Building a large scale modular spacecraft in space?

[patmahe]

Forgive me if this is a stupid question, I have a slightly higher than casual interest in space exploration but am not up to speed on all that is going on so its possible that this is being worked on and I'm just unaware of it.

But with all the work that space-x are doing on reusable rockets etc... it seems that soon it will get quite cheap to launch multiple rockets in quick succession.

So to my question, is it feasible that using these rockets, modular payloads could be delivered into orbit, or even to the surface of the moon and assembled there, meaning that the problem of getting a spacecraft off the Earth is no longer an issue. This means in theory there would be no limit to the size of spacecraft you could build and it would take relatively little power/fuel to take a large craft out beyond the moons orbit towards Mars or wherever you want to go.

I'm sure my question is wildly simplifying the issue but is this being worked on and if not why not?

[patmahe]

AndrewEH1 said:

The International Space Station is pretty much this, but over a longer time period.

I was thinking of that alright, so could they just strap an engine or 10 to that and go places in it. I'd imagine the work would be very hard for astronauts to do unless there was some form of pressurised mobile assembly area so they could work without suits etc...

[patmahe]

slybynight said:

I think he means - assembly of an interplanetary craft in orbit - ISS isn't going anywhere but down! It certainly makes all that sort of thing a bit more possible, but why would you bother? Mars is about the only realistic place to go isn't it? Colossally difficult (don't forget the habitat you'd need to take with you/have pre-deployed there) and what's the point? Other than some sort of life-boat insurance against us completely destroying this planet.

Ok but why did we go to the moon then? I'm very much of the 'because its there' mindset. Also we may make some discoveries by going there and push the edge of human knowledge that bit further.

Maybe a Mars mission is more viable, launching from Earth and just being careful about weight than building something in orbit and launching from space. But if we could potentially build something in orbit and explore the galaxy and be able to sustain a crew while doing so then why not do that, sure distances etc... are huge but there are some very clever people out there and different forms of propulsion may be viable in space that would be too big to launch from Earth in a conventional 1 rocket, 1 mission approach.