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.

Saturn V

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

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.

Interesting overview, especially "abort options":

http://science.ksc.nasa.gov/shuttle/...n_profile.html

NoD

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.

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

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

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.

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

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

Re-entry imagery prior to STS-107
 

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

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

Bubbette,

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

S

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?

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

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

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?

Tyre fire?
 

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.

Tyre Fire??
 

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?

Few questions from a total non-specialist...

1. 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 ?
   
2. 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.
   
3. 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...