The reason is that there is no need for crews or for a staff at the dump to have a place to “stretch their legs”. Nor is there any advantage to have a vast stockpile of fuel ‘just in case’, you might as well launch it as needed. Most of the reasons to have a dump irl do not appear to be true in space. And the rocket equation means you pay in mass fractions regardless of scale.
Hmm, without knowing what the reasons for fuel dumps are, I can’t tell how convincing those points are. I am not very convinced myself. Off the top of my head here are some reasons you might want an orbital fuel depot:
--You are limited to certain windows of opportunity for launches, or perhaps you are pad-constrained, or both. So you can’t just launch a fleet of tankers alongside your regular ships; it pays to spread out the launches, and have tankers go up when regular ships don’t need to, and then regular ships can go up and have fuel waiting for them already, anytime. (I guess this is an objection to your “might as well launch as needed” claim.) (I think this is the biggest reason; currently it takes several tankers to refill one starship I think, which means you either have to launch all of them at around the same time as the starship, or you have to have the starship wait around for one tanker to fly up and down and up and down. Might not be feasible given launch pad and launch window constraints.)
--Your tankers aren’t optimized for holding onto fuel in vacuum or for long periods of time, or maybe they aren’t optimized for transferring it quickly to other kinds of ships. So you build a depot that is.
The second part—you basically need a solar power gas recondensor. Or to have one onboard. I take your point, fuel refrigeration is a role that you might not have ships do and you could keep a module in orbit to do.
But the hassle of docking and maintenance—and possibly zero net cost savings—might make it cheaper to just launch fuel condensing modules on be vehicle for the mission itself.
The reason is that there is no need for crews or for a staff at the dump to have a place to “stretch their legs”. Nor is there any advantage to have a vast stockpile of fuel ‘just in case’, you might as well launch it as needed. Most of the reasons to have a dump irl do not appear to be true in space. And the rocket equation means you pay in mass fractions regardless of scale.
Hmm, without knowing what the reasons for fuel dumps are, I can’t tell how convincing those points are. I am not very convinced myself. Off the top of my head here are some reasons you might want an orbital fuel depot:
--You are limited to certain windows of opportunity for launches, or perhaps you are pad-constrained, or both. So you can’t just launch a fleet of tankers alongside your regular ships; it pays to spread out the launches, and have tankers go up when regular ships don’t need to, and then regular ships can go up and have fuel waiting for them already, anytime. (I guess this is an objection to your “might as well launch as needed” claim.) (I think this is the biggest reason; currently it takes several tankers to refill one starship I think, which means you either have to launch all of them at around the same time as the starship, or you have to have the starship wait around for one tanker to fly up and down and up and down. Might not be feasible given launch pad and launch window constraints.)
--Your tankers aren’t optimized for holding onto fuel in vacuum or for long periods of time, or maybe they aren’t optimized for transferring it quickly to other kinds of ships. So you build a depot that is.
The second part—you basically need a solar power gas recondensor. Or to have one onboard. I take your point, fuel refrigeration is a role that you might not have ships do and you could keep a module in orbit to do.
But the hassle of docking and maintenance—and possibly zero net cost savings—might make it cheaper to just launch fuel condensing modules on be vehicle for the mission itself.