Nuclear is used in space, but my understanding is that it is too low power and not really scalable to computing needs for this use case. Bonus side really is that nuclear power can provide power for very long time.

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adrian_b 2 hours ago | parent [-]

Until now only energy sources based on radioactive decay have been used in space, which have very low power, but they can provide it for many decades.

Nuclear fission reactors, similar to those used on submarines or ships, would enable very different applications.

Until now, they have not been used for fear of what would happen after a failed rocket launch, when the reactor would fall back on Earth.

This could be mitigated by sending only components of the reactor and assembling it in space.

I do not think that routine exploration of the Solar System beyond Mars will ever be possible without using at least nuclear fission reactors, because it is too slow with chemical sources of energy.

	▲	echoangle an hour ago \| parent [-]
		Actually in the Cold War there were some actual nuclear reactors in space: https://en.wikipedia.org/wiki/TOPAZ_nuclear_reactor#TOPAZ-I > This could be mitigated by sending only components of the reactor and assembling it in space. How would that help? The main problem if the launch fails is that the radioactive material will spread around (in the worst case, they are encased so exactly that doesn’t happen). You could maybe spread out the nuclear material in multiple launches but you would just increase the risk of a small contamination in exchange for a smaller risk of a large contamination. I don’t think the individual parts of the reactor are intrinsically safer than the reactor, it’s not like it’s going to become an atomic explosion during launch.