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NASA Probes Shuttle Oxygen Leak

Posted by ScuttleMonkey on from the getting-started-with-a-bang-not-necessarily-a-good-thing dept.

Cherita Chen writes "NASA is investigating the possibility of a gaseous oxygen leak, posing a serious fire risk, during the launch of the space shuttle Discovery in July. From the article: 'Engineers uncovered possible evidence of high concentrations of the gas in the rear engine compartment about two minutes after lift-off. A leak could lead to a fire or even an explosion in flight.'"

9 of 150 comments (clear)

  1. some comments by ls+-la · · Score: 1, Interesting

    NASA is investigating the possibility of a gaseous oxygen leak,

    If it's leaking into the atmosphere it's going to become gaseous very quickly anyway.

    posing a serious fire risk... evidence of high concentrations of the gas

    High concentrations of oxygen won't combust, it's the lower-middle concentrations (especially mixed with certain other chemicals) you have to watch for.

    Well, at least NASA's engineers are finding the space shuttle's flaws, even if they're not FIXING them.

  2. 500 parts per million? by Lord+Byron+II · · Score: 4, Interesting

    What is the significance of the 500 parts per million figure in the article? What is the rest of the gas made up of? As a reminder, normal air is 20% oxygen, or 200,000 parts per million.

    1. Re:500 parts per million? by RayBender · · Score: 4, Interesting
      The engine compartments are filled with pure N2 to prevent the possibility of fires. 500 ppm of O2 is quite small, but it shouldn't be there at all - clearly something is not right...

      By the way, the inert-gas fill of the engine spaces has caused problems - I think a couple ground crew were killed some years back when they entered the spaces before they had been properly vented.

      --
      Human genome = 3 billion base pairs = 6 GBit. Windows + Office = 20 Gbit. Which is more impressive?
    2. Re:500 parts per million? by rand.srand() · · Score: 2, Interesting

      That's a good question. The inside of the rear cabin is vented shortly after lift-off, so it's not as if they expected to find none, they just found more than they expected. This indicates a leak or an instrumentation issue (one of the leak detection bottles failed to function at all), but keep in mind the SSME's have a pretty decent history of leaking from all sorts of places to the point of early engine shutdown (STS-93).

      It sounds to me like NASA is trying to kill off the shuttle... even the most esoteric engineering problems make headlines these days.

    3. Re:500 parts per million? by greensasquatch · · Score: 3, Interesting

      Isn't ppm a percentage, shouldn't 200ppm at sea level be the same percentage of oxygen as 200ppm at altitude (just fewer molecules). Or is this not how the sensors are calibrated.

  3. what else could go wrong? by radical_dementia · · Score: 2, Interesting

    So they found out about a potential serious problem 2 minutes after liftoff and they said nothing until 5 months later? Seems to me that NASA is trying to save face and not doing a good job at it. I've always been a strong supporter of NASA, but enough is enough, they just keep dumping billions of dollars into the space shuttle program and nothing constructive is happening.

  4. Re:Scuttle the Shuttle by drinkypoo · · Score: 4, Interesting
    Dude, they knew all this before they even fucking built it. The Shuttle was a decent (if suboptimal) design before the military got at the specifications. It had to carry and be able to deploy cargoes of a certain size to get the write-off from the military.

    The shuttle was supposed to be a prototype and we were supposed to move on. Instead, we got the shuttle, and it was "good enough" so we hung on to it. The fact that we A> discard the main tank, B> have to totally rebuild the SRBs, and C> have to rebuild the main engines, and all of this for each flight makes it just as cheap (if not cheaper) to use rockets as compared to the shuttle. The only thing the shuttle has that rockets don't is that it can be used to bring things back from space. Well, if those things are the right size and shape for the cargo bay, anyway.

    --
    "You're right," Fisheye says. "I should have set it on 'whip' or 'chop.'"
  5. Re:And it makes me wonder... by eldavojohn · · Score: 2, Interesting

    A flawed analogy doesn't convince me, sorry, you'll have to try harder than that.

    Just because something is old doesn't mean it's obsolete. Nose cone fuselage shapes have remained the same.

    *sigh* I guess I'll fight bad analogy with bad analogy.

    Why are we still using the same electic engine design (thank you, Tesla) for all these years? It's akin to using the steam engine to power cars in 1960.

    Why don't you close your analogy and tell me what advances we have made in shuttle protection that are as serious as the contrast between a freaking jet engine and a tiny motor?

    --
    My work here is dung.
  6. Hmmm, how likely is this? Very, but risk is small by Ancient_Hacker · · Score: 2, Interesting

    Lesse, we have a heat engine turning hundreds of gallons per second of cryogenic liquids into heat, then into a bazillion horsepower, a fair percentage of which gets turned into vibration. What are the chances of a bolted flange working loose, or a pipe fracturing, or a short temperature imbalance warping a pipe, valve, seal, or flange? What are the chances some piece of paper or other material was left in a hot zone, and the oxygen is just being boiled off the object? 500ppm is miniscule-- you can't get a flame or explosion until the fraction gets 100's of times higher. And a lot of the compartments are filled with inert gases, so it's even harder to start a fire.