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. …
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.
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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
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.
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.
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