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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."
Why do they always mention that the astronauts couldn't repair the damage? They could still potentially be rescued if they had known about the damage. NASA still failed in their basic responsibility to those in space by not pursuing the potential damage further and not monitoring the basic condition of the aircraft.
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
Wasn't this already the prevailing theory? What exactly is news here?
deja vu
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how much supplies do they have on the ship? as in: so they discover a problem that wont allow them to re-enter... do they have enough food and stuff to allow them to stay up there a few more days, until possibly another shuttle could be launched with repair materiels, or at least to ferry the astronauts safely back to earth?
what about the ISS? could they have docked there for a while?
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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?
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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.
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
The impact was so violent that it popped a lens off one of the cameras recording the experiment and prompted gasps from about 100-strong astonished crowd.
When I hear of "entertaining" demonstrations to prove a point, I'm reminded of magicians before an audience and furrow my brow.
Is the real "secret" here a less visually spectacular flaw, not in a bodypart but in the design process and it's assumptions?
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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
It most definately could not be repaired in orbit. I can't find the links now, but I remember reading several articles about how the shuttle was designed and built, and how many of the tiles fall off when they are working on the craft in the hangers! To say nothing of how difficult it is even when the adhesive works. One of the articles went on in some detail about the flaws in the design. I'll keep looking, it was most informative. cp
Does this also account for the the angle at which the foam in the wing? They don't mention it so I thought it was a question worth asking.
My understanding was that the foam glanced off the wing at high speeds and wasn't simply "shot" into it from a right angle. I may be completely wrong (and would love to be corrected) on my misunderstanding.
This obviously wasn't the same kind of foam we use to sleep on when we go camping.
In all the coverage I've seen of the damage investigation the scientists and reporters have made clear that the Shuttle had essentially no repair capability, so even if the problem had been found, there was nothing they could do about it.
They never seem to point out that there was one thing they could do, which was stop anyone trying to land in it. Fire the thing at the moon (I've seen Space Cowboys, so I know it can be done!) and let the shuttle crew camp out until they could be rescued.
It always sounds like they expected the crew to bound happily aboard, perhaps sharing a rueful smile at the knowledge that they were going to die, but hey, there's nothing we can do about it right?
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BLAM!
Audience: "oooooo"
NASA engineer: "Folks, this COULD be more proof that MAYBE this is what POSSIBLY caused the accident."
Audience: "Oh, you mean "POSSIBLY" as in, there's POSSIBLY life on mars?"
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Well, I hate to sound callous and all, but... if this indeed was impossible to repair then... well, it was probably for the better.
I mean, I can't imagine having seven people up there dying slowly on live TV. That would have been terrible.
What NASA needs to do now is to just replace the shuttle with something better for crying out loud (the Russians have been doing space on the cheap for any number of years. The STS does not really save us that much money) and get on with life.
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.
Can the impact speed be really that fast? Before the piece of foam fell away from the shuttle, it was moving at the same speed. To impact at 850 km (530 miles) hour, the piece of foam would have to slow down 850 km/h during the short distance between falling off and hitting the wing... during 2 seconds or so. Are the numbers really feasible?
I think that this final test is a smoking bun because it shows that pieces of foam can do much more than just cause minor holes in the wing. that might allow a fatal stream of air into the shuttle wing. If Columbia had had a hole in it's wing like this test created, it probably wouldn't have made it anywhere near as close to the landing point as it did.
I'm guessing that this was something of a worst-case scenario, and it pretty much blew the socks off the testers.
(having gotten in my weekly quota of pun, I'm now gonna go do some real work).
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Why are they firing the foam at 500 mph? I haven't seen a good explanation of where they get that figure from.
As far as I can see, I'd imagine that the foam falls from the fuel tank/booster onto the shuttle wing. The rate of fall should be only the relative acceleration that the shuttle experiences during the fall. (Since both foam and shuttle are presumably moving at the same speed when it detaches from the launcher)
So the total acceleration should be the acceleration of the shuttle (max 3G at liftoff according to a couple of web sources) plus normal gravity - call it 4 G. At most, the foam could fall the full 56 meters of the shuttle/booster/tank height (and most likely substantially less than that).
So, a quick (and probably hideously wrong) calculation based on v^2=2 * Accel * Distance shows that the end velocity of a body falling 56 meters at 4g should be about 33 meters/second, or 119 kph (74 mph)
Anyone know where I've screwed up on this?
Why don't you call NASA, then, and tell them this? Clearly, it doesn't take a rocket scientist to figure out that they're wrong. I personally blame the French.
- A.P.
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The Challenger (as well as Columbia, and the newer vehicle that was being built - Discovery) had a flaw in the design of its O-ring that NASA itself knew could cause problems in flight. The design itself worked (proven by earlier flights of the shuttles). However, the design was not resilient to, as you said, external problems that were not properly thought up before-hand, such as massive fluctuations in temperatures (which led to the failure of the seal on the booster rocket).
A university student did an excellent case study on the Challenger incident, including the O-ring design "flaw," and what NASA did to improve upon the design.
If it were in NASA's tome of simulated problems, there would have been a way to make sure a rescue would have been possible. Even if we had to park the shuttle in orbit (or on the international space station) until a rescue could have been performed. It tires me to listen to the people that say "well, they would have run out of oxygen if they were not able to return immediately."
Fact: humans will never be able to calculate for every single variable in a system. It's just impossible. I completely agree with you. We will continue to develop better designs that will hopefully prevent further destruction and loss of life.
Ayup
This was the 7th Test, firing a chunk of foam at an actual Carbon-Carbon panel from Shuttle Atlantis. The first story from over a month ago, was a test on one of the Fiber-glass panels from Enterprise.
but more important, a link
\forall code \in C, \frac{\Delta readability(code)}{\Delta t} < 0
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.
The San Fran Chronicle has a short MPEG available here.
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"Sen. George Allen, R-Va., said in a televised speech on Tuesday that the brother of Columbia astronaut David Brown disclosed receiving an e-mail from orbit that conveyed the crew's "concern" about the left wing, the Richmond (Va.) Times-Dispatch reported in Wednesday's paper. According to the report, the senator said Doug Brown, who lives in Virginia, told him his brother's e-mail said the crew had taken a photo of the left wing.
Story
Columbia was in the wrong sort of orbit to be able to rendevous with the ISS, nor was it capable of generating enough delta-v to enter a rendevous orbit.
This is one of the reasons the board recommended that all future shuttle flights (apart from the already scheduled Hubble Servicing Mission), fly to the ISS, or in Orbits that are capable of rendevousing with the ISS.
Why would NASA be shooting the piece of foam at the wing of the shuttle at "about 850 km (530 miles) hour" (sic.)?! The shuttle is going slowly when just taking off in the relatively dense atmosphere of the surface of the earth. As it picks up speed in the thinner upper atmosphere it is also in an environment with less friction.
The initial report that I remembered hearing, within days of the catastrophe, was that the shuttle was already doing around 1900/mph, when the foam detached and hit the wing. It (the shuttle) was probably still greatly accelerating at that point, and devoid of thrust, an oddly shaped, and "relatively" light piece of foam would probably gain some relevant kinetic energy by the time it contacted the wing. I haven't heard any more recent information on the speed of the shuttle at the time of the contact.
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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!
I read the news story...including the part where they said, "we could do this again, and get a different result".
So, first, how about doing this at *least* three times?
THEN, take the average, and put the damn thing in front of a horizontally-mounted rocket engine, to simulate actual re-entry, and see if it happens...or if, as has happened in the past, the shockwave keeps the heat from penetrating.
Gee, if that happened, then they'd have to go back to looking for another cause...like (google for it) the diehard's analysis that it was stress corrosion cracking in the hydraulic lines that control the elevons. Loosing control of them would rip the wing *right* off.
But then, stress corrosion cracking shold have been caught...*if* they hadn't cut safety inspectors by 75%, and if the managers, in their own meetings, cared more for safety than for "being a team player, and meeting the schedule".
NASA's management strucure needs flattening, anyway - there's maybe 1 chief for 2 indians. Is that sane, to y'all?
mark
Because prior to this accident, the concensus opinion at NASA was that the foamed insulation was low-mass and crumbled easily enough that it didn't pose a threat to the vehicle. In fact, the mixture of foam being used had been in place for five years. In STS-87, the first time it was applied to Orbiter Columbia, foam debris caused 308 hits on the orbiter, some resulting in deep gashes. After changes in the method of application, the foam was rendered more secure, but chunks continued to break off in future flights.
Still, none of those flights exhibited the kind of damage that would lead to the Columbia tragedy until now. It seems perfectly obvious to "monday-morning quarterbacks" that the foam was a problem, but five years of experience suggested otherwise.
Until you can give me formulas and mathematical models, I think I'm going to have believe what the Rocket Scientists are telling me about their field. But, I defiantly see how you came to this conclusion, wheather is right or wromg.
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>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
People flying in a spacecraft, the thermal system of which is the only thing that stands between them and forces strong enough to neatly distribute their bodies across 200 miles of forest, should not have to "hope it never happens again".
The current Thermal Protection System is a dangerous, fragile and unreliable hack that should be thrown away and replaced with a more sensible system using modern materials and technologies that are proven and ready to use now.
--riney
Psst... Shuttle was moving, too. That's the point - the foam fell off and started decelerating due to drag... at the same time, the shuttle was still accelerating due to thrust. The foam still had a vertical velocity, but it was far slower than the shuttle's vertical velocity... basically the wing caught up with the foam chunk.
They "calculated" the speed of the foam chunk by measuring how long (in frames of the high-speed film) it took for the foam to travel a known length (top of shuttle to wing). Not super accurate, but probably within 10%.
-T
It really pisses me off, everytime I read something like that.
You'd be amazed what can be repaired if the only alternative is dying.
Tm
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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."
back in 1993, british amateur inventor maurice ward created a plastic he called "starlite", which would withstand temperatures of up to 2700 celsius (that of a nuclear explosion). does anybody know what temperatures are reached during reentry, or for that matter, what happened to ward & starlite? i tried googling but didn't find anything interesting.
ed
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
These people are capable of launching a spacecraft from a planet whipping around the sun, through continuously changing gravitational fields, for hundreds of millions of miles, and put it down on a spot the width of your city park. They know physics. To put it bluntly, these people are badasses. The last thing they deserve right now is the intellectual equivalent of a 2 year old arguing over politics with Kofi Annan...
Five years of experience, or One Fucked Up Powerpoint Slide?
Just like poor presentation of temperature data killed Challenger, poor presentation of the foam data killed Columbia.
Stupid goddamn PHBs and their fucking PowerPoint slides.
The foam strike happened shortly after the point called "Max Q", where aerodynamic loads are highest. Before then, the shuttle's still moving relatively slowly. After then, the shuttle's in thinner air.
Aerodynamic pressure at Max Q is usually quoted as 580 pounds per square foot.
The piece of foam that hit Columbia is usually described as "suitcase sized" and estimated to have been 1-1/2 or 1-1/4 pounds.
One square foot is a really small suitcase, but the foam wouldn't always have been broadside-on to the relative wind. So 1 ft**2 is the right order of magnitude. The ballpark figure for acceleration is then a = F / m ~= 400 g's.
Rounding off, since this is just back-of-the-envelope, 13,000 ft per second per second. 60 milliseconds would suffice to reach the speed used in the test.
s == 1/2 * a * t ** 2. Accelerate at 400 g's for 60 milliseconds and you've gone 23 feet.
The speed they used in the test is the right order of magnitude.
As someone else pointed out, NASA also had film showing the strike and could do frame-by-frame measurements to estimate the actual speed of the chunk.
You gonna pony up the ~$3 million for those three tests? Each one costs more than $1 million when you're using the Reinforced Carbon Carbon wing that exactly replicates the doomed shuttle's wing.
They test fired at several stronger, cheaper, fiberglass mock-ups to get their simulation right before they blasted away at the real thing (read very expensive). I for one am glad they took their time recreating the event as accurately and with as little waste as they did.
They could have used (basically an ICBM) a satellite launch rocket, put a supply shipment up there, and let them sit up there for a few weeks.
According to the legendary aeronautical designer, Burt Rutan, the shuttle is a very expensive and very dangerous vehicle. http://www.wired.com/wired/archive/11.07/space.htm l
In order to develop scramjets, NASA needs to ressurect the X-15 program. Hypersonic flight . With newer materials and newer rockets, they could go higher and faster than ever before. The X-15 reached 62.5 miles and the pilots even got their Astronaut wings. If that 62.5 mi altitude sounds familiar, it should. That's what you need to win the X-prize. It did close to 200 missions in 9 years and nowhere near the cost of the shuttle program. The X-15 would make a perfect platform to test designs. As a matter of fact it flew one mission with a mock scramjet aboard.
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It seems perfectly obvious to "monday-morning quarterbacks" that the foam was a problem, but five years of experience suggested otherwise.
This is exactly the type of bad logic that helped cause the first shuttle tragedy. The dangerous fallacy that "since it's worked N times before" that it "will work N more times".
*Anyone* who is in a man-critical environment can NOT use the simple fact that something hasn't been a problem yet to conclude that it isn't dangerous.
So prior example shouldn't be considered? While I concur that management erred in considering the threat from foam debris (and it's composition) to be negligible, five years of evidence that the system worked reliably argued that STS-107 was fine. Right or wrong, the evidence was on their side. Based on the media focus, it seems obvious that this is something that should have been investigated more clearly, but how many times had something similar happened on prior missions with no significant damage to the vehicle?
Yep, they were lucky those times, but there was no factual evidence to the contrary, and unfortunately, it took this tragedy to provide a single, compelling data point to the contrary. Had falling foam cause more significant, but non-catestrophic damage prior to STS-107, the warnings probably would have been given more attention, but until now, the only cost was expensive tile repair.
If I sit down in a chair fifteen times without it collapsing under me, it is hardly a "dangerous fallacy" to think it will continue to support me fifteen more times. It is reasonable to assume it will eventually break and fail, but no reasonable person will stop and examine their chairs every time prior to sitting in them. The shuttle is a remarkably complex machine, with extraordinary attention paid already to vehicle safety. There's going to be a lot of hand-wringing over this incident and a lot of finger-pointing until things settle, but in the final analysis, no system is perfect. It is humanly impossible to catch all accidents before they occur. Sometimes, unfortunately, it takes a catastrophic failure to highlight a problem before it is corrected.
And guess what? This won't be the last failure in space exploration/exploitation.
http://story.news.yahoo.com/news?tmpl=story&cid=53 3&ncid=533&e=3&u=/ap/20030708/ap_on_sc/shuttle_ear lier_breach
Gasses have breached the wing on a previous Atlantis flight. And they didn't even know about it until a postflight inspection, AND, it sounds like the damage almost went unnoticed, and the Atlantis would have launched with the damage from a previous flight, and no replacement of the faulty seal.
This damage was caused by the combination of a faulty seal, and falling ice.
The Columbia is being blamed on just the falling foam. But wouldn't you say that the heat shield was a faulty design?
Did the Soviet shuttle use tiles?
The X-33?
I recall during Columbia's first flight - the tile design was questioned in the press. The aluminum structure underneath, of course, is flexible, and it's covering, the tiles, is not. A few tiles popped off on that first flight, and subsequent flights - and it was mentioned that the wrong tiles falling off would have dire consequences.
Sad, that nobody sees this as an unacceptably risky design.
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> It's a fairly simple matter of plugging the in the right
>values for m, g, S, C, p, A, v0, and x0, and we'll settle this
>right now. If anyone knows what those numbers are I
>invite you to share them.
This makes a nice toy model but it won't cut it for estimating the relative velocity of the foam (which can be done more easily just by watching the video and using fifth-grade math: velocity = distance traveled/travel time).
First of all, the foam was very likely tumbling. So A isn't constant. Second of all, the foam was probably rougher in some places than others; so C isn't constant either. To solve both for the velocity of the foam and its orientation requires a nonlinear system of 7 differential equations. You'd also need to know the exact shape and surface characteristics -- clearly impossible to know at this point.
All is Number -Pythagoras.
The system of 7 equations you mention would more than likely be highly chaotic, meaning the results would be meaningless unless the initial conditions were known to extremely high accuracy. Of course this depends on the Lyapunov exponent of the specific system. I think we're wandering off into irrelevant territory here.
I think what is ticking me off is hearing people say "High school physics disproves this," wildly assuming that high school physics is not oversimplified and actually describes all possible scenarios. I wish these people would wake up and realize that "high school physics" is to physics as integer arithmetic is to mathematics...
For those who don't recognize the quote, the exact wording is: "For a successful technology, reality must take precedence over public relations, for nature cannot be fooled." It comes from Richard Feynman's appendex to the Rogers Commission report on the Challenger.
"The result was a large hole that probably could not be repaired in orbit even if it was known about."
Geez, I always thought you could fix anything with enough duct-tape.
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I seem to recall that on the first shuttle flight, when missing tiles were a *huge* concern, that the astronauts had some sort of chemical foam, or gel that they could use. It would burn off like the Apollo heat shields.
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