NASA Test Shows Foam Could Be Culprit 525
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."
So don't repair it! (Score:2, Insightful)
happens often (Score:5, Informative)
Re:happens often (Score:4, Informative)
Re:happens often (Score:2)
Also from what I heard NASA was still allowed to use freon-based foam if it still wanted to, but it switched anyway.
Re:happens often (Score:2)
Re:happens often (Score:3, Informative)
Or, if you're lazy [foxnews.com]:
"Despite that the Freon-based foam worked well and that an exemption from the CFC phase-out could have been obtained, NASA succumbed to political correctness. The agency substituted an allegedly more eco-friendly foam for the Freon-based foam.
PC-foam was an immediate problem.
The first mission with PC-foam resulted in 11 times more damaged thermal tiles on Columbia than the previous mission with the Freon-based foam."
Re:happens often (Score:4, Informative)
Thanks for bringing this up!
Re:happens often (Score:4, Informative)
NASA are in the process of switching foam types as mandated by the EPA. However STS-107 did not have the new "superlightweight" tanks with the new foam - the foam that was shed was the old foam. See the shuttle loss FAQ [io.com] for details.
So it did not "only start happening after the switch". Its clearly a problem with the foam system in general, and is not directly related to the type of foam used, as you imply. This conspiracy theory that "environmentalists" or a "politically correct" NASA caused the shuttle disaster is wrong.
Re:happens often (Score:5, Informative)
Note the source.
Re:happens often (Score:4, Informative)
True, but the foam shedding problems have been going on long before STS-86. See this [centredaily.com] article, for example:
"The first NASA-reported loss of bipod closeout foam was on the June 1983 launch of Challenger. That was followed by a similar foam loss on the January 1990 flight of Columbia. No records are available from those flights about the size of the foam chunk or damage to the shuttles.
A little more than two years later, the Columbia again suffered bipod foam loss, that time from both closeouts, during a June 1992 launch. A 6-inch divot was missing from the right closeout, and the left closeout popped loose, taking with it a chunk of intertank foam. That piece measured 20 inches by 10 inches by several inches deep, according to a debris and ice assessment prepared after the mission." (quote is about half way down the page)
So it can't simply be the switch to the new foam that caused the shedding problems, now can it?
Re:happens often (Score:5, Interesting)
So, yes, it most certainly is the new formula that caused the problems.
Re:happens often (Score:3, Interesting)
The first motorized car (Daimler and Benz) that used a combustion engine was in 1886. Look at cars in 1926. That is a lot more innovation than what was done in the first 40 years of computing.
There was a huge boom for car manufacturers prior to the Great Depression that was very similar to the dot-com boom. There was a tremendous amount of innovation, especially in clutch and brake design.
Cars di
Re:happens often (Score:5, Insightful)
"Since 1998, however, a revised tank model - a 'Superlightweight' tank - has been in use."
The same FAQ says in the next paragraph,
"In addition to the development of the 'Superlightweight' tanks, Lockheed also began using a reformulated lighter version of the inch-thick, spray-on insulation used on all external tanks in the mid-1990s. The switch was made to comply with an EPA mandate to limit ozone-depleting chemicals."
So the new foam came into use on *ALL* tanks (doesn't say 'only superlightweight'), starting in the mid-1990s, whereas the "superlightweight" tank only came into service in 1998.
The FAQ also says that the use of the new "Superlightweight" tank started with STS-91. But the same FAQ talks about the extensive tile damage found on the return to earth of STS-87, and it mentions that the new, 'environmentally-friendly' foaming method was used on STS-87. It also refers to this new foaming method being one of a few possible reasons for the extensive tile damage. STS-87 comes before STS-91 (unless they have some weird numbering system I don't know about), so it couldn't have used one of the new 'Superlightweight' tanks with its 'environmentally-friendly' foam. So it is apparent from this evidence also, that the new foaming method was used with the Columbia tanks.
If you are going to try to refute somebody, and then post a link to your supposed evidence, please read your evidence carefully so I don't have to waste my time responding.
Re:happens often (Score:5, Informative)
Four possible causes were put forth as to what caused the foam to separate from the External Tank:
1. The primer that bonds the tank foam to the External Tank itself was defective and did not set properly.
2. The aerodynamics of the roll to "heads up." The STS-87 mission was the first time this maneuver had ever been completed.
3. The change in the production methods of the foam to exclude the use of Freon and/or any ozone-damaging fluorocarbons.
4. An unforeseen shrinking of the External Tank due to cryogenic loading, leading to separation of the foam from the Tank and compromising its integrity and resistance to atmospheric drag at high velocities.
(emphasis mine)
So. The conspiracy theory that politically correct environmentalists caused the disaster is (possibly) right.
Re:happens often (Score:5, Insightful)
That makes all the sense in the world. Instead of blaming the engineers who made the decision to launch in the face of overwhelming evidence that:
a) Foam is falling off of the tanks (does not matter WHY)
b) Foam strikes are already shown to cause tile damage.
c) Ice strikes on Atlantis mission in 2000 caused enough tile damage to create a hot-gas breach on re-entry which was non-fatal. (but easily could have been).
These three points show that something was known about the problem and something should have been done. It doesn't matter WHY the foam fell off. It was known to be falling off. The problem was this decision-making process. Not the foam!
Re:computer modeling (Score:4, Interesting)
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.
Bad Documentation Kills. (Score:3, Interesting)
Five years of experience, or One Fucked Up Powerpoint Slide [edwardtufte.com]?
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.
Re:computer modeling (Score:4, Insightful)
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.
Re:computer modeling (Score:3, Interesting)
Eh... (Score:3, Insightful)
Re:Eh... (Score:4, Informative)
Re:Eh... (Score:3, Informative)
woah (Score:2, Informative)
Re:woah (Score:3, Informative)
It's not a dupe. (Score:3, Informative)
i have often wondered (Score:2, Interesting)
what about the ISS? could they have docked there for a while?
Re:i have often wondered (Score:5, Informative)
Re:i have often wondered (Score:4, Informative)
The ISS is in a highly inclined orbit (in order to launch resupply ships from russia the ISS can't just orbit the equator like most normal satellites). As a result only the newer and lighter shuttles are even capable of reaching its orbit.
In order to visit the ISS the shuttle would have to be launched with this in mind from the outset of the mission. A shuttle launched for this purpose could not deploy normal satellites or visit the Hubble. It isn't just a matter of the orbit being the wrong height - it is the wrong inclination as well.
Inclination is the angle the orbit makes with the equator. A zero inclination orbit stays over the equator all the time. A 90 degree inclination is a polar orbit (cruises over both poles and as the earth turns beneath it the orbit crosses every point on the surface of the earth). I think the ISS is around 30 degrees inclination.
To change orbital inclination you need to thrust at a 90 degree angle to the orbital velocity. It takes a LOT of fuel to make anything more than a minor change.
Inclined orbits need more fuel at launch time as well. A zero inclination orbit launched from near the equator has the advantage that on the pad the shuttle is already moving in the right direction with considerable speed (due to the rotation of the earth). All orbits of a given height require the same velocity to maintain. However, relative to the launch pad, an inclined orbit needs more velocity. The worst orbit from this standpoint is a 180 degree inclination - or retrograde orbit. This is one in which the ship is travelling east to west, and not west to east. The ship must take off and spend a lot of fuel just to get down to zero velocity (it starts off with velocity in the wrong direction due to the rotation of the earth), then it has to spend that much energy again just to get to where a 0-inclinction launch starts off. Then it must spend the normal launch energy to get into orbit.
During re-entry all this extra velocity has to be bled off as well. This doesn't cost fuel since friction is doing the work, but it does stress the tiles more.
Re:i have often wondered (Score:4, Informative)
All your questions can be answered with the Columbia Loss FAQ [io.com]. (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.
Re:i have often wondered (Score:3, Informative)
A Bugg
Re:i have often wondered (Score:5, Interesting)
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.
Three words (Score:2, Funny)
Re:Three words (Score:2)
See previous /. article [slashdot.org] for more information
Re:Three words (Score:2)
"If the women don't find ya handsom, they should at least find you handy"
Longer Article (Score:5, Informative)
Local reporting (Score:5, Informative)
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!
Minor curiosity... (Score:5, Informative)
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?
Re:Minor curiosity... (Score:4, Funny)
without potentially fatal flaws...
Re:Minor curiosity... (Score:3)
I believe that it would have been possible for the crew to ration everything to the bare minimum, long enough push up the launch of Atlantis to fly a rescue mission. Such a mission would have been fraught with danger, (short cuts on pre-flight safety, and it too might have been struck with foam on launch) but there would have been no shortage of volunteers to fly the mission, despite the risks.
I suspect they would have abandoned the shuttle, it wouldn't be cost effective to fly a repair mission. I don't
Re:Minor curiosity... (Score:2)
Given enough fuel on-board, why not just rendezvous with the ISS and hole up there until either another shuttle or a recue craft was launched? My space station design goes as far as the second death star, so I'm not sure if the ISS can even hold nine or ten people, let alone sustain them.
Re:Minor curiosity... (Score:3, Funny)
Re:Minor curiosity... (Score:3, Interesting)
Granted I got this info from the media so it could be a pointless thing to say, but it sure sounds good.. especially since I don't think they can just lob another shuttle into space on a whim.
It would also still leave a broken shuttle up in space, which I imagine makes for an interesting engineering problem once the business of keeping peopl
Re:Minor curiosity... (Score:3, Informative)
Pity there wasn't enough fuel to reach the ISS orbit, and that the Soyuz module holds a maximum of three people.
Re:Minor curiosity... (Score:4, Interesting)
in this case, where heatup during reentry would be a huge problem with a damaged wing, I was wondering if they could bring the shuttle in at a very oblique trajectory consisting of many orbits of slightly-decreasing radii to aerobrake it orders-of-magnitude more gradually than they currently do now.
Interesting idea (Score:2)
Reentry profiles (Score:2)
whatever happened to starlite? (Score:3, Interesting)
ed
Re:Minor curiosity... (Score:3, Informative)
Re:Minor curiosity... (Score:2)
Yeah yeah... (Score:2)
I seem to recall (Score:3, Interesting)
So What Now? (Score:5, Interesting)
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.
Re:So What Now? (Score:5, Informative)
Trickier than it sounds (Score:5, Informative)
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.
Challenger's O-ring led to new O-ring design... (Score:3, Interesting)
A university student did an
Re:So What Now? (Score:4, Informative)
And we're too cheap to give our astronauts some real protection, like thier own escapable lifepod, built into the shuttle's design.
Funny as it might seem, the problem of 'bail out' in space was studied closely in the fifties and early sixties. As usuall, the Encyclopedia Astronautica [astronautix.com] has more info, of which I have taken some samples from below.
Back in the early days of spaceflight it was envisioned that flying in space would be like flying any other kind of high-performance aircraft. Thought was therefor given to ejecting from a damaged craft, just as you can fom most military jets. They studied a one crew balistic capsule [astronautix.com] with a weight per crew of 327 kilograms and a six crew balistic capsule [astronautix.com], mass per crew 548 kilograms. Breaking away from the ideas of capsules, you had MOOSE [astronautix.com]; a inflatable heatshield and parachute combination with a weight of 215 kilogram. Paracone [astronautix.com] was a simular idea, but with an all up weight of 227 kilograms. An derivative of the existing systems for the B-58 lead to EGRESS [astronautix.com], with a weight per crew of 370 kilograms.
Despite this promising start, what did NASA come up with for the shuttle when it was designed? Yes, the infamous Rescue Ball [astronautix.com]!
As you can see, there really is technical reason why NASA shouldn't be able to equip the shuttle with 'lifepods', but another, very real reason. The lightest of the systems I've picked weights just under a quarter of a ton for each astronaut in question. FOr the seven man crew on Colombia, thats just over two tons to haul into space and back again - two tons less cargo. See why the shuttle don't have liferafts? They simply eats too much of the payload. It makes more sence to add more reservefuel to each mission, in order to make sure any shuttle could, if needed, rendevous with the ISS and stay there until a rescueshuttle / several Souyz caspules could be launched to pick them up.
Come on get some better links to the story ... (Score:5, Informative)
SpaceFlightNow article [spaceflightnow.com]
Florida Today article [floridatoday.com] and it has three video's of the test
Orlando Sentinel article [orlandosentinel.com]
Washington Post article [washingtonpost.com]
Houston Chronicle article [chron.com]
Noteworthy points (Score:5, Informative)
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.
A pinch of salt ... (Score:4, Interesting)
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?
Re:A pinch of salt ... (Score:2)
Big things being destroyed is cool to watch, even when it is something as simple as testing batches of concrete, when it leaves a pile of rubble that takes a dozer to remove.
You shoot anything with a 1lb object at 500+ mph and it is going to be entertaining.
another story (Score:5, Interesting)
Re:another story (Score:3, Insightful)
How do you get into NASA without passing highschool physics? If I asked these people -- the ones who declared that such an impact was not cause for concern -- what was heavier; a pound of feathers or a pound of lead, what would be their answer?
First a metric conversion issue that dooms a Mars mission now this.
"probably could not be repaired in orbit" (Score:3, Informative)
Accouting for angle and all? (Score:3, Interesting)
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.
Something missing (Score:3, Funny)
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?
Cheers, Paul
art of understatement (Score:3, Funny)
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?"
Just as well (Score:3, Insightful)
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.
Re:Just as well (Score:2)
The report I saw last night on the news interviewed a NASA engineer that begged for spy satellites to take pictures of the shuttle to look for damage. He was ignored.
Re:Just as well (Score:2)
Then again, a shuttle design thats not 20+ years old would probably help as well.
850 km/h in 2 seconds? (Score:4, Interesting)
Re:850 km/h in 2 seconds? (Score:2, Interesting)
Re:850 km/h in 2 seconds? (Score:3, Informative)
Re:850 km/h in 2 seconds? (Score:3, Informative)
As was pointed out elsewhere, you simply look at the film and attempt to measure how far the object moved in the last two frames before impact. Then divide by the time between frames. Gives a pretty good ballpark figure.>/P>
Re:850 km/h in 2 seconds? (Score:3, Insightful)
Emails that demonstrate how the shuttle was doomed (Score:2)
Regardless, pictures were asked for and management squashed it for failing to follow procedure. And now a shuttle is dead. TPP reports, anyone?
This is no surprise... (Score:2, Insightful)
And I'll bet a bee weighs a LOT less than the chunk of foam that hit the Columbia.
Hey, it's not like this was rocket science...just basic PHYSICS, for Pete's sake!
Excuse the raw humor (Score:3, Interesting)
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).
So here's my question... (Score:2, Redundant)
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 ac
How about a *real* test? (Score:3, Interesting)
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
a large hole that probably could not be repaired (Score:3, Insightful)
You'd be amazed what can be repaired if the only alternative is dying.
What makes me sad... (Score:4, Insightful)
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...
AP reports, it's not the first time! (Score:3, Interesting)
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.
Not even with Duct-tape? (Score:4, Funny)
Geez, I always thought you could fix anything with enough duct-tape.
Who Knew!?
-Goran
Re:At least they found the "smoking gun"... (Score:2)
"He also said he believed that repairing the damage to the wing while the Columbia was on orbit would have been a nearly impossible task."
I hate trolls
Hubble was designed from the start (Score:2)
It's got nice easy equipment racks, such that they can just pull one piece of science equipment out, and roll another one in and hook it up.
Quite a bit different from repairs, patching broken tiles on the Shuttle (each one is different, and actually quite brittle), or replacing the carbon-carbon leading edge panels.
Columbia could not have reached the ISS (Score:4, Interesting)
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.
Excuse me, but .... (Score:3, Insightful)
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
Re:This proves NOTHING (Score:3, Funny)
- A.P.
Re:This proves NOTHING (Score:4, Informative)
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
Re:Sound familar? I'll say the same thing I did th (Score:2)
I don't know if the ice factor was considered in the size/weight of the test piece here, but the tumbling effect can't be easily reproduced. Maybe the actual speed was lower, and they increased it for the test to simulate the effect of the tumbling of the piece.
Re:Sound familar? I'll say the same thing I did th (Score:4, Informative)
Re:Sound familar? I'll say the same thing I did th (Score:4, Insightful)
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.
I wondered the same thing... (Score:5, Insightful)
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.
This is the exact mistake NASA did (Score:5, Informative)
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
Some back of the envelope calculations (Score:4, Insightful)
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.
Re:Sound familar? I'll say the same thing I did th (Score:2)
Re:PC-ness kills 7? (Score:2, Informative)
but more important, a link [newsday.com]
rescue mission (Score:4, Informative)
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."
Re:Here's the equation. (Score:3, Interesting)
>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. S
Use stochastic physics (Score:3, Insightful)
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 dis