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Space Science

NASA Test Shows Foam Could Be Culprit 525

Posted by michael
from the 0.5mv^2 dept.
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."
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NASA Test Shows Foam Could Be Culprit

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  • happens often (Score:5, Informative)

    by jnguy (683993) on Tuesday July 08, 2003 @01:32PM (#6393830) Homepage
    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
  • woah (Score:2, Informative)

    by EMH_Mark3 (305983) on Tuesday July 08, 2003 @01:34PM (#6393858)
    deja vu [slashdot.org]
  • Longer Article (Score:5, Informative)

    by Unknown Relic (544714) on Tuesday July 08, 2003 @01:36PM (#6393887) Homepage
    A slightly more detailed article [foxnews.com] 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.
  • Minor curiosity... (Score:5, Informative)

    by Jin Wicked (317953) on Tuesday July 08, 2003 @01:37PM (#6393893) Homepage Journal
    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?
  • by sparkie (60749) on Tuesday July 08, 2003 @01:37PM (#6393904) Homepage
    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.
  • Re:happens often (Score:4, Informative)

    by geekee (591277) on Tuesday July 08, 2003 @01:38PM (#6393909)
    It only started happening after they switched to a non-freon based foam to make the environmentalists happy. Despite that this was a known problem on quite a few missions, they were more interested in being politically correct than in insuring the safety of the missions.
  • by HerringFlavoredFowl (170182) on Tuesday July 08, 2003 @01:39PM (#6393918)
    A quick check on Spacetoday.com [spacetoday.net] points to several good articles ...

    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]
  • Re:Eh... (Score:4, Informative)

    by Enry (630) <enryNO@SPAMwayga.net> on Tuesday July 08, 2003 @01:39PM (#6393922) Journal
    It was the prevailing theory of the media. NASA didn't have evidence either way, but now that they've done the testing and looked at the results, it's now the best theory as to what happened.
  • by core plexus (599119) on Tuesday July 08, 2003 @01:39PM (#6393924) Homepage
    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
  • Re:So What Now? (Score:5, Informative)

    by Enry (630) <enryNO@SPAMwayga.net> on Tuesday July 08, 2003 @01:41PM (#6393954) Journal
    NPR had a report last thursday covering the possibilities of repair in space. There's a lot of options, from filling the wing cavity with heat-resistent foam to wrapping the wing in titanium which will burn off during reentry (like the heat shields of Mercury, Apollo, etc.).
  • Noteworthy points (Score:5, Informative)

    by Beryllium Sphere(tm) (193358) on Tuesday July 08, 2003 @01:47PM (#6394027) Homepage Journal
    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.
  • Re:woah (Score:3, Informative)

    by Jeremy Erwin (2054) on Tuesday July 08, 2003 @01:52PM (#6394082) Journal
    NASA planned a whole series of tests. This test, the last of seven, used a panel taken from Atlantis (leading edge panel No. 8), and therefore most precisely approximated the conditions of Columbia's accident.
  • by Nyrath the nearly wi (517243) on Tuesday July 08, 2003 @01:54PM (#6394100) Homepage

    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.

  • It's not a dupe. (Score:3, Informative)

    by AzrealAO (520019) on Tuesday July 08, 2003 @01:55PM (#6394112)
    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.
  • Re:PC-ness kills 7? (Score:2, Informative)

    by Natedog (11943) on Tuesday July 08, 2003 @01:56PM (#6394129)
    ooops...shuttle, not shuddle :)

    but more important, a link [newsday.com]

  • Re:Eh... (Score:3, Informative)

    by WolfWithoutAClause (162946) on Tuesday July 08, 2003 @01:56PM (#6394133) Homepage
    Not quite. The prevailing theory was that it made a crack in the wing, not a gaping hole. Now they've seen the hole- it makes a lot more sense- the hot gases would have been chewing into the wing, really early on in the reentry.
  • Re:happens often (Score:4, Informative)

    by Psion (2244) on Tuesday July 08, 2003 @01:57PM (#6394141)
    Not only did they make the switch, NASA chose to do so in spite of a special-use exemption granted by the EPA. After returning from a December, 1997 flight, Columbia had taken 308 hits from falling foam debris, with clear indication of the potential damage (some of the scratches in the delicate tiles on the underbelly were over 3 centimeters deep). Nevertheless, NASA continued to use the more dangerous, "environmentally safer" HCFC-141b instead of the reliable CFC-11 propellant.

    Thanks for bringing this up!
  • by mortonda (5175) on Tuesday July 08, 2003 @01:59PM (#6394162)
    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.
  • Video available (Score:2, Informative)

    by dmccarty (152630) on Tuesday July 08, 2003 @02:00PM (#6394175)
    The San Fran Chronicle has a short MPEG available here [sfgate.com].
  • Local reporting (Score:5, Informative)

    by JCMay (158033) <JeffMayNO@SPAMearthlink.net> on Tuesday July 08, 2003 @02:02PM (#6394203) Homepage
    Our local paper, Florida Today [floridatoday.com], has more reporting [floridatoday.com] and it was the above-the-fold news today.

    From my point of view, this is the most impressive part of the whole thing:

    The real panels cost $800,000 each. So combined with the $1 million custom-built wing frame, the cost of the tests is $4.2 million not counting the fake fiberglass parts or money paid to Southwest Research Institute for use of its unique nitrogen gas gun.


    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!
  • Re:happens often (Score:3, Informative)

    by kmac06 (608921) on Tuesday July 08, 2003 @02:03PM (#6394213)
    Look for yourself [google.com]. (Its the first one)

    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)

    by gwernol (167574) on Tuesday July 08, 2003 @02:05PM (#6394230)
    It only started happening after they switched to a non-freon based foam to make the environmentalists happy. Despite that this was a known problem on quite a few missions, they were more interested in being politically correct than in insuring the safety of the missions.

    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.
  • by Beryllium Sphere(tm) (193358) on Tuesday July 08, 2003 @02:05PM (#6394232) Homepage Journal
    >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.

  • The insulation probably would have reached terminal velocity long before reaching that speed.

    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

  • by ceejayoz (567949) <cj@ceejayoz.com> on Tuesday July 08, 2003 @02:13PM (#6394315) Homepage Journal
    I thought the popular strategy was to make sure the shuttle could dock with the ISS, and allow the astronauts to get back to earth in the soyuz module the station has.

    Pity there wasn't enough fuel to reach the ISS orbit, and that the Soyuz module holds a maximum of three people.
  • by leeward (313589) on Tuesday July 08, 2003 @02:15PM (#6394329)

    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>

  • by Tmack (593755) on Tuesday July 08, 2003 @02:16PM (#6394345) Homepage Journal
    Even if hey had enough fuel to match the ISS's orbit, docking would still not have been possible. The only time they take the docking module with them is when they expect to dock with something. The shuttle itself only has an airlock to the cargo bay. Thats where they put the docking module, which isnt light. See the pic and links on this [nasa.gov] page. Since this was a purely scientific mission, the docking ring was not onboard to save weight, which in turn saves fuel, which saves much $$.

    Tm

  • rescue mission (Score:4, Informative)

    by vasqzr (619165) <vasqzr AT netscape DOT net> on Tuesday July 08, 2003 @02:18PM (#6394357)
    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."
  • by f97tosc (578893) on Tuesday July 08, 2003 @02:23PM (#6394410)
    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
  • by a_timid_mouse (607237) on Tuesday July 08, 2003 @02:35PM (#6394576)
    >Rip that same hole 3 times in a row, and I'm on board.

    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.

  • Re:happens often (Score:5, Informative)

    by Psion (2244) on Tuesday July 08, 2003 @02:37PM (#6394591)
    Nice try. Actually, they began using HCFC-141b with STS-86. Here's some relevant info on Columbia's damage after STS-87 in 1997. [nasa.gov]

    Note the source.
  • Re:happens often (Score:5, Informative)

    by kmac06 (608921) on Tuesday July 08, 2003 @02:41PM (#6394632)
    I looked at your link. You're wrong. Do a quick search on "Freon" in that page. Better yet, I'll show you what you get:

    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:So What Now? (Score:4, Informative)

    by WegianWarrior (649800) on Tuesday July 08, 2003 @02:42PM (#6394645) Journal

    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.

  • by Rich0 (548339) on Tuesday July 08, 2003 @02:48PM (#6394700) Homepage
    I don't believe that Columbia was capable of reaching the ISS's orbit even if they wanted to. The Columbia has a lot of extra safety equipment since it was the first shuttle and nobody was certain it wouldn't just blow up on the pad. It is heavier than the newer shuttles.

    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:happens often (Score:4, Informative)

    by gwernol (167574) on Tuesday July 08, 2003 @02:56PM (#6394783)
    Nice try. Actually, they began using HCFC-141b with STS-86. Here's some relevant info on Columbia's damage after STS-87 in 1997.

    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?
  • by FatAlb3rt (533682) on Tuesday July 08, 2003 @03:04PM (#6394863) Homepage
    The heat loads are similar while in a roll (within a 100 deg F or so but on the order of about 3000 deg F temps). An on-orbit cold soak and non-rolling entry may have bought a few seconds, but with the same result.

  • by Anonymous Coward on Tuesday July 08, 2003 @03:06PM (#6394878)
    I was actually starting to doubt the 500mph impact speed due to all the naysayers on here.

    Then I started using my brain.

    Drag = 1/2 * C * rho * A * v^2

    C = drag coefficient, we'll guess 0.4 (look it up)
    rho = air density, could not find exact value, so I'll guess less than half sea level (0.5 kg/m^3)
    A = area, we'll guess 0.5 meters (again, a guess)
    v = velocity of shuttle when foam detatched, I don't know, so I'll use the stated test velocity, which is actually too slow, but what the heck = 236 m/s

    Plug into formula: drag force = about 2800 N

    using F= m*a, and remembering that the foam had a mass of less than a kilo (0.8), this means that the foam was subjected to an acceleration of almost 3500 m/s^2, or over 350 times gravity.

    Even if some of the estimates of density, drag coefficient, or area are off, that v^2 term crushes them.

    Conclusion: The foam slowed down really fast once it came off the tank.
  • Re:happens often (Score:2, Informative)

    by nolesrule (152898) on Tuesday July 08, 2003 @03:34PM (#6395191) Homepage
    Mission numbers are designated in the order that the missions are approved, not in the order of flight. In this case, though, you are correct. 87 flew about a seven months before 91.

    88 flew between 95 and 96, about 6 months after 91.
  • by Anonymous Coward on Tuesday July 08, 2003 @03:38PM (#6395241)
    OK, I've become a bit annoyed by all of the people who are spouting off about how 500mi/h is way off for the impact velocity. I'm going to dust off my highschool math and physics and attempt to figure this out.

    According to:

    http://spaceflightnow.com/shuttle/sts107/fdf/107 as centtimeline.html

    The shuttle velocity at T+59sec was 1643mi/h. Since the impact occured at T+83sec, we can assume that the shuttle was going faster than this. I'm going to be very conservative and assume 1800mi/h.

    Shuttle velocity: 1800 mi/h (2640 ft/s or 804 m/s)

    Now, we need to figure out air resistance. Since I have no idea about any of the foam's characteristics, I'm going to base this on a human body. According to:

    http://hypertextbook.com/facts/JianHuang.shtml

    Human terminal velocity: ~56 m/s (200 km/h)

    More importantly, air resistance is proportional to velocity squared.

    This means that a human going at 804m/s (speed of the shuttle) would have ~44 times the air resistance as someone going at terminal velocity.

    I did this as a simple proportion:

    (56 m/s)^2 * x = (804 m/s)^2
    x = (804 m/s)^2/(56 m/s)^2 = 206.128

    I believe this means that the air resistance would then be generating the equivalent acceleration of 206.128 times the force of gravity on said piece of foam. That works out to 2022.116 m/s^2 (9.81*206.128).

    So, how long would it take a piece of foam under those conditions to accelerate to 500mi/h?

    500 mi/h = 223.5 m/s

    2022.116 m/s^2 * x sec = 223.5 m/s
    x = (223.5 m/s) / (2022.116 m/s^2) = 0.111 sec

    How far would it take the foam to accelerate to that distance?

    distance = acceleration * time^2
    distance = 2022.116 m/s^2 * (0.111s)^2 = 24.70m

    Given that the length of the external fuel tank is only 47m, this sounds within tolerances of my thumbnail calculation.

    The major thing to remember is that they aren't trying to say that the space shuttle accelerated 500m/h between the time that the foam broke off and that it impacted. They are saying that the force of air resistance slowed it down that much by the time it impacted.

    Feel free to point out all of the obvious math errors. This is /. after all.
  • Re:happens often (Score:2, Informative)

    by rufey (683902) on Tuesday July 08, 2003 @03:41PM (#6395274)
    Flights do not always fly in order. See the KSC shuttle flight archive list [nasa.gov].

    In this case, though, STS-87 did fly before STS-91.

  • by A Bugg (115871) on Tuesday July 08, 2003 @04:35PM (#6395711)
    I have but a single comment to your post, and that is yes it takes weeks to prep a shuttle for launch except in the case of columbia atlantis was on the pad and ready to go for its march launch.
    A Bugg
  • by Matthew Austern (259952) on Tuesday July 08, 2003 @04:59PM (#6395851) Homepage

    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 [ralentz.com] on the Challenger.

  • by cheeto (128748) on Tuesday July 08, 2003 @05:05PM (#6395887) Homepage
    You aren't quite recalling your orbital mechanics correctly. A burn in the direction of your orbit will increase the altitude on the opposite side of the orbit. A burn in the opposite direction (retrograde) will reduce the altitude on the other side.

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