Soldiers of Tovias
hydrogen fuel cells
Hydrogen fuel cells are the reason that gas giants are so important. On a spacecraft, they are what provides power. missiles also use hydrogen fuel cells. Spacecraft require a refill of the hydrogen tanks after an extended use. Hyperspace engines run off of hydrogen tanks that are separate from the standard space flight engines to prevent a total loss of mobility. Hydrogen fuels cells are the reason that intergalactic space travel is still impossible.