exposure). a largish segment of a launch-shattered RCC section departed the leading edge in orbit during a mild manoeuvre i.e. this being what eems to have been logged on radar. Upon re-entry the remaining segments of that RCC section would have rapidly heated up, oxidized and were seen detaching brightly in the pre-dawn darkness as the Orbiter crossed California. This progressively laid bare the inconel alloy support brackets and the flat plate of the aluminium leading edge. Hypersonic shocks and flat plates aren't an area of intense study because like water and oil the two aren't really compatible. But what we do know from the photo taken about a minute before the breakup is that the super-heated plasma generated by an oblique flat-plate is many times magnitude hotter than anything before seen on re-entry (to quote a NASA investigator). That was seen on the photo as a projection ahead of the left inboard wing. Until such time as all/most of the RCC was gone from that section, or until the Mach No maximized, the resulting forward projecting plasma bubble probably fell short of the supply water dump nozzle. As the oblique aluminium leading edge became TOTALLY exposed to the hypersonic flow, the bubble would have gradually grown and projected further forward, affecting the SWDN temperatures. Clear so far?

However, how to explain the later reduction of that SWDN temperature? Easy. As the unzippering effect laid bare more and more oblique flat-plate leading edge outboard (i.e. as their RCC sections detached due to oxidization and their inconel brackets heat-eroding ), that forward projecting super-heated plasma bubble would have changed shape, fallen back and become more uniform span-wise. Think of it as holding your finger over a garden hose to achieve max range - and then later changing the spray pattern to a closer-in area coverage by changing the nozzle choke. Furthermore, the initial forward-projected plasma bubble resulting from a single lost RCC section would have been deflected inwards (towards the orbiter nose) by the intact RCC section outboard and alongside of it (i.e. next along outboard), until it too was eaten away by the superheated plasma.

Eventually, as the Mach Number dropped, the shocks would have also decreased in their forward projected size and temperature (although this would also have been a function of the loss of focussing by intact outboard RCC sections - as the damage ate RCC LE further and further outboard.

To me it seems a clear vindication, justification, verification, confirmation of the flat-plate theory of unintentionally generated destructive super-heated plasma - and tends to confirm what was first theorized based upon the USAF photo.

[PickyPerkins]

OVERTALK, you and I are like ships passing in the night. Try reading my post again (or for the first time?), particularly the first line ........ when the Columbia was about 235 miles west of the California coast ....

All the events I am talking about occurred over the Pacific Ocean.

The USAF picture was taken thousands of miles later.

Look at the sequence below and post again. http://home.earthlink.net/~pickyperkins/_uimages/pi.gif
http://home.earthlink.net/~pickyperkins/_uimages/wingcuff6.gif

[amanoffewwords]

The Italian Newspaper Corriere della Sera published a picture of the debris that has been collected so far. Kinda gives the scale of the problem in investigating the accident.

Link (http://www.corriere.it/gallerie/2003/03_Marzo/19/nasa.shtml)

(Haven't see it in any of the links so far - apologies if I'm duplicating)

[OVERTALK]

Picky

Sorry but I was pressed for time (above) and didn’t get to superimpose the suggested heating process upon the timeline. However that has been done now (at this link (http://www.iasa-intl.com/folders/shuttle/RCCdegTimeline.htm)) and in doing so, I found that a lot of other times, events and factors fitted neatly in as well. See what you think.

If you have any basic problems with the premise of the flat-plate effect, its generation of super-heated (and initially inward-focused) plasma and how that mechanism worked here in respect of the supply H2O dump nozzle and vacuum vent’s heating, then I’d probably need to start citing aerody references (and explaining it again). Let me know (with any specific exceptions/reqmt for clarification). I’ve cut out the insignificant events from the time-line in order to keep it simple.

The 1353:44 (Debris #1) first report of debris after coast crossing doesn’t mean of course that there wasn’t any prior overwater shedding of debris. The significance of the supply water dump nozzle’s heating (and the timing of it) is a watershed clue to there having quickly been a loss of residual fragments of that launch-shattered RCC section after the Entry Interface. Once that RCC section was substantially gone, apart from the inconel bracket there was just the oblique flat-plate leading-edge left. The fact that it both generated superheated plasma and that that forward-projected plume was focused inwards towards the nose by the (next along) intact RCC section is to me quite logical. However it may not be to others. The existence of the super-heated plasma plume also seems to [possibly] explain the non-nominal comms losses experienced on a number of occasions throughout their re-entry ride.

OVERTALK

[PickyPerkins]

The latest Timeline from the CAIB (Rev. 15) shows the first unusual event for the Columbia to be 19 sec earlier than in Rev.14, and is listed as follows:
------- Start quote ----------
13:50:00 Five events of unexpected Return link comm drop-out ……on upper left aft antenna (Tracking and Data Relay Satellite 171/W). S-Band comm drop-outs considered out-of-family based on comparison with previous 102 flight data at 39 degrees, into KSC, descending node and similar look angles to Tracking and Data Relay Satellite.
------- End quote ----------

QUESTION: Where is this “upper left aft S-Band antenna “ antenna located on the Shuttle?

There are three S-band antennas (2 Pulse modulated and 1 Frequency Modulated) on the lower forward fuselage, but where is the "upper left aft" antenna?

Since the Tracking and Data Relay Satellite was in the right place and the orbiter was in the correct attitude and the loss of communications was unexpected, it is possible that the antenna was screened by intermittent unexpected plasma. Hence the interest in where exactly this antenna was. Thanks.

http://home.earthlink.net/~pickyperkins/_uimages/pi.gif

[PickyPerkins]

CAIB says that after a preliminary review of the recorder, the board has learned that there are approximately 420 sensors with good data, with more to come. These sensors record mainly temperatures and pressures.

Earlist temperature rises were near RCC Panels 9 and 10 at 08:51:09. Data recovered from a recorder on board the shuttle show that abnormal heating began about a minute earlier than previously believed, slightly closer to the wingtip, according to the Columbia Accident Investigation Board.

Final contact with the shuttle was at 9:00:04 a.m., but data from the recorder continues until 9:04:18.

NASA estimates that the shuttle broke up 21 to 25 seconds after the hour.

http://www.orlandosentinel.com/news/custom/space/orl-asecshuttle31033103mar31,0,4673866.story?coll=orl%2Dnews%2Dh eadlines%2Dspace

http://home.earthlink.net/~pickyperkins/_uimages/pi.gif

[OVERTALK]

Some more detailed OEX data to be found here:

LINK (http://www.iasa.com.au/folders/Safety_Issues/RiskManagement/focusonRCC-3.html#oexdata)

They remain perplexed by the very high localized temperatures experienced early on and the larger-scale superheated flow patterns latterly (top of left wing, aft left fuselage and left OMS pod). Obviously those airflow patterns would have changed as the L.E. RCC sections and adjacent tiles got eaten away and also as the Orbiter entered its scheduled manoeuvre.

It really seems as though they are yet to discover or realize the accelerated super-heating caused by the localized flat-plate effect and hypersonic flow. That's probably because it's never been studied or experimented or modelled. It deserves to be -because it's what you get when such a leading-edge flaw develops.

[TACAN]

Maybe being paranoid, but it seems the spirit of openness promised after the Challenger investigation may be about to be compromised ?

SHUTTLE ACCIDENT BOARD ERODES OPEN MEETING LAW

The five non-governmental members of the Columbia Accident Investigation Board that is reviewing the February 1 space shuttle accident have all been hired as NASA employees, thereby enabling the Board to evade the open meeting requirements of the Federal Advisory Committee Act (FACA).

"If the civilians had not been hired by NASA, a federal law would have required the investigating board to meet publicly, justify any closed-door sessions and keep transcripts and minutes that would ultimately become public records," according to an astonishing story in the Orlando Sentinel, which first reported that the private board members were now NASA employees.

See "Board paid to ensure secrecy," by Kevin Spear, Jim Leusner and Gwyneth K. Shaw, Orlando Sentinel, May 11, here:


http://www.orlandosentinel.com/news/custom/space/orl-aseccaib11051103may11.story

TACCY :mad:

[lomapaseo]

Maybe being paranoid, but it seems the spirit of openness promised after the Challenger investigation may be about to be compromised ?


Give a thought to just how open you think an investigation involving hundreds of interviews of innoncent employees ought to be.

What protection of private information does an Ad-hoc board answering to the public have?

At least with the AAIB and the NTSB there are established rules governing the release of personal information. I doubt that there is a similar statue on the books regarding Columbia, hence the private sector umbrella protection.

We can't have our cake and eat it too.

[PickyPerkins]

Significant effects reported by the CAIB

http://www.caib.us/news/press_releases/pr030529.html

http://home.infi.net/~blueblue/_uimages/pi.gif

[arcniz]

Rather lame, how NASA churns out breathless press release upon press release about the highly visible cannon testing where they are just "discovering" that foam chunks at 500 mph will make ugly dings in the shuttle wing.

Bollywood, Texas-Florida-Washington style.

[brockenspectre]

For those not getting the US media, the following was sent to me by a friend in the States fyi.

A chunk of foam insulation fired at shuttle wing parts Monday blew open a gaping 16-inch hole, yielding what one member of the Columbia investigation team said was the ''smoking gun'' that proves what brought down the spaceship.

The crowd of about 100 watching the test gasped and cried, ''Wow!'' when the foam hit - the impact so violent that it popped a lens off one of the cameras recording the event.

The foam struck roughly the same spot where insulation that broke off Columbia's external fuel tank smashed into the shuttle's left wing during launch. Investigators had speculated that the damage led to the shuttle's destruction during re-entry over Texas in February, but Monday's test offered the strongest proof yet.

''We have found the smoking gun,'' Columbia Accident Investigation Board member Scott Hubbard said of the panel's seventh and final foam-impact test.

The 1.67-pound piece of fuel-tank foam insulation shot out of a 35-foot nitrogen-pressurized gun and slammed into a carbon-reinforced panel removed from shuttle Atlantis.

The countdown boomed through loudspeakers, and the crack of the foam coming out at more than 530 mph reverberated in the field where the test was conducted.

Sixteen high-speed cameras captured the impact, and hundreds of sensors registered movements, stresses and other conditions. The impact was so strong - packing a full ton of force - that it damaged some of the gauges.

''There's a lot of collateral damage,'' said Hubbard, a high-ranking NASA official.

Hubbard said the test results showed it would have been extremely difficult, if not impossible, for Columbia's astronauts to have repaired such a large hole in orbit. He stressed that the actual gap in Columbia's wing may have been a bit smaller - or possibly a bit bigger.

''We know that almost surely there was a breach on the order of 10 inches in diameter,'' he said. ''Here we've got one 16, so that's in the same ballpark in my book.''

He added: ''The board's goal was to connect the dots between the foam-shedding event and the proximate or the direct cause of the accident, and that's what this whole test program has been about. I think today we made that connection.''

Monday's test at the Southwest Research Institute - barely beating out an afternoon thunderstorm - best replicated the blow from debris that occurred 82 seconds into Columbia's liftoff in January.

Nonetheless, Hubbard expressed surprise at the results.

''It was in here,'' he said, smacking his fist into his belly. ''It was like, 'ah,' like that. It was a visceral reaction. It was shortly followed by 'Oh, my God.' ... I felt surprise at how it appeared, such a dramatic punch-through. But it is the kind of damage, type of damage, that must have occurred to bring down the orbiter.''

Two weeks ago, the investigation board identified the blow from the foam as the most probable cause of the accident that killed the seven astronauts. Hubbard said after Monday's test: ''I think foam hitting the wing leading edge of the orbiter at 500 mph is the direct cause.''

The board plans to release its final report by the end of this month. Much of the report ''is going to deal with the other types of causes, contributing causes and other elements of the orbiter program over the last 20 years,'' Hubbard said.

One month ago, another carbon shuttle wing panel - smaller and farther inboard - was cracked by the impact, along with an adjoining seal. This time, the entire 11 1/2-inch width of the foam chunk - rather than just a corner during previous testing - hit the wing, putting maximum stress on the suspect area.

The five other previous tests in recent weeks involved fiberglass wing pieces taken from the shuttle prototype Enterprise, housed at the Smithsonian Institution. Those, too, were damaged.

Hubbard said it is questionable whether the best set of cameras trained on the shuttle during liftoff would have detected such a large hole, if they had been in focus, and they were not. He declined to say whether spy satellites would have observed such damage, but he noted that it was a black hole in a black piece of reinforced carbon.

During Columbia's flight, shuttle managers rejected engineers' request for spy satellite images to ascertain the extent of damage to the left wing.

Among the board's preliminary recommendations to NASA: improve launch photography, use take spy satellites to check out orbiting spaceships, conduct better testing of wing panels, and devise an inspection and repair plan for astronauts in orbit.

Monday's test cost $3.4 million.


All I can say is that as everyone has known for some time that chunks of foam were in the habit of breaking off at launch and flying in the general direction of the Shuttle, why on earth didn't NASA conduct tests as to the likely outcome.

:(

[Belgique]

As you read back through the PickyPerkins, Unctuous, Overtalk and Brockenspectre posts of many months ago you could always see that this is where it was headed. I guess the next revelations from the CAIB will be that the foam may well have not just been foam but was likely carrying underlay, the denser hand-packed material and a significant water content in the form of ice.

The decision by the "powers that were" not to look further into the launch event and utilise all available resources to ascertain the integrity of the craft will now pass into aviation lore as an example of expedient wishful thinking.

There is a case for having a Safety Supremo in NASA whose brief is to honcho all aspects of safety. The "system" that existed was always best intentioned but sported zero efficacy when it came anywhere near the crunch.

If I was that 107 crew I'd be feeling a little bit killed by the system that was never equipped to intervene and sustain their system's safety.

[NineEighteen]

Forgive me if this has already been mentioned but were the crew aware/informed of the foam impact?

I realise that there appears to have been little that could be done by way of a repair but, as I recall, there were at least 5 pilots among the crew and I'd be very surprised if they didn't voice serious concerns about possible damage caused to the orbiter.

Belgique writes...The decision by the "powers that were" not to look further into the launch event and utilise all available resources to ascertain the integrity of the craft will now pass into aviation lore as an example of expedient wishful thinking. Were the commander and the pilot part of this decision?

----------------------------------------------------------------------------------

It seems I've answered my own question.

After posting the above, I visited the Johnson Space Center website (http://www.jsc.nasa.gov/news/columbia/index.html) and found this rather disturbing e-mail correspondence between STS-107 commander Rick Husband and a NASA official. (Note: I changed the messages around to read chronologically)

-----Original Message-----
From: STICH, J. S. (STEVE) (JSC-DA8) (NASA)
Sent: Thursday, January 23, 2003 11:13 PM
To: CDR; PLT
Cc: BECK, KELLY B. (JSC-DA8) (NASA); ENGELAUF, PHILIP L. (JSC-DA8) (NASA); CAIN, LEROY E. (JSC-DA8) (NASA); HANLEY, JEFFREY M. (JEFF) (JSC-DA8) (NASA); AUSTIN, BRYAN P. (JSC-DA8) (NASA)
Subject: INFO: Possible PAO Event Question


Rick and Willie,

You guys are doing a fantastic job staying on the timeline and accomplishing great science. Keep up the good work and let us know if there is anything that we can do better from an MCC/POCC standpoint.

There is one item that I would like to make you aware of for the upcoming PAO event on Blue FD 10 and for future PAO events later in the mission. This item is not even worth mentioning other than wanting to make sure that you are not surprised by it in a question from a reporter.

During ascent at approximately 80 seconds, photo analysis shows that some debris from the area of the -Y ET Bipod Attach Point came loose and subsequently impacted the orbiter left wing, in the area of transition from Chine to Main Wing, creating a shower of smaller particles. The impact appears to be totally on the lower surface and no particles are seen to traverse over the upper surface of the wing. Experts have reviewed the high speed photography and there is no concern for RCC or tile damage. We have seen this same phenomenon on several other flights and there is absolutely no concern for entry.

That is all for now. It's a pleasure working with you every day.

-----Original Message-----
From: CDR
Sent: Saturday, January 25, 2003 9:02 PM
To: STICH, J. S. (STEVE) (JSC-DA8) (NASA)
Cc: Shuttle Crew
Subject: RE: INFO: Possible PAO Event Question

Thanks a million Steve!

And thanks for the the great work on your part AND for the great poems! I saw the word Chine below and thought it was "China". I guess it's believeable that you might meet someone from China by the name of Main Wing :).

Rick

CDR
NOTE: This is private/personal mail and not for release to media.
:( Even so, I'm quite surprised the crew did not wish to check the damage themselves or request a satellite photo.

[brockenspectre]

sorry for a non-tech response here but I do recall watching NASA TV during this mission and being a little taken aback by the personal messages recorded/sent home ... each crew member said their piece and reiterated about how this was the best thing they had done (words to that effect). I firmly believe the crew were apprised that something beyond the average had occurred which potentially jeopardised their safe return to earth....but being the professionals they were, they chose to make their mark in the only way they could..by being there, being upbeat and positive to the last.

As I said in a more emotional response elsewhere they truly "reached out their hands and touched the face of god".

Let their sacrifice help man to reach the goal of safe manned spaceflight ... we were born to venture and it is into the stars that we go...

:) :ok:

[Belgique]

Yes
Then put yourself in Commander Rick Husband's place. He'd have had no cause for alarm. He had all the reassurance he needed.

Post-accident truth always has some shocking revelations. Reminds me of a large training jet formation where a couple of dual aircraft down the back reported a wing-touch. I got the deputy lead to drop back and inspect them and he came back as expected with "just a few paint-scrapes on the two tiptanks - no apparent leaks". Nevertheless I broke them off and told them to recover independently via a slow speed handling check at 10,000ft. That was SOP. I'd have been hung for doing anything else. Transpose to the 107 Shuttle situation and see the difference. It never hurts to err on the side of caution. It's called airmanship - although some might call it pessimism. You'll never be hung for it or wake up in a cold sweat of shirked responsibility. NASA apparently doesn't subscribe to that comic.

The Case for A NASA Safety Supremo

Remember, the sainted Jerry Lederer set up NASA's safety program. He is also the founder of the ineffectual (and wholly commercial) Flight Safety Foundation. Safety isn't something that can be run by committee or bought off the shelf.

[wes_wall]

Please excuse if this has been discussed previously, but I post the following on another pprune forum and it was suggested I browse your discussion. The test recently conducted stated a piece of foam was fired at the wing at 500 mph which yeild the results now believed to be the cause.

The questions I have are:

How could the piece of foam be traveling 500 mph since if departed the tank which was traveling the same speed as the wing ? How did the 500 mph speed become the bench mark? I am sure it has been published, but how fast was Columbia traveling when struck with the foam?

[arcniz]

Wes_W :

I cannot give you hard numbers, but a quick scan says the incident occurred more than 60 seconds into the flight at a vehicle velocity of a few thousand meters / second. The object that broke off was lightweight material, but thick enough to amount to 0.5 -1KG. Supposedly reliable sources at NASA calculated the 500mph impact velocity after an acceleration distance of ten or 20 meters. The information to do this calculation has been available for several years, along with the knowledge that these events happen with regularity.


As an institution, NASA has had the opportunity to do and be the best that mankind can accomplish in technology. Instead of that, it has become a retirement program for "old-timers", skimping on hardware and ignoring risks so it could keep the core crew of old-boy members on board until their pensions were funded.

Understandable, but a truly shi**y way to run an airline.

[avioniker]

I would like to take exception to the comment about NASA becomming a retirement home.

If you'll check you'll find that NASA is now populated and managed by people too young to remember the lessons of the past.

Bean counters cutting costs at the expense of safety and managers and supervisors making rules for things they haven't personally worked on are the problem.

Has everyone forgotten the first shuttle that lost tiles? Ground based cameras photographed the belly and reliable information was obtained to make a decision to allow the shuttle to land. That technology is still available today and is, in fact, considered out dated. There's better available for less money today.

What happened this time is that a few testosterone riddled mentalities were allowed to make the decision not to invite outside help to get more data. These insecure fools with little more knowledge or experience outside of school and NASA made a decision based on ignorance.

Ever wonder why very few people in NASA have any kind of certification like an A&P or JAA engineer's license? Their mentality is "patch it up, cut to fit, paint to match" and We don't need no stinking A&P.

I'm afraid that the old adage is very true in NASA and the entire industry's case: "Those who forget the past are doomed to repeat it".

If the commercial airlines were allowed to operate the way NASA does we'd see unimaginable carnage on a daily basis. I got my gray wiskers worrying about things I'd fixed in a hurry. At least I had grayer haired people around to ask for help.

Grow up NASA. When you hire an expert make sure he's done something in the field, not just written a thesis.:(

[DrSyn]

In answer to wes_wall, the debris detached when the Shuttle stack was some 82 secs into launch, at ±65,860ft and passing Mach 2.46 (±1620 mph) according to the best analysis. The relative speed of impact of the primary piece of foam on the leading edge was estimated at 775-820 fps (528-559 mph) from high-speed film frames. The time from foam release to impact was 0.2 secs. These figures are from the official investigation's Working Scenario released on 8 July but have been widely publicised for months. . . . . Also, (elsewhere) this is not a "tile" or "stalactite" issue. I hope this clarifies some of the confused posts above. The pic below shows the analysed debris path.

http://ourworld.compuserve.co.uk/DrSynHst/images/DebAna.jpg

For the benefit of those without broadband, I'll quote (in blue) a couple of relevant extracts from the report, as it is a 12mb pdf of 189 pages!

The damage was most likely equivalent in size to a 6 to 10 inch diameter hole or area broken from the RCC panel or an adjacent Tee seal. (and referring to the tests) The exact flight damage is unknown but is believed to be bracketed by these two tests* . . . . . The testing is important in that it confirms that the ET bipod foam can catastrophically damage the RCC.

This photo shows the result of the final test on actual RCC panels referred to by brockenspectre in her post above - the "Wow" factor. It is probable that the actual damage to Columbia was not this dramatic (re: * ).

http://ourworld.compuserve.co.uk/DrSynHst/images/RCC802.jpg

The report also includes ascent data on the leading edge post-impact: The temperature sensor on the leading edge spar behind RCC panel 9 showed a slightly higher temperature rise than seen on any previous Columbia flight. . . . . STS-107 had a 7.5 degree Fahrenheit rise that started very early during ascent (five to six minutes after launch). Although the data do not prove that the RCC was breached during ascent, the data are consistent with a possible flow path into the RCC cavity via damage in the RCC panels 6 through 8 area.

Re: various posts: personal messages of that nature are quite normal between crew and ground on all missions. The crew were routinely informed of the impact, were assured that it was not an issue ("in family" - a vile piece of NASA management speak on past damage) and were not expecting anything abnormal on re-entry. The video recovered shows this aspect with grim clarity.

Finally, avioniker, at this stage of the investigation, I remain convinced that Adm Gehman and his team have a firm handle on the situation you refer to. It seems unlikely that we will see a Challenger whitewash this time. As Sally Ride and others hinted a while back, 107, like 51L, was an avoidable accident where top-level complacency overrode professional engineering concerns. There will be major structural (sic) changes. Unfortunately it took the lives of another seven good people and an irreplaceable ship to achieve it.

[wes_wall]

Thank you DrSyn for the very detailed and clear explanation. I too concur with the findings. Anyone having experienced a bird strike or breif encounter with hail can relate.

[Bubbette]

Based on the newly issued report, this was just bound to happen. Disgusting. And worst of all, it seems they could have been rescued, had someone at NASA just thought for a minute.

http://www.caib.us/

http://story.news.yahoo.com/news?tmpl=story&cid=1896&ncid=1896&e=4&u=/nm/20030826/us_nm/space_shuttle_rescue_dc_4

[STS]

Have a look at this thread that's on Nasawatch - as one of the participants has pointed out in it, what is of great concern is how many of the NASA employees posting still wish to remain anonymous.

http://www.nasawatch.com/misc/08.27.03.caib.html

[arcniz]

Aviators take note. Look at your management.

Years ago, when he was feeling greatly the tragedy of Challenger, an old hand in leading-edge aviation commented to me that NASA would henceforth stand for: "Need Another Seven Astronauts".

So now again.

[arcniz]

Long story in Sept. 25 NY Times talks about efforts by concerned technical staff at NASA to obtain images of the vehicle while in orbit - all rejected by various levels of management . Describes a series of questionable top-down decisions ranging from "launch fever" to "chicken little" to the rationale
for not gathering information to detect a worst-case situation: "Well, if it's that bad, there's not a damn thing we can do about it."

Fine safety culture, huh?

direct to story url does not seem to compat with pprune front-end: (but it works)

http://www.nytimes.com/2003/09/26/national/nationalspecial/26ENGI.html?hp=&pagewanted=all&position=


NYT Gateway URL (http://www.nytimes.com/)

[arcniz]

A 6-part series just beginning Dec. 20 '03 in the aerospace-friendly Los Angeles Times will present an authoritative and scathing indictment of NASA's decisionmaking, management and technical culture in regard to shuttle operations and safety issues, based on content from the STS-107 post-crash investigations.

I cannot copy it for posting, but maybe someone else would like to. Failing that, just go see for yerself.


The series begins at:


http://www.latimes.com/news/nationworld/nation/la-sci-shuttle21dec21-1,1,6100851.story?coll=la-home-headlines


Some heavy breathing, but the point is clear enough to those who want to know it. An excerpt:



Call it forensic engineering or, more plainly, detective work.

The Columbia accident investigation was the most exhaustive scientific inquest ever undertaken.

Suspicion led down a hundred blind alleys. Investigators quarreled. Mission insiders tried to control the probe. Outsiders railed about secrecy.

The investigators mustered the most sophisticated techniques that science could devise — X-ray scanners, neutron beam machines, hypersonic wind tunnels.

They also used red food coloring, a bicycle pump, a hobby-shop hacksaw and a steam iron.

They conducted some tests in classified military laboratories, others in the nearest kitchen sink.

In arcane debates about trapped-gas analysis, radar cross sections and spatter metallurgy, they stalked answers to wrenching questions of guilt, shame and responsibility.


Leroy Cain's shuttle was lost, and now everyone in the room would be caught up in the investigation.

Every imperfection they found revealed a human face.

All that they discovered reinforced what Hallock learned by dropping his No. 2 pencil.

The space shuttles are by design unsafe.

As the most complex flying machines ever assembled, each shuttle contained more than 2.5 million parts, 230 miles of wiring, 1,060 valves and 1,440 circuit breakers. All of it had to function properly at extremes of speed, heat, cold, gravity and vacuum — the interaction of its parts just at the edge of human understanding and control.

From liftoff to landing, the shuttles flew in peril.

In orbit, they maneuvered through a hailstorm of 10,000 man-made objects larger than a softball and millions of smaller pieces of debris. At orbital velocities, an object no larger than a pea carried the force of a falling 400-pound safe.

During NASA's first 75 shuttle flights, technicians had to replace 60 cockpit windshields — at $40,000 each — because of pitting from debris.

But launch was even more dangerous. Orbiting junk at least could be tracked by radar and avoided.

For all their efforts, shuttle engineers could not stop ice and chunks of insulating foam from falling off the shuttle's 15-story external fuel tank and striking the spacecraft during its eight-minute ascent into orbit.

Agency engineers could not fix this fundamental flaw, nor could they craft a safer vehicle. They dared not abandon the only vehicle the country had to carry people into space.

So NASA continued to launch the shuttles, gaining confidence each time the crew returned safely.

"The program had been put in this box they could not get out of," said Scott Hubbard, director of NASA's Ames Research Center in Mountain View, Calif., and a member of the investigating board.

Blind to the consequences, they had constructed a trap and baited it with ambition.

[Bubbette]

This sounds like exactly what was said after the Challenger explosion.