- "For example, if we need a gigawatt of energy (10,000 people at 100 kW each) and space reactors weigh ( https://en.wikipedia.org/wiki/Kilopower https://en.wik

- "For example, if we need a gigawatt of energy (10,000 people at 100 kW each) and space reactors weigh ( https://en.wikipedia.org/wiki/Kilopower https://en.wikipedia.org/wiki/Kilopower ) 150 T/MW, we’ll need to salami 150,000 T of reactors between 1500 Starship flights..." The example he's drawing on (NASA's Kilopower concept) is a 10-kilowatt sized reactor and it's probably a bad extrapolation to scale from that to the 1-gigawatt scale, linearly. This is at least a 50-fold overestimate of mass. From nuclear electric propulsion literature [0], the mass budget for space electric power plants at the 15-megawatt scale optimizes to around 3 tons / megawatt. (I couldn't find serious engineering studies at the gigawatt scale). [0] https://inldigitallibrary.inl.gov/sites/sti/sti/2688772.pdf https://inldigitallibrary.inl.gov/sites/sti/sti/2688772.pdf ("Multi-Megawatt Power System Analysis Report" (2011)) (Mainly, the closed Brayton power systems summarized in table 4, on page 26)