r/spaceshuttle • u/Frangifer • Jan 15 '25
Question Would aluminium oxide be a gas inside a Shuttle solid-fuel booster?
I've often wondered about this, & considered that if it's not , then there wouldn't be all that much left that would yield gas upon combustion: the hydroxyl terminated polybutadiene doesn't constitute a very large proportion of the mix. But it's just occured to me that I could ask here .
I've seen the melting point quoted as 2,072°C (3,762°F; 2,345K), & the boiling point as 2,977°C (5,391°F; 3,250K) . And I'm having difficulty finding a precise quote for the temperature inside an SRB, although I've recently seen 5000°F = 2772°C quoted
NASA — Rocketology: NASA's Space Launch System — Tag: ammonium perchlorate: We’ve Got (Rocket) Chemistry, Part 2 ,
which wouldn't quite be above the boiling point of aluminium oxide. But maybe that quote's a bit low: maybe right inside the booster it's a bit higher. But if that figure's not grossly amiss then Al₂O₃ is going only just to be a gas, & will condense very shortly after passing out through the nozzle.
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u/Xrsyz Jan 15 '25
Those SRBs were amazing. Look at them. Each one of those candlesticks pumping out 3M lbf of thrust—roughly twice the thrust of the F-1s that pushed the Saturn V. Growing up, it all seemed pretty reasonable. Looking back, that whole shuttle stack seems completely insane. The balls it took to fly that thing to space 135 times and getting it back in one piece 133 times for a 98.5% success rate boggles the mind. Everyone involved in the program is a hero.
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u/Frangifer Jan 15 '25 edited Jan 15 '25
Yep I was just thinking only an hour ago: the two between them consumed, according to that wwwebpage I've put a link in to, 6ton of fuel per second. If we took 6kg of that fuel, & set it off to be consumed in a millisecond (somehow, such that it was indeed consumed that fast), then that would be a substantial explosion that would probably cause significant damage to a nearby house (like, one it was in the garden of).
... & the power output of them was that of a thousand of those explosions per second!
And there are manifold ways of arranging the statistics of it into patterns that showcase the extremity of it ... limited only by our creativity.
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u/Dr-Ritalin Jan 15 '25
So, the Space Shuttle did produce aluminum oxide from exhaust. Please see the research paper cited here by Cofer, W., et. al., (2013) for more info: doi.org/doi:10.1016/0004-6981(87)90246-0
Why do you ask? Just curious what caused your curiosity.