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Shuttle To Fly Without Safety Revisions 174

Posted by Zonk from the gotta-get-up-there dept.
HaloZero writes "In the face of safety concerns, NASA has decided to proceed with launching the Space Shuttle Discovery in July without changes to the external fuel tank. The article states that even though Discovery's last launch shed a huge 1-pound chunk of potentially devastating foam, they're willing to wait to change the spec on the disposable tank. The changes would modify the Ice/Frost Ramp assemblies, which prevent a buildup of ice on fuel lines and cables (as a side effect, they also have a tendency to dislodge large chunks of insulation)."
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Shuttle To Fly Without Safety Revisions More

Shuttle To Fly Without Safety Revisions

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  • Proposal (Score:5, Funny)

    by LiquidCoooled ( 634315 ) on Saturday April 29, 2006 @02:53PM (#15228905) Homepage Journal
    I think Nasa should coat the entire shuttle and tanks with materials cold enough to not freeze during take off and with a hard enough shell to survive the heat of re-entry.

    Yes folks, I believe we should coat the tanks and shuttle body with politicians and lawyers.

    Before you deride my concept as mere rambling, consider that they are now running the show anyway so we might as well make them useful.

    I did a quick survey amongst the remaining engineers and technical folks at Nasa and they all consider my proposal double plus good.
    • Wouldn't their incessant blabber drive the astronauts Nuts? A filibuster in space? Will the galactic federation council charge us with polluting space, if some of them politicians and lawyers break off during flight and drift into space? Gosh, the prime directive! We can't possibly risk them landing on a planet with intelligent life!
    • I was going to reference how similar that would be to the Reavers in firefly, but then I remembered the reavers used humans.

  • Adopting the credo of Mexican bus companies (Score:5, Funny)

    by iminplaya ( 723125 ) on Saturday April 29, 2006 @03:05PM (#15228951) Journal
    "Mejor muerto que tarde"

  • Flying without some of the safety changes (Score:5, Informative)

    by flooey ( 695860 ) on Saturday April 29, 2006 @03:12PM (#15228974)
    The summary is possibly a little misleading. Several safety changes have been made to the foam so far, but there are further changes they'd like to make. It's not like they're flying without any changes whatsoever. That's not to say that I completely agree with the decision, but it's an important point.

    • Re:Flying without some of the safety changes (Score:5, Informative)

      by iamlucky13 ( 795185 ) on Saturday April 29, 2006 @03:32PM (#15229042)
      Correct. Foam pieces falling from the area in question (the ice ramp) have been observed to be too small to cause major concern, based on their calculations and testing, or will safely clear the orbiter (I forget which). They had been considering replacing the foam in this area with heaters. There has to be some sort of protection or else ice might build up. Ice hitting something at 500 mph is a lot worse than foam. I assume the combination of not wanting to add another active system (which can fail) and needing extra power supplied while sitting on the pad were contributors to this decision.

      After the loss of Columbia, NASA removed a foam ramp from the tripod area that holds the external tank in place. This is where the piece that caused the damage came from. In Discovery's last flight (and I believe in some older launch videos), foam was also observed to come off the proturbence air load (PAL) ramp, which is another aerodynamic feature. This was also eliminated. Additionally, NASA is going to be flying a gentler flight profile on remaining missions (listed as "Low Q"). They lose a little bit of load capacity doing this, but the acceleration is lower and their speed is slower in the denser levels of the atmosphere.

      • Re:Flying without some of the safety changes (Score:5, Informative)

        by Frequency Domain ( 601421 ) on Saturday April 29, 2006 @04:14PM (#15229188)
        ice hitting something at 500 mph is a lot worse than foam.
        You'd think that ice would be more dangerous than foam, but you'd be wrong. I had the pleasure of chatting last December with one of the astronauts who was doing the accident review. According to her the danger is more from relative velocity differences than from mass, since kinetic energy goes up quadratically with velocity and only linearly with mass. The problem with the foam is that it has such a low density that it decelerates very rapidly from aerodynamic drag after breaking loose. Ice, because of its much greater density, retains it's velocity and hits surfaces below at a much lower relative velocity. Given a choice between being hit by a chunk of ice at a few tens of mph, and a chunk of foam with the a tenth of the mass at hundreds of mph, you're better off with the ice.
        • That is pretty much correct. However, the higher density of ice also raises some problems. It is much harder and it the force is transferred to the shuttle over a smaller area. NASA is reasonably comfortable ignoring smaller pieces of foam because they are pulverized without causing damage if they contact the orbiter. The smaller area of contact means less skin area resisting the impact and the hardness of the ice raises the chances, for a given KE, of damaging the skin or the brittle thermal tiles. Now I d

          • Re:Flying without some of the safety changes (Score:5, Interesting)

            by Frequency Domain ( 601421 ) on Saturday April 29, 2006 @07:29PM (#15229826)
            She specifically talked about foam vs. ice. She said that going into it, they all assumed that ice would be the greater threat because of hardness and mass, but after running lots of simulations (it was a simulation conference where I met her) they discovered that foam's propensity to rapidly decelerate made it a much greater threat in terms of KE once the shuttle picked up speed but was still in the atmosphere.
        • Nonsense.

          Assume chunks of equal area peal off the shuttle, so that the drag forces are equal (actually, as the foam slows down faster, drag force on it decreases a bit faster).

          drag.force = mass * drag.acceleration. So if the mass of the ice is 1/10th as much as the foam, a.foam = 10a.ice.

          The kinetic energy gained by falling some distance is mass*distance*acceleration. So with 10x the mass and 1/10th the acceleration and the same distance fallen, ice and foam should end up with almost the same kinetic ene
    • They're also going to be flying with changes that will allow them to detect if there was damage during launch that will cause another Columbia disaster. And if there is, there will be a campout up in the space station for awhile.

  • I have an easy solution... (Score:3, Funny)

    by jo7hs2 ( 884069 ) on Saturday April 29, 2006 @03:46PM (#15229086) Homepage
    Spray the external fuel tank with a thick coat of EZ-Cheez. The incredibly high fat content should insulate the tank nicely, and any debris will just leaving cheeZ-ee marks on the side of the shuttle That way, it will really look like it has been around geeks. Some soda stains might help.

  • Here's an idea (Score:5, Interesting)

    by Opportunist ( 166417 ) on Saturday April 29, 2006 @04:12PM (#15229178)
    Have the guy responsible for shuttle safety fly with 'em. I hold any bets that those shuttles will be safer than driving through downtown NY rush hour... bad example.

    But I guess you get the idea.

    • Have the guy responsible for shuttle safety fly with 'em. I hold any bets that those shuttles will be safer than driving through downtown NY rush hour

      Or indeed get a politician to ride in one.

      Rich.

    • The engineers and the astronauts work hand-in-hand. I doubt that the engineers will be anything less than absolutely miserable if anything happened to the vehicle and crew. That said, the astronauts willingly assume the risk so as to further scientific progress. The engineers won't let them down if they can help it.

  • managing risk is art and science (Score:3, Insightful)

    by deltacephei ( 842219 ) on Saturday April 29, 2006 @04:34PM (#15229259)
    It's easy to armchair quarterback NASA at this point, but it's probably safe to assume that there is overwhelming pressure to make the right decision and that the decision to postpone further tweaking has not been made lightly. Fundamentally this is coming down to pressure to get on with the show and determine if this risk is a showstopper or not. They've decided that they can take the risk, and in all likelihood it is just one of many risks that have probably kept both engineers and managers in overdrive discussion for months.

    The overall context is the station: shuttle is essentially a bottleneck. If shuttles can't get back to multiple flights per year, then we've got a problem. Soyuz and the Russian space program have literally saved NASA's ass in the past couple of years getting supplies up. For reasons most likely political, ESA has not been part of a solution, which is unfortunate and a separate topic. So given an unreliable shuttle program depending heavily on Soyuz, the painful decision to stop station construction and maintenance needs to happen. This makes the July launch akin to a make or break demonstration. If there is a serious problem, or another disaster, then NASA really can't look Congress in the face and make an argument for the station. Personally I haven't been able to make an argument for the station at all and would love to see a bare bones report of any sci/tech knowledge we've truly gained. As a long term reader of several NASA news listservs I see way too many fluff stories that are self congratulatory ("aren't we special? little joey dreamed of the space program his whole life and now he does X for NASA, let's all give him an internet pat on the back"), and not nearly enough along the lines of interesting experimental results or technology developments.
    • As a long term reader of several NASA news listservs I see way too many fluff stories that are self congratulatory ("aren't we special? little joey dreamed of the space program his whole life and now he does X for NASA, let's all give him an internet pat on the back"), and not nearly enough along the lines of interesting experimental results or technology developments

      I think you just summed up most government research...

    • The overall context is the station: shuttle is essentially a bottleneck. If shuttles can't get back to multiple flights per year, then we've got a problem. Soyuz and the Russian space program have literally saved NASA's ass in the past couple of years getting supplies up.

      Not really. Supply flights have been flying at exactly the same rate for years now.

      The bottleneck is in station construction - except for the vaporware Russian ones, all the remaining hardware has to ride the Shuttle.

      For reasons most li

  • It seems the only people who are really in a position to either complain or approve of these changes (morally) are the astronauts themselves. If they think the risk is worth the benefit of getting to fly earlier well who are we to say that they aren't making the right deciscion?

    I mean given how many safe flights the shuttle has made without the foam causing a problem, and given the extra in fight safety measures (cameras and stuff) that have been implemented it isn't clear that the foam is the biggest risk the astronauts face. Flying into space is a very risky, unsafe buisness especially on old equitment like the space shuttle. It would be a shame if the publicity of the previous disastor meant that we spent tons of money fixing the foam problem when the total risk could have been reduced more for the same money/time by fixing other safety issues.

    It is a general problem that things we have seen cause disastors seem more dangerous than those that have yet to cause any problems. However, we should not let that emotional effect get in the way of making the best safety choices. If the next shuttle blows up because we insisted on reducing the foam risk to 0 rather than doing a cost benefit analysis then the blood of the astronauts is on the hands of everyone who flipped out about the foam but wasn't going to care about other safety issues. On the other hand if fixing the foam really does decrease the risk the most per unit of money/time we than we bad better focus on that. However, as laymen the only thing we can do is trust the experts and second guessing them risks doing more harm than good.
    • Actually, the astronauts ARE in that position. They are fully briefed on these issues, and they have the right to say "I won't fly in that".

      Unfortunately, they are a very BAD choice of person to make the decision as to whether to fly at all, because they are typically very much risk-taking personalities, and many are likely to say "oh, so there's probably a 1 in 100 chance of a fiery death, but I get to go into space? Ok, let's do it!"

      While that may be OK for an astronaut on a personal level, every accide
  • There was a repair in the same location (and shape) as the peice that fell off. Many engineers at NASA feel that as long as that foam is undamaged/repaired it will behave as it should. Obviously the safest thing to do is to remove the foam, but they must ensure that it will not affect the aerodynamics adversly. Its a trade off. They know how the PAL ramp behaves, and have good reason to think that it won't shed.

  • slashdot exaggerating again (Score:3, Insightful)

    by heroine ( 1220 ) on Saturday April 29, 2006 @08:21PM (#15229971) Homepage
    The fuel tank is flying without the PAL ramp. The decision was not to continue removing sections other than the PAL ramp. They have to do as little as possible and test each change in a real flight to know what works.

  • I'd Simply Like to Point Out... (Score:5, Insightful)

    by dthx1138 ( 833363 ) on Sunday April 30, 2006 @06:22AM (#15231260)
    ... That many of you are assholes. I'm sure your physical science course at Ithaca Community College gives you the necessary qualifications to fix the entire shuttle program with a two sentence /. post.

    Give us engineers some fucking credit please.
  • Very strange side topic.

    I have been a slashdotter for around 8 years (I do have an ID in the 500,000s), and this is the first time in all that time that I have seen relatively insightful posts modded as "troll" or "overrated".

    As an automobile fan, who owns a '51 Merc, a '73 Nova, an '87 Buick Grand National, and a '03 Suburu WRX...

    YOU ARE ALL CAR IGNORANT!!

    Cars of today cannot be compared to cars of 10, 30, or 50 years ago.

    I have learned what I needed to know for each of my vehicles, and I f
  • The Falcon 1 addresses a related problem with a novel approach.

    The related problem was the rapid boil-off of LOX in the tropical heat. So they covered the LOX section of the booster with a thermal blanket, designed to fall away at launch with cables. Apparently, the blanket did get hung-up on the ill-fated first launch. But perhaps thi principle would be okay for the Shuttle. There's no reason the Shuttle needs to drag all that foam up into space. The only need for the foam was to protect against ice fo

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