There are more efficient propellants than hydrolox, but extremely toxic [1]. With a bigger planet, we would have been forced to use either those or nuclear prop

There are more efficient propellants than hydrolox, but extremely toxic [1]. With a bigger planet, we would have been forced to use either those or nuclear propulsion to get to space. 1 - https://space.stackexchange.com/questions/19852/where-is-the-lithium-fluorine-hydrogen-tripropellant-currently https://space.stackexchange.com/questions/19852/where-is-the...