back to article Things that make you go foom: Destruction derby as NASA and SpaceX test rocket components to failure

SpaceX popped another Starship tank yesterday as NASA prepared to conduct a final structural test of its SLS rocket. Elon Musk's rocketeers had patched up the prototype Starship tank, SN7, ahead of a round of testing to destruction. The hope was that the unit would make it past 7.6-bar mark, where it began leaking last time. …

  1. drand
    Coat

    I know this one

    "While Musk has yet to confirm how well the repairs performed and the pressure at which the failure occurred, it is unlikely that some duct tape will repair the damage this time around"

    In that case, they aren't using enough duct tape!

    1. hoola Bronze badge

      Re: I know this one

      Or the wrong duct tape.

      Has anyone else noticed how difficult it is now to get proper duct tape that sticks to anything, does not peal or tear when faced with a (not remotely sharp) object.

      There are so many cheap imitations on the shelves that the real stuff has disappeared because it was "too expensive".

      We used to use miles of the stuff in the flooring industry.

      1. This post has been deleted by its author

      2. Anonymous Coward
        Anonymous Coward

        Re: I know this one

        Duck tape and the superior gorrila tape are available in shops everywhere.

        I know, I use miles of the stuff to fix ford bumpers.

  2. Pete 2

    Hot LOX

    > The test will see the tank filled with water to simulate the liquid oxygen

    apart from the real contents of the tank being some 200°C colder in practice. As we would have hoped NASA had learned from the shuttle, materials behave differently when cold

    1. Stork Silver badge

      Re: Hot LOX

      One would hope they had tested material samples, incl joints, in the region around expected operating temperature.

      I did that sort of stuff using liquid nitrogen, even if we only really went down to -80C or so. Glass transition temperature of polymers if you want to know.

    2. bombastic bob Silver badge
      Boffin

      Re: Hot LOX

      good observation - I was going to comment on this.

      in short, metals are typically embrittled as temperature goes down. So failure at low temps is typically brittle fracture, which tends to be catastrophic. Ductile failure, at higher temperatures, can cause swelling before it finally bursts, but in essence the dynamics of the test change considerably when you drop temperature down to LOX levels.

      A fairer test might be liquid nitrogen to avoid explosive reactions with O2

      1. Anonymous Custard Silver badge
        Boffin

        Re: Hot LOX

        Oxygen actually liquefies at a slightly higher temperature than Nitrogen does, so you can use one to create the other (either deliberately or accidentally). So there is still some small risk, even if you use L-N2.

        Back in uni days it was one of the (many) demonstrations we used to do on school (and prospective student) open days. Take a large metal coffee jar (the kind that caterer supplies come in) and mount it at an angle using a retort stand. Fill it with L-N2 and after a while you'll get L-O2 condensing on the outside and dripping off the bottom edge. Stick something around the upper rim to deflect the N2 outflow forwards, and put a candle underneath the dripping L-O2. It's quite a nice demonstration of stuff like distillation and liquification.

        1. Robert Sneddon

          Re: Hot LOX

          In the UK you need a licence and government permission to buy liquid oxygen because it's regarded as a dangerous substance. You do not need government permission to buy gaseous oxygen and liquid nitrogen and narrow-bore copper pipe and...

      2. Stork Silver badge

        Re: Hot LOX

        This reminds me of a good story: Hardened steel tend to go brittle at higher temperatures than mild (aka carbon) steel. Some burglars therefore brought a styrofoam box and dry ice, and packed it around the troublesome lock parts and then gave it a whack with a hammer - worked a treat.

        My metallurgy teacher thought it was nice someone had listened.

  3. John Smith 19 Gold badge
    Unhappy

    People might like to note how long each programme has been going on.

    IIIRC it's taken about 16 years for NASA to get here.

    With SX it's been (I think I'm right in saying) less than 16 months.

    And in 16 months time where will they both be?

  4. Brangdon Bronze badge

    The robot dog

    The robot dog, Zeus, was seen poking around in the debris after the SpaceX test.

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