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?

[AndrewEH1]

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

https://en.wikipedia.org/wiki/Assembly_of_the_Inte...

[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...

[slybynight]

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.

[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.

[Simpo Two]

Well, if the spaceship you need is bigger than what you can lift off the ground in one go, you have no option but to make it in bits.

[slybynight]

You need to build a solar system model - I'm always banging on about it on here! The nearest star is, so, so, so much further away than mars. I am also a bit of a "because it's there" type, but I have a horrible feeling that the manned lunar missions, put the tin lid on that type of thinking vs the costs involved :-(

[Eric Mc]

Modular spacecraft are quite common. With the exception of Skylab and the early Salyut/Almaz family nof stations, which were launched in one piece - most of the subsequent space stations (Salyut 6,7, Mir and now the ISS) have grown in size after the initial core module was placed in orbit. This was achieved by launching dockable add-on modules,

There is a good chance that when human craft do start venturing beyond low earth orbit, whether they are off to the moon, Mars or selected asteroids, they will have been assembled in earth orbit by modules launched separately.

Despite what others may say - people will be travelling to these destinations over the next 30 to 50 years.

[tactical lizard]

I take it you have a game called Kerbal space program if you like space so much?

[Eric Mc]

I like space but am not a computer gamer. I put my energy into reading about space flight and building scale models.

[Simpo Two]

slybynight said:

You need to build a solar system model - I'm always banging on about it on here!

That's easy. All you need is a football, an orange, a pea and a few other bits of fruit...

[davepoth]

Eric Mc said:

I like space but am not a computer gamer. I put my energy into reading about space flight and building scale models.

It may look cute but it's a hardcore space simulator at heart and is really very instructive in orbital mechanics - it has the seal of approval from NASA and Elon Musk so it can't be that bad.. There's a free demo on PC as well.

[Eric Mc]

I've had a look at it and may have a go someday - but I'm not that concerned about trying to work out how things are put into orbit. I have a working knowledge of all that anyway - at least, a knowledge good enough for me to understand the basic essentials.

I'm not knocking it in any way. In fact, I think it;s fascinating resource and a great way for getting younger folk who have the time and interest to "play" with it to learn how it all works.

I just prefer to do other things with my time on computers - like chat on PH

[xRIEx]

davepoth said:

Eric Mc said:

I like space but am not a computer gamer. I put my energy into reading about space flight and building scale models.

It may look cute but it's a hardcore space simulator at heart and is really very instructive in orbital mechanics - it has the seal of approval from NASA and Elon Musk so it can't be that bad.. There's a free demo on PC as well.

Love that game! I've learnt a huge amount from playing it. The only downside I can think of is, looking at games like Elite: Dangerous, No Man's Sky and those of a similar space travel style, I think "you can't just take off from a planet as simply as that!"

But like the suggestion above of putting an engine (or several) on the ISS, it makes you realise why it wouldn't work without planning for it from the start - centre of mass and centre/vector of thrust, how the CoM moves with fuel being burned, etc.

Edited by xRIEx on Saturday 23 July 11:54

Edited by xRIEx on Saturday 23 July 11:55

[slybynight]

Simpo Two said:

That's easy. All you need is a football, an orange, a pea and a few other bits of fruit...

In my model, the sun was a space hopper. The earth was a pea, about 150 yards away. The nearest star, in my model, was a balloon. In New York!

[Eric Mc]

Brian Cox likes table condiments.

[JagerT]

Wouldn't you just make it full scale ?

[xRIEx]

JagerT said:

Wouldn't you just make it full scale ?

I did. Are you enjoying it?

[Moonhawk]

patmahe said:

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.

Ignoring the ISS which has already been mentioned, NASA have been doing modular spacecraft assembly since early on in the space program.

The Apollo spacecraft were modular and had to be assembled in space. They had to dock the command module with the LEM because it wasn't in the correct configuration as launched.

The only difference between that and your suggestion is that all three parts were sent up on the same rocket.

[Eric Mc]

One of the original mission scenarios suggested for Apollo (and the initial front runner - favoured by Von Braun and his team) was to launch the Command Service Module on one Saturn V and launch additional fuel tanks on a second Saturn V 90 minutes apart. The two elements would dock in earth orbit and head off to the moon as a single craft. This original scenario had the Command Service Module fitted with legs and the entire craft would descend down to the lunar surface.

That's the reason why two Saturn pads were built (39A and 39B) and it's the reason why the VAB has a pair of doors - to allow two Saturn Vs top be assembled and wheeled out in quick succession.