Slashdot Mirror
NASA Test Shows Foam Could Be Culprit
Ben Hutchings writes "The BBC has a report on an impact simulation that aimed to recreate the impact of insulating foam on Columbia's wing. The result was a large hole that probably could not be repaired in orbit even if it was known about."
I was watchinbg something on channel 7 about this, and they mentioned that this happens at almost every shuttle launch. Apparently it happened, but didn't create such a large hole on another shuttle a few months before columbia. I guess they better fix their stuff before they go off blasting into space again. It also showed how everything melted down because of that hole, scary how such a minor thing can cause such disaster
A slightly more detailed article is available from fox news. A couple interesting things noted here that aren't in the BBC article is that this was the seventh and final test, and that in addition to the camera lens popping off, several other guages which were measuring the experiment were damaged from the impact.
I've been following this pretty closely since I live relatively near the Johnson Space Centre here in Houston, and quite a few NASA people come in where I work. I've heard a lot of talk about training the astronauts all to spacewalk, and be able to repair minor damage to the shuttle, but what exactly would they do if the damage was too severe to be repaired? Would a second shuttle have to be launched as a rescue mission? Would they have to just abandon the damaged shuttle in space, since it would be unfit for re-entry? There's a lot of talk of repairs but I haven't heard any predictions for scenarios where repair was impossible.
Perhaps NASA should start looking at new designs with potentially fatal flaws. Have they not been using this design for something like 15-20 years now?
My Webcomic: Asylum on 5th Street
It'll be interesting to see what the reaction to this failure will be.
Challenger didn't really rock the way we did Shuttle missions because the problems that led to its explosion were not core to how the Shuttles are built -- someone / some process screwed up and there was a relatively reliable way to make sure it wouldn't happen again.
Columbia, on the other hand, was destroyed because the design of the Shuttle is so fragile that once you develop an external problem, you're dead -- since they're using tiles that are individualized, there are no spares they could carry that would help them fix this sort of problem.
Hopefully, this will be a step in the right direction -- either a radical redesign of the Shuttle, or its abandonment in favor of a more robust solution.
No, the Columbia could not have docked with the ISS. The space shuttle was launched into a much lower orbit and would not have been able to propel itself high enough to reach the ISS. That is one of the 'problems' that has been brought up. I believe they are going to put more restrictions on where in orbit the shuttle can go. However, don't take my word for it. It's been all over the news and on Nasa's website.
A quick check on Spacetoday.com points to several good articles ...
SpaceFlightNow article
Florida Today article and it has three video's of the test
Orlando Sentinel article
Washington Post article
Houston Chronicle article
TastesLikeHerringFlavoredChicken
It's amazing to think that prior shuttle launches have had foam break off and strike the wing without this happening (according to Discovery Channel). Makes me wonder what was different, perhaps just the size of the foam chunk. It's good to know they finally tested it out to measure the impact. Tragic that people died first. Here's a link to another article on VOANews.com
The impact speed and angle were not worst-case, but based on average estimates. Real-life damage could be even worse and we were lucky, lucky, lucky before Columbia.
NASA officials resisted making the reinforced carbon-carbon panel available for destructive testing, because they take 8 months and $800,000 to make.
The X-15 was considered experimental throughout its entire career, and it flew 199 times, which is far more experience than the shuttle program has had.
All your questions can be answered with the Columbia Loss FAQ. (scroll down to section "VI: Preventative Measures and Rescue Attempts")
Briefly:
They did not have enough oxygen to last for the weeks it would have taken to prep and launch another shuttle.
Even if they could have lasted, there were only two space-rated spacesuits aboard. And STS-107 had no airlock.
STS-107 had nowhere near enough deltaV to be able to alter their orbit enough to dock with the ISS. This is because the ISS is in a weird inclined orbit to allow Russian supply fights to be able to make it to the station.
This wierd orbit is also the reason that no Russian supply fight could have made it to STS-107
All this was argued to death on sci.space.shuttle months ago. The bottom line was that the shuttle was doomed the moment the heat shield was damaged.
The ISS was out - it was on a different orbit and the Shuttle didn't have enough fuel to make the transition.
On the other hand, I have also wondered why the hell they couldn't send up an empty shuttle and bring everyone back on it. Moreover, once the Columbia had been emptied, they could have tried to bring it back with out bleeding off speed using S turns. The Columbia broke apart as it was slaloming and had just loaded up the damaged wing. Had they known the wing was busted, they may have been able to slide slip the whole way in and kept the damaged wing trailing on the backside the whole way down.
All those ideas go out the door when the shuttle manager said "Even had we known, there was nothing we could have done." For that sentiment alone, he deserved to go - it was a far cry from Gene Kranz'es "failure is not an option" attitude when Apollo 13 blew an oxygen tank.
They didn't just pull that number out of thin air. They looked at the film, calculated the distance the foam traveled in one frame, and thus the speed it hit. True, there's some margin of error in that, but there's an awful lot of intelligent people behind that number.
From my point of view, this is the most impressive part of the whole thing:
That's an awful lot of testing that's been done for a mere $4.2 million! Last winter I was involved with some testing that cost $500,000 and the result was a little 50-page report. Way to go, NASA! Hooray for SRI!
>wrapping the wing in titanium which will burn off
The hidden gotcha which you'd need to account for is that if you have bumps or roughness on the wing surface, you may create a little hypersonic shockwave which will create a localized hotspot downwind, potentially hot enough to burn through even the heat-resistant tiles.
A repair would have to be smooth enough to avoid creating more problems than it solved. Lots of computation and testing would be needed.
I still think your question is intereresting, I just don't think the armchair comparisons to a baseball dropped from a car are at all valid.
AccountKiller
Columbia rescue would have been difficult but feasible: investigators
Posted: Sat, May 24 8:33 AM ET (1233 GMT)
Harold Gehman, chairman of the Columbia Accident Investigation Board (CAIB), confirmed Friday that it would have been possible to mount a rescue mission had the damage to Columbia's wing been known shortly after launch, although such a mission would have been very challenging. Florida Today first reported Wednesday that an internal NASA study, performed at the request of the CAIB, showed that it would have been possible to launch Atlantis -- which was being prepared for a March 1 launch -- on a rescue mission as early as February 9 or 10. Atlantis would have rendezvoused with Columbia, whose crew would have conserved supplies and power to stay alive. Atlantis's crew would have then carried out spacewalks to send supplies and extra spacesuits to Columbia, so that Columbia's crew could be transferred back to Atlantis for return to Earth. Gehman said that such a mission would have been extremely difficult and hazardous, particularly because of the danger of falling foam during launch damaging Atlantis as well. Gehman said it may have also been possible to repair the damage to Columbia by stuffing a bag of water in the hole in the wing, then covering it with teflon tape. Even though either option could have been too risky to carry out, their existence contradicts earlier claims by NASA officials that there was nothing they could have done to save the crew. Gehman said those rescue options make decision by NASA not to seek spy satellite images of the shuttle "even more ominous."
They figured that falling foam could not be so fast; it isn't in everyday situations.
But common sense only applies to common situtations. In exotic situtions you have to use math and computers. Your basic intuition simply does not work.
And the difference here is that the shuttle was going extremely fast. I don't know the exact speed, but much faster than 850 km/ hour.
The math of this is that air drag is proportional to the square of the speed. On top of this the foam is much lighter than the baseball. So if the shuttle was travelling in say 4000 km / hour (~Mach 4); what will be the speed of the foam by the time it hits the shuttle?
You have to do math and simulations for this one. NASA did, after the disaster, and you should not throw out the results (that the foam had slowed down to say 3150 km per hour) because of your everyday experience with speeds below 100 km/ hour.
Your post is illustrative of how easy these mistakes are to make. In rocket science, you have to think about and calculate everything; because your intution does not work.
Tor