the military has deep experience with smallish, relatively portable nuclear power plants -- see our submarines. Yep, and satellites, the types that keep going

the military has deep experience with smallish, relatively portable nuclear power plants -- see our submarines. Yep, and satellites, the types that keep going away and away. They are quite often nuclear powered, to run on-board electronics, but not the reactor type though. Hmm, I wonder what if somebody can make a hydrocarbon with a hyper calorific density, couple it with a high specific output IC engine, electric motors, put on regenerative braking and then batteries with the highest energy density?