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t1_j6lb24j wrote

Reply to comment by in NASA tested new propulsion tech that could unlock new deep space travel possibilities by

> nuclear-powered spacecraft, which would allow spacecraft to travel further distances without needing liquid fuel

Nuclear thermal rockets still use a liquid fuel. There still has to be some mechanism for momentum transfer, and that means shooting something out the back of the rocket really fast.

Specifically, NTR thrusters use hydrogen superheated from passing over a nuclear reactor. Exhaust velocity of tested variants from the 60s and 70s were up to roughly twice the exhaust velocity of typical chemical propulsion systems.

The disadvantages are the ones you’d expect: putting a nuclear reactor on top of a giant controlled explosion is risky, and mounting a nuclear reactor makes the engine weight significantly higher so thrust to weight ratios are much lower. Still, it’s expected they would provide a significant performance advantage if engineered to fruition.

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t1_j6ltpxi wrote

Nuclear propulsion would likely need to be assembled in space and when needed, the spacecraft would need to attach to it in orbit. Critical malfunction tends to happen in atmosphere.

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t1_j6me6b0 wrote

Hey I'm the guy that approves this shit, I'm not at my desk right now so if you guys could just go ahead and get started that would be great.

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