Bring back hydrogen lifting gas

Re:Bring back hydrogen lifting gas by londons_explore on Monday August 09, 2021 @03:45PM (#28121465)

There is a big benefit... Rocket nozzles that are most efficient in a vacuum don't work at sea level (oscillations cause the whole thing to shake apart). Therefore launching from high up means you can skip the less efficient rockets and just have a single type of more efficient rocket engine.

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Re:Bring back hydrogen lifting gas by sfblah on Monday August 09, 2021 @03:51PM (#28121560)

This is a very interesting point. Is there a counterargument to this?

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Re:Bring back hydrogen lifting gas by onethought on Monday August 09, 2021 @06:10PM (#28122951)

Vacuum optimised rockets require a vacuum. Balloons require atmosphere… so there is a gap where the balloon can’t go higher and the engine isn’t in vacuum yet

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Re:Bring back hydrogen lifting gas by imtringued on Tuesday August 10, 2021 @10:16AM (#28129142)

Combine balloons with skyhooks. https://www.youtube.com/watch?v=dqwpQarrDwk

Edit:

According to proprietary imtringued numbers the hydrogen for a balloon capable of lifting 1kg to 50km would be $800 if you do not reuse the hydrogen. The skyhook would accept vehicles at an altitude of 100km so no, keep balloons out of the space launch industry.

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Re:Bring back hydrogen lifting gas by londons_explore on Tuesday August 10, 2021 @01:32AM (#28125442)

Thin-atmosphere-optimized is a thing, and lets you get most of the benefits.

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Re:Bring back hydrogen lifting gas by lazide on Monday August 09, 2021 @08:31PM (#28123977)

Rockets use stages partially to solve this problem, also to deal with rocket equation issues.

So already a solved problem

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Re:Bring back hydrogen lifting gas by jasonwatkinspdx on Monday August 09, 2021 @10:06PM (#28124498)

1. Stages

2. Adaptive rocket nozzles are a thing.

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