to do anything useful in space we've got to get stuff there, i.e. heavy industrial machinery for mining That is what the Sea Dragon is for. The payload capacit

to do anything useful in space we've got to get stuff there, i.e. heavy industrial machinery for mining That is what the Sea Dragon is for. The payload capacity is 1.2 million pounds, and can be expanded with minor modifications. - It's only expensive and difficult now because we don't have anything with enough energy density to do it. We have kerosene and liquid oxygen. Chilled propane works, too. Are you thinking that these fuels and oxidizers are somehow not adequate? If so, in what way? - If you can make a powered re-entry you don't even need to bother with the Shuttle's elaborate heat shielding The Shuttle requires elaborate heat shielding for reasons that have nothing to do with the fact that it does not make powered re-entries. The Russian Soyuz capsule re-enters with a basic heatshield and lands on the Kazakh steppes. It's cheap. It's reliable. Powered re-entries to Earth are not feasible and not desirable. They would be outrageously expensive and probably unreliable (read: dangerous).