We can pursue high energy intensive activities with renewables, higher than if we use fusion.
On Earth, solar allows high energy use before we run into limits from direct thermal pollution, since it uses energy already hitting the planet rather than introducing new energy.
In space, the energy available from sunlight vastly exceeds any available from fusion, and the feasibility difference tilts even more toward solar.
For mobility in space, beamed power will be best, and solar works with that just fine, even out to interstellar distances.
I think there are a lot of in-depth trades that can be done to show specifically when nuclear is appropriate vs solar, and I'm sure solar will win a lot of those, but I'm just going to reach for the easy ones here.
Radio telescope on the dark side of the moon, using solar would require long transmission lines. Autonomous vehicles on Mars (already use nuclear energy via RTGs). Any deep space mission where building a nuclear reactor and launching it is lower effort than complex energy beaming.
I don't think a radio telescope uses much power at all. And beamed power should work fine on the night side of the moon, beaming power via laser from collectors in space. The apertures on either end would just be a few meters.
I have to question the moon as a location for such telescopes vs. positioning them in space. We've built (small) space radio telescopes already, but none have been placed on the moon.
On Earth, solar allows high energy use before we run into limits from direct thermal pollution, since it uses energy already hitting the planet rather than introducing new energy.
In space, the energy available from sunlight vastly exceeds any available from fusion, and the feasibility difference tilts even more toward solar.
For mobility in space, beamed power will be best, and solar works with that just fine, even out to interstellar distances.