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by Gravityloss 42 days ago
Actually... Rockets don't use thermos bottle tanks. Having two surfaces with a vacuum in between, like in a thermos bottle, would be way too heavy. That's why you see these chunks of ice falling at liftoff from cryogenic rockets.

Centaur has balloon tanks which is just very thin metal. It can't even stand on its own without pressure. But no thermos.

1 comments

I wrote "thermos" in quotes because that's how Burke referred to the propellant tanks.

That said, on the Titan IIIE at launch, there was an second outer surface around the Centaur -- the payload fairing -- which was discarded only after atmospheric pressure was low enough that it was no longer needed to protect the payload and the Centaur upper stage. (It wasn't a true thermos as the space in between wasn't sealed and was at ambient pressure at launch).

See the cutaway views on pages 16 and 17 (pdf pages 19-20) of https://www1.grc.nasa.gov/wp-content/uploads/TC-6-Voyager-Fl...

Yes, sorry, my criticism was meant to be directed at Burke, since the thermos comment has always bothered me.

You're correct about payload fairing. Also, Space Shuttle External Tank was spray foamed, causing the Columbia disaster when a piece of foam from the tank with hit the wing leading edge. I was googling for what the final verdict was but couldn't easily find an answer. Nice summary in [1]. Cryogenics are complicated.

1:https://idlewords.com/2003/08/things_i_have_learned_about_fo...