Right you are CONSO. I should have added that I was working on ISA more or less. My bad.

Relying on a poor memory here but I think each stage of a launch is insurable and the premium, for the satellite, will depend on the level of risk involved, because of the very nature of rocket launches the insurers will require a premium that assumes a total loss of the satellite. (Would be interesting to know if there will be any worthwhile salvage from this incident).


Don't know very much at all about rocketery but, if a test involving the live firing of the rocket is required, would it not be prudent to carry out this test before the valuable satellite is placed on top? :confused:

The problem is, the satellite is mounted on the rocket as part of the 'final assembly' process. I believe Space X does final assembly horizontally, then raised the complete rocket to the vertical. So the only way to do the final checks is to have the launch vehicle fully assembled - including the payload. Otherwise, to mount the payload it would be necessary to lower the rocket back to horizontal, which would effectively nullify the 'final' checks already performed.

In the bad old days of rocketry it was not uncommon to source at least two copies of parts for each satellite/interplanetary probe in case of such a mishap. I am taking a wild guess that now it is not so common, given the incredible expense and complexity of such a high capacity modern communication satellite.

Some good information on this lies in the "forum" of NASASpaceFlight.com discussing this very practice. Bottom line is that early mating of the payload and rocket is cheaper, given that the launch was scheduled for this weekend. Alas.....

Thank you tdracer and averow.

Speaking of Saturn V's,here's an interesting article about a recent project to get re-acquainted with the Rocketdyne F-1 engine.

http://arstechnica.com/science/2013/...-back-to-life/

MG23, re the boyancy forces: during acceleration, the bouyancy forces are actually *increased*. It was counter-intuitive for me too until I read (saw?) Elon Musk explain the thing: During upward acceleration of the rocket, the downward force (in the rocket's frame of reference) on the LOX is larger than the corresponding downward force on the He. Thus, the bouyancy is *increased*, not decreased.

I've seen videos of a car driving round a roundabout with a helium baloon inside. It looks *really* weird when the baloon is pressed toward the *inside* of the roundabout (i.e onto the driver)...

deSitter, you mention the report from RSO´s Self-Destruct as 2nd boom. Given the sudden RUD without any visible clues beforehand - could that maybe have happened in first place? RSO´s ordonance gone wild?

Thanks TWT, for the Saturn V article. I just had good read through it. The stats and figures are monsterous! I feel the same awe as I got when I found the same sort of info on the V2 weapon. I remember struggling to absorb the key facts such as 500 hp (if memory serves) being needed just to drive the fuel pump for the main engine. 500 hp is a good amount of power for a decent road car at the start of the 21st century and they were using this much just to drive a fuel pump in the 1940s. Magic.

If you haven't read it it is worth getting hold of "Apollo" by Murray and Cox, there's a good account in there of the lengths that were gone to to try and solve the combustion instability problem (which would have been a project stopper if not fixed) mentioned in the article.

SpaceX have been totally transparent with their launcher failures and are far and above any other organisation in this respect.

The previous helium tank failure was traced down to a 3 D 4" square area by interrogating strain gauge outputs and applying different filtration to the raw data to produce the result.

This showed that the support struts could have suffered oxygen intergranular corrosion.
This was proven when lab tests showed a number of the struts had a chemical imbalance that could lead to this type of weakening.
The support struts were then manufactured in house.

The turbo pump produced 55000hp, quite incredible. The fuel pump on the Space Shuttle main engines produced even more and spun at 37000rpm.

Back at the ranch History
 

:cool::8
The helium tank issue brought back some very old memories re the Saturn first stage- I’m talking 1963-64. Working at Boeing at a facility which had some large steam- accumulators to run steam ejectors to simulate 100K altitudes for early ramjets ( BOMARC ) gave us a facility which allowed us to simulate some parts of the S-1C first stage oxygen tankage system using the accumulators as a large air supply to evaluate the LOX tank pressurization system. The GOX ( gaseous oxygen ) in the fight bird used some bleed oxygen from the turbo pumps to maintain some pressure in the LOX tank to prevent pump cavitation . It was mounted on the top of the dome and fed by a approx 4 inch diameter tube running up the outside of the tank. The concern was the effects of impingement on the top dome of relatively high velocity oxygen. So we built an upside down 1/8 section of the dome ( like a ski ramp-) mounted the distributor upside down in the correct relative location. The flight design distributor was like a large 3-4 foot diameter trash can with half of the cylinder made of ‘ regimesh ‘ - sort of a multilayer screen to break up the flow and then run it with air and monitor with tufts and some instruments the impingement and internal pressures, etc. Each test run was about 30 seconds on condition. But we had various photo and instrumentation and flow measurement problems which with running certain specific flow rates required so we made several test runs. About the 5th or 6th run ( 30 seconds each ) the distributor exploded ! Luckily We had some high speed cameras focused on the distributor .As the Engineer in charge I ordered 3 copies of the film to be made ASAP. Examination of some of the parts indicated a fatigue failure ( high pressure, high flow and supersonic noise can do a lot of things ). The test was on a friday. I called the designers in New orleans and told them I had destroyed the distributor- after convincing them I was NOT joking- they hopped a plane to be in Seattle by Monday .
Monday afternoon when I got the file, I was “ invited “ into the Seattle Program Directors office ( George Stoner ) to show the film and explain as best I could what happened. The film showed the beginning of a seam in the regimesh starting to unzip.[ NOTE- In normal flight the SIC stage runs for about 2 minutes and 40 seconds- our total test time on that unit was close to 3 minutes !! ]

Getting together with the designers- I suggested three changes - adopted- 1) an intermediate dome in the distributor with many many 1/4-3/8 holes, 2) the above ( below in flight attitude ) cylinder not of regimesh but many many 3/8 holes and 3) a change to holes in the supply tube from slots.
We fabricated such a design and ran and ran and ran it for three to four times the normal expected flight time with no problems other that some minor ‘ working” of fastener holes evidenced by smudges around the fasteners. As far as I know- that was the design that flew.

SideNote - we used 4 inch diameter SS tubing - special run of about 30 feet. Leftover tubing from the initial build was sold to a local junkyard as no problems were anticipated. I chased the tubing down, bought it back to fabricate the new tube design ( about 3 -4 feet used for the tests ) . The remainder tubing was again sold. Junkyard sold several 3 foot sections as local clam guns - ( seattlelites know what they are ) :)

Thank you for the video link.


Indeed. With a bit of searching I found a copy of the video in which some kind soul has synchronised the sound, making it a much easier (and slightly more informative) watch:

https://www.youtube.com/watch?v=maRTEzlSBLk

The initial blast (frame 1) occurred near the oxygen tank. That ignited the top of the tank and seemed to have forced a rupture of the fuel tank at the bottom.
The payload and second stage remained in place for seconds before toppling. Once it toppled, it fell to the ground where it created a blast and mushroom cloud of its own.

I'm not so sure that there wasn't an explosion. There are a couple of fragments that were ejected with considerable velocity from the original (frame 1) blast point. That was a diamond shaped blast - as you might expect from a relatively small container rupturing under pressure. Or perhaps it was just shaped from obstacles around it.

not sure where you got that from?

both 1st and second stages were fully fueled with RP-1, only the stage 2 LOX tank was still being loaded, reports suggest it was at ~80% at the time of the fire/explosion)

The reports said it was being fuelled for a static engine fire test, why was the second stage being fuelled I wonder? Perhaps something to do with structural considerations or just a test of fuelling process and equipment, it certainly won't have been fired in the test. Any ideas?

Most probably wanted to duplicate temperature effects and pressure effects of 2nd stage in relation to first stage- consider that in flight as first stage shuts down- momentary negative g would have some effects on valves and pressurization and fuel sloshing of 2nd stage LOX and fuel tanks. Without a detailed diagram of plumbing, valve types and sequencing one can only speculate. Liquid fueled missiles have been lost due to failures of certain valves needed to mitigate or stop flow effects of momentary negative g..