I think the capacity factor of nuclear is much closer to 95% or higher these days, but call it 100% for simplicity

PV capacity factor is typically 16%-28% [1], which adjusting the W/kg, gives us:

Solar PV: 0.8W/kg - 2.8W/kg, capacity factor adjusted (with supporting infrastructure weighing 2x the panels, a total spitball)

Nuclear: 0.8W/kg - 4.5W/kg, capacity factor adjusted, two different modern reactor designs, concrete only.

With this ratio, higher numbers mean better power densities, and the ranges completely overlap between nuclear and solar PV. Nuclear isn't achieving orders of magnitude better power density over solar.

[1] https://www.eia.gov/todayinenergy/detail.php?id=39832

You're still not adjusting for actual life (solar ain't making nameplate power 15 years in, for instance).

No one claimed an order of magnitude better. Nuclear looks somewhat more sustainable than renewable, and it can do some things renewables can't.

We should be doing both.

It's just so funny to read comments on here.

How can one even imagine a space-faring civilization powered by wind mills?

I suggest this is a problem with your imagination, not a problem with wind turbines.

Nuclear is a perfectly cromulant technology for space vehicles. It is not a good technology to power cities on earth in the 21st century however.