[Spaceships] getting into orbit without superscience?

[Fred Brackin]

Originally Posted by Gnaskar

T
Space elevators on Earth might be extremely heavy, ranging from 17ktons to 1.6Mtons, depending on available tensile strength. On other worlds, they can be significantly lighter. We might be imagining very different things when we say "colony", but for me investing 10 ktons into orbital infrastructure is a sensible thing for a colony to do.



I'm not assuming a launch platform first stage, like the ones we have today. I'm talking a full blown rocketplane stage with 10 times the mass of the upper stage and 70-80% propellant. Somewhere in the 3-4km/s delta V range, off the top of my head. And that's assuming methane/lox or hydox. If metallic hydrogen is available, it can do far better. Though even with methane/lox, it would be an SSTO with 10% cargo on a Mars sized world, so it's plenty capable on its own.

.

For the space elevator it was the tramp frieghter bringing one with them that I believed the weight to be too high.

If you're actually planning a giant hypersonic rocket-powered seaplane that is the point where my suspension of disbelief fails. It'd be a _lot_ easier to build one really long runway like KSC has/had for the shuttle than it would be to build a hypersonic boathulled flying machine.