That's often mentioned but there's a bit of a problem there. If you can get net power from fusing He3, then you can also get net power from the easier D-D react

That's often mentioned but there's a bit of a problem there. If you can get net power from fusing He3, then you can also get net power from the easier D-D reaction, and the waste product of D-D is....He3! Half directly, half as tritium which decays to He3 with a 12-year half-life. Even though D-D emits neutrons, they're at an energy similar to fission neutrons, rather than the extremely energetic (and easiest) D-T reaction. It's almost certainly going to be cheaper to get your He3 from D-D fusion, and get energy in the bargain, rather than sifting through millions of tons of lunar dirt. Fusion startup Helion, funded in part by YCombinator, is working on a hybrid D-D/D-He3 reactor, saying the combination will produce only 6% of its energy as neutron radiation, compared to 80% for D-T.