On reusable motherships

[rpayne88]

Would it make sense for the human race to make a REUSABLE mothership for manned exploration of the solar system. Originally, I thought that would be the only way to go. I mean, if you spend several billion dollars building the thing, why should you not leave the thing in LEO and ferry crews and supplies to it? But this got me thinking, would it have exceeded its lifespan while completing its first mission? Would the current level of technology on Earth be on par with the technology aboard the ship?

The big question is, should we make an expendable ship rather than a reusable one due to the costs, since it would probably be cheaper to build a new ship.

[Warhorse]

I think that as long as we are limited to chemical propulsion, expendables are the only thing that makes sense. There's no point in hauling a lot of empty tankage any further than you have to, chemical rockets just don't have enough power. Once we graduate to something better (nuclear? ion? solar sail?) the answer will depend a lot on how reliable the engines are, and how much maintenance they require.

[Genius Evil]

With current rocket technology, a single stage interplanetary craft would be impractical, so most of it will be left behind. It might actually be more expensive to send a reusable habitat on two interplanetary trips than to just launch a new habitat, because a reusable habitat would have to be able to survive at least twice as long as a single-use one. The cost of launching the extra fuel for the higher-mass reusable habitat would probably balance out the savings.

[Krevsin]

With chemical rockets, using the Mars Direct route would be the best.

And even otherwise, maintaining a large craft in orbit for several years of constant wear and tear (even moreso than the ISS, because a mothership would have an engine and quite possibly a heatshield) isn't exactly economical without cheap space access, so it'll be a while before a reusable mothership may become reality.

[Godot]

Even for KSP it makes more sense to design rockets/spaceships with stages instead of having a reusable mothership that has to be supplied by tank ships (thereby imposing an additional fuel cost to the transpoted fuel due to the fuel the tanker ship has to use to get to the mother ship [and maybe back to Earth/Kerbin]).

And this even without KSP simulating wear and tear, like mentioned by Krevsin

[ANWRocketMan]

It would only become viable if Career mode with a monetary system comes along. Unless you're role-playing. Everything is better with role-playing!

[B787_300]

For Real life it currently does not make sense. For a Mothership with our current technology would be outdated within 4-5 years. The way around this is to make the ENTIRE thing modular, but that adds more expense and engineering complexity, plus you have to launch the new modules into space, which is expensive. So until we have almost completely reusable crafts capable of going from earth to LEO for cheap, it makes no sense

[3_bit]

It all really depends on how often you're using it and what maintenance costs are, turnaround time, etc.

The Proton rocket is still in use today after several iterations, because it's reliable and fairly cheap. The fact that it's practically as mass-produced as a rocket can be is why it is this way. Now if we could mass-produce reusable rockets, then you'd have yourself a multi-billion dollar industry, as well as revolutionizing space travel as we know it.

[SargeRho]

Rapid turnaround SSTOs or reusable rockets will be pretty much required for a mothership to be feasible. But we'll also need more efficient engines. Fusion Driven Rocket, MPD thrusters, etc.

[Nuke]

nuclear/fusion reactor and mpd would be sexy for this kind of application. but i have a feeling that with current attitudes towards launching nuclear reactors into space, this wont happen until we have small, light, fusion reactors (like polywell or dpf). we might also end up with pure fusion engines that means we dont need no reactor. having a power reactor does have other advantages, powering centrifuges, hydroponic gardens and other life support hardware, could be possible to sustain life in space indefinitely at that point.

[NGTOne]

I heard somewhere about the Russkies and the Americans teaming up to send some of the old ISS components (and some new ISS-derived hardware - basically, the bits they didn't use for OPSEK) as a mothership to Mars. Not sure how far that got past conceptual, though. Not 100% sure where I heard it, though.