I heard that Pu238 has limited production capacity. Apart from those widely discussed, I would be curious as of why these are rarely brought up: Pb210 is essentially Po210 with a longer half-life, which is more suitable for medium lifespan missions. How much Pb210 can be collected from a lead cooled reactor? Pu241 is essentially Am241, but it could give a slight power boost. Ac227 has a long decay chain which gives more (most?) power per atom. Any novel way for mass production? Cm242 is essentially Pu238, in addition to early power boost. Is it much harder to produce Pu238 this way? Pm147 has been discussed, but some sources give an unreasonably low power density (<1w/g) for its short half-life. Are they mistaken, or there is something I don't understand? My assumption is: spent fission fuel can be reprocessed promptly, further decay of daughter isotopes contribute to total power output.