Build a spaceship in orbit

[MrrNeko]

Good evening.
As we know, we are currently limited with the shape of the ship to be as areodynamic as possible.

That is why I wanted to ask if we have the possibility of assembling a spacecraft in Earth orbit.

The assembly of the spacecraft could take place in orbit or in a specially prepared ISS module "covered dock"

Folding ships in orbit will allow us to create ships with better appearance and greater possibilities

[Jim]

Good evening.
As we know, we are currently limited with the shape of the ship to be as areodynamic as possible.

That is why I wanted to ask if we have the possibility of assembling a spacecraft in Earth orbit.

The assembly of the spacecraft could take place in orbit or in a specially prepared ISS module "covered dock"

Folding ships in orbit will allow us to create ships with better appearance and greater possibilities

Assembling would be harder on orbit.  Metal work in zero g would be difficult.  We don't have the logistics to support assembly on orbit.  That is what Starship is suppose to solve.

[TyOfNAARS]

Good evening.
As we know, we are currently limited with the shape of the ship to be as areodynamic as possible.

That is why I wanted to ask if we have the possibility of assembling a spacecraft in Earth orbit.

The assembly of the spacecraft could take place in orbit or in a specially prepared ISS module "covered dock"

Folding ships in orbit will allow us to create ships with better appearance and greater possibilities

Assembling would be harder on orbit.  Metal work in zero g would be difficult.  We don't have the logistics to support assembly on orbit.  That is what Starship is suppose to solve.

Aye, we would need a space port of some kind, in which it would be similar to NASA's giant VAB (Vehicle Assembly Building) but in space. Would need to be sealed & pressurized like the ISS (Or not). Cold-welding is a bit of a difficult problem in space.

For right now, most we can do is assemble a ISS-like ship. Module to module. We can develop a module that can contain an engine, which could then connect in to a computer system for control from a different module.

It's not impossible to build a spacecraft in orbit. Again, just as Jim stated, it's pretty difficult, as there would be a lot of different (And complex) problems to have to be figured out to have the capability in doing so, to something done regularly down the line.

I feel this would be necessary, especially if we're talking about having spacecraft powered by Nuclear Thermal propulsion or pulse propulsion. We could definitely get something going once we're on the Moon.

Somethin akin to this perhaps. lol

[r8ix]

Assembling would be harder on orbit.  Metal work in zero g would be difficult.  We don't have the logistics to support assembly on orbit.  That is what Starship is suppose to solve.

Starship is supposed to solve an entirely different problem. It just happens to solve that one, incidentally, on its way to solving its own problem.

[Jim]

Assembling would be harder on orbit.  Metal work in zero g would be difficult.  We don't have the logistics to support assembly on orbit.  That is what Starship is suppose to solve.

Starship is supposed to solve an entirely different problem. It just happens to solve that one, incidentally, on its way to solving its own problem.

No, the problem is cheap launch

[r8ix]

Assembling would be harder on orbit.  Metal work in zero g would be difficult.  We don't have the logistics to support assembly on orbit.  That is what Starship is suppose to solve.

Starship is supposed to solve an entirely different problem. It just happens to solve that one, incidentally, on its way to solving its own problem.

No, the problem is cheap launch

The problem is Mars. Cheap launch is part of the solution. Solves other problems as well.

[Jim]

The problem is Mars. Cheap launch is part of the solution. Solves other problems as well.

Wrong, everything is based on cheap launch.  Cheap launch enable Mars.  All other problems can be solved without cheap launch.  But without cheap launch, it doesn't matter if all the other problems are solved.

But Mars doesn't have to be part of the equation.  Cheap launch can exist without Mars. 

[r8ix]

The problem is Mars. Cheap launch is part of the solution. Solves other problems as well.

Wrong, everything is based on cheap launch.  Cheap launch enable Mars.  All other problems can be solved without cheap launch.  But without cheap launch, it doesn't matter if all the other problems are solved.

But Mars doesn't have to be part of the equation.  Cheap launch can exist without Mars.

<I>I</I> don’t disagree with you. But for SpaceX, the problem is Mars.

[hkultala]

<I>I</I> don’t disagree with you. But for SpaceX, the problem is Mars.

Mars is not a problem. Mars is a goal.

Too high launch cost is a problem for achieving the goal.

Starship is solution for the problem of high launch cost, to achieve the goal (Mars).

[tea monster]

High launch costs are the problem for just about any space endeavour. Why don't we have O'Neill colonies? Why don't we have solar power satellites? Why did it take us half a century to even talk about going back to the moon? Nobody could afford to pay for it.

If you reduce the cost to orbit by several magnitudes, then a lot more stuff becomes possible. Large businesses can start the ball rolling rather than just the most powerful nations on Earth. The dream of people living and working in space in large numbers can finally have a chance of happening.

Starship isn't a solution in itself to orbital construction. There is the argument that it will allow much larger parts of spacecraft to be lifted to orbit so that you need less launches to construct your on-orbit spacecraft. On the subject of an 'orbital shipyard', starship will make building such a facility much cheaper and easier, which increases the chances of someone who needs one to pull the trigger on making it.

[high road]

Good evening.
As we know, we are currently limited with the shape of the ship to be as areodynamic as possible.

That is why I wanted to ask if we have the possibility of assembling a spacecraft in Earth orbit.

The assembly of the spacecraft could take place in orbit or in a specially prepared ISS module "covered dock"

Folding ships in orbit will allow us to create ships with better appearance and greater possibilities

If you can't assemble the big ship without the dock, how are you going to assemble the dock? If you can build the dock, wouldn't it make more sense to use those techniques to assemble big ships in orbit without building a dock? Until you get to a point where there's enough demand for big things in orbit that makes the cost of building the dock smaller than any additional cost reductions from such a dock.

Edit: why not answer my own question while I should be working? Strong points. If you design the 'dock' to be able to handle massive loads practically everywhere, and outfitted to have a mobile arm move around on it to manipulate and anchor ship sections, anything built in that dock doesn't need to worry as much about construction methods and load bearing during construction.

This still assumes more than a handful of bigger ships in order to cover the cost, but far less than in my first assumption.

[Jim]

Why don't we have O'Neill colonies?
 

Don't need them

Why don't we have solar power satellites?

Won't work

[high road]

Even O'Neill said the only reason to build the first cylinders would be because that would make it cheaper to build massive numbers of SBSP platforms.

His assumed launch cost on Space Shuttle was off by a factor of 90. He only mentions the massive conversion losses once, and handwaves the difficulty of building an entire production process and supply chain to turn lunar silicates into SBSP platforms.

And, more on topic for this thread, he assumes it would be simpler in every imaginable way to do all that in microgravity or artificial gravity station rather than on the moon. That goes against all of our experiences on the ISS.

The point of this point was: the cost per kg on F9 is still a factor of five or six removed from O'Neill's assumption, and Starship will likely get to O'Neill's assumtion of 574.11$/kg (60 Space Shuttle launches for 1 billion dollars). But there are other major issues with O'Neill's vision that would need to be resolved before we ever see one.

[spacenut]

Building large spacecraft in orbit using 20 ton modules has already been proposed:

https://en.wikipedia.org/wiki/Nautilus-X

Nautilus X

Now with larger rockets coming on line such as New Glenn, Vulcan, and existing Falcon Heavy, 40 ton modules could be assembled in space to build a giant Nautilus X. 

Even with Nautilus X we still have to get in space refueling, fuel depots or such.  A capsule or landing craft for access to the Nautilus X.

Also, if going to the moon or Mars a large enough lander for return to orbit of a crew or to send down cargo for a base or colony. 

A refuelable Starship solves a lot of these problems, but it can also allow for a huge Nautilus X type craft to be built, or a revolving space station. 

[Vultur]

Why don't we have solar power satellites?

Won't work

Isn't it a matter of cost, not possibility?

I tend to think batteries are probably good enough now (and likely will continue to improve) that Earth-based solar would win out. But there might be scaling issues with doing battery storage on a "most of the world's power" level, I don't know if we'll know until it's seriously tried.

[JacobTheInvestigator]

It's difficult, but nevertheless, China plans to build its own space station in orbit and has already launched the first module into orbit..?

[spacenut]

It's difficult, but nevertheless, China plans to build its own space station in orbit and has already launched the first module into orbit..?

Much smaller space station than ISS.  More like MIR the Russians put up in the 1990's. 

[floss]

Much cheaper to build  large ships on the Moon and import the hard to produce items like microchips .
  Building in orbit is like building a castle on a mountain top really expensive and you have to import everything.

[tea monster]

Much cheaper to build  large ships on the Moon and import the hard to produce items like microchips .
  Building in orbit is like building a castle on a mountain top really expensive and you have to import everything.

That's the case - once you have a shipyard on the Moon. First you have to transport all the gear to build your shipyard and the workers who will build the shipyard and the parts of the ship itself, to the surface of the Moon. Then you have to provide it's workers with air, heat and food

What you are actually describing is carrying the parts to build your castle - and all the tools to construct it - up one huge mountain (Earth's gravity well), then carrying it over to a next door, smaller peak (the Moon's gravity well), and winching all your gear and materials down the second smaller mountain and building your castle in the valley of the second peak (the lunar surface). When you are done making your castle, you still have to lift it to the top of the second peak (lunar orbit).

I'm not saying that there won't eventually be shipyards on the Moon and in Earth orbit, but saying it's easier to do on the Moon when there is nothing but dust there at the moment is ignoring several large pachyderms in the room.

[floss]

Yes there is dust but it i mostly glass which can be used for structure. Neve mind the titanium and aluminium.

[tea monster]

Yes, once you have transported your factory, excavating and refining machinery as well as all your workers and their support systems up there.

[floss]

Extensive robots and virtual reality people only arrive when they are needed.

[jbenton]

Good evening.
As we know, we are currently limited with the shape of the ship to be as areodynamic as possible.

That is why I wanted to ask if we have the possibility of assembling a spacecraft in Earth orbit.

The assembly of the spacecraft could take place in orbit or in a specially prepared ISS module "covered dock"

Folding ships in orbit will allow us to create ships with better appearance and greater possibilities

Is this what you're getting at?:

https://www.youtube.com/watch?v=ir_SLjykvRE


In any case, it's actually quite surprising what will actually fit in a 5 meter fairing:

https://en.wikipedia.org/wiki/Magnum_(satellite)

https://www.youtube.com/watch?v=PCtye5TVonw

https://www.youtube.com/watch?v=f_eWC7OZx2E

https://www.youtube.com/watch?v=koUAvH9wkXA

https://www.youtube.com/watch?v=1Pm4MbIwRDw

EDIT: I forgot the most impressive one: the TransHab/BA 330 inflatable space station module. Oddly enough, I didn't find a good animation of a BA 330 expanding after being launched within a 5m fairing, so here's an animation from when before the TransHab ISS module was cancelled and transferred to Bigelow. It does a good job showing how it fits in a STS cargo bay and juxtaposing it to the largest rigid modules that would fit:

https://www.youtube.com/watch?v=uj-RPmgiE28

[Coastal Ron]

We built the 450mT ISS out of modules that weighed less than 16mT, and the ISS is still operational after 20 years, 7 months, and 17 days.

Here on Earth we do build large vehicles and vessels using modular construction, though things like ships and aircraft can be attached using techniques like welding that are not perfected for use in space. So building structures in space may have to accept not being as weight efficient as possible.

For a spaceship, the weight inefficiency would have to be made up by having bigger engines and using more propellant. But such efficiencies are typical for first generation transportation systems, so we shouldn't worry too much about that - focus on getting out there and learning what needs to be improved upon for the 2nd generation transportation systems! 

[KelvinZero]

Some improvements (as a fan boy) I would like to see over the way ISS was built.
* No need for spacewalks or people during assembly. Ideally we could assemble our ship/space-station anywhere in the solarsystem before crew arrive. Im not sure if that is difficult or if ISS assembly was designed to use spacewalks to make use of the shuttle.
* The ability to also disassemble a ship-station into its component modules again. Ideally you could maintain a station forever by simply replacing modules.. or you could retire a station and reuse modules for another purpose. My understanding is that some modules of the ISS could be reused/replaced but the central spine cannot
* Modules that are not just leaves off a tree but instead with more than one connection to other modules, or at least have additional struts so you could assemble multiple modules into something much more robust than a branch and leaf design... and this still has to be achievable without crew and possibly with significant time lag. Potentially this could also allow you to replace central modules without splitting the station into two parts.. though splitting a statiion into two parts and reassembling would be a nice to have also.

[high road]

Extensive robots and virtual reality people only arrive when they are needed.

So you extract, refine, cast, shape, assemble, etc all that material you came to the moon for, and build a launchable craft without extensive machinery? Seems to me having people up there loooong before the first ship gets built would reduce cost over trying to do alll of that without them. Nowhere near as low cost as launching modules from Earth, but still a lot cheaper.

[Rossco]

Personally I don't see us able to build a spaceship in orbit without some sort of artificial intelligence / robots to build them for us, something that can assemble the ship with minimal human interaction from the ground.

The only other way I can see is to have one built in modules using either the same as they built the space station or using inflatable modules delivered 'in orbit' multiples at a time, but then how much of that becomes more of a 'space station with engines' affair...

All of that is based on the assumption we can deliver the material to LEO in reasonably sort timescales, this would require multiple rockets, with fast turnaround times and regular (twice a month?) launches.

[RonM]

Personally I don't see us able to build a spaceship in orbit without some sort of artificial intelligence / robots to build them for us, something that can assemble the ship with minimal human interaction from the ground.

In LEO robots can easily be controlled from the ground. No new AI technology needed.

The only other way I can see is to have one built in modules using either the same as they built the space station or using inflatable modules delivered 'in orbit' multiples at a time, but then how much of that becomes more of a 'space station with engines' affair...

This is the easiest method based on current technology.

All of that is based on the assumption we can deliver the material to LEO in reasonably sort timescales, this would require multiple rockets, with fast turnaround times and regular (twice a month?) launches.

That's what SpaceX is working on, rapid access to orbit. Lower cost too. You don't even need that if you got money. Look how fast China is putting their space station together.

[Bryan Hayward]

That's what SpaceX is working on, rapid access to orbit. Lower cost too. You don't even need that if you got money. Look how fast China is putting their space station together.

The main reasons China is going so fast is:
1) they don't have to convince a legislative body to fund the project
2) they know it can be done (half the problem solved right there)
3) they have spend a lot of money on acquiring technology from other spacefaring nations (i.e. the USA)
4) they see it as a matter of national survival* and thus are spending a lot of money fast

*anyone who has read any sci-fi knows a space-faring nation is going to have an enormous advantage in conventional warfare, that is, not economic/informational/electronic

The only upside is the technology they are stealing is from when we did it the quickest, dirtiest, most expensive way possible.  If the USA values its advantage, SpaceX must be protected from espionage at all costs.

We need large, rotating (artificial gravity), overpowered (in the energy harvesting sense) space station (or three) for so many reasons.

1) national defense
2) research (astronomy, astrophysics, pharmaceuticals in the zero g sections, materials science etc.)
3) building more space infrastructure
4) building space ships
5) building space junk removal capacity
6) refueling depot
7) trans-shipment of people and cargo

[TrevorMonty]

Its possible to construct very large iron objects eg ship hull using Mond process.
Iron will bond with CO at low temperatures and turn into gas, at higher temperatures Iron drops out. By heating a surface you can control depth of coating.  Will need a mould with heaters.

Mond process needs a vacuum, which isn't problem in space. Neither is escape of the extremely toxic gas.

 This process was discribed in scifi book "Delta-V" by Daniel Suarez. Very good read and where possible he has used realistic processes for asteriod mining.



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[tea monster]

We don't know how to do large scale construction in space, apart from lego-style hab modules. If we are going to build a space economy, it is something we are going to have to learn to do. Using robots and improved spacesuit designs, it should be possible. A number of different methods have been proposed over the years. We just need to put our mind to it and work out the safest and most profitable way of doing it.

Just one thing that could come of this is cheaper satellites. Satellites are currently built to be completely autonomous for decades without any servicing. Imagine if satellites could be checked out at an orbital workshop before a robot space tug takes them up to their intended orbits. They could be built more cheaply if they could be snagged out of their service orbits by space tugs and returned to the workshop to be refueled and repaired.

Another is interplanetary probes, which could be checked out at the workshop before boosting to their destinations (no more Fobos-Grunt debacles).

[high road]

Not to mention being able to go through launch as securely packaged components, that can be assembled in space. Most of the satellite is structural mass that's no longer needed after launch.

It'll be a while before astronaut time becomes cheaper than launch cost though.

[Twark_Main]

We need large, rotating (artificial gravity), overpowered (in the energy harvesting sense) space station (or three) for so many reasons.

1) national defense

The idea that you need manned military space stations died back in the MOL days, didn't it? https://en.wikipedia.org/wiki/Manned_Orbiting_Laboratory

2) research (astronomy, astrophysics, pharmaceuticals in the zero g sections, materials science etc.)

This one's right.

3) building more space infrastructure
4) building space ships
5) building space junk removal capacity

4 and 5 are just special cases of 3. But the advantage of having manned systems (as opposed to using tele-operated robot arms) seem dubious at best.

We needed EVAs for ISS assembly mostly because all the electrical and fluid connections were outside the pressure hull. One of the big "lessons learned" from ISS is... don't do that.

6) refueling depot

No need for this to be manned. It only adds unnecessary risk.

Ideally your fuel and oxygen depots are both nicely separated from each-other, in addition to being separate from any manned space stations.

7) trans-shipment of people and cargo

Really another special case of 3.

Do we have any reason to believe this makes sense in space (ie something more than reasoning by analogy with terrestrial ocean shipping)?

[davamanra]

That's what SpaceX is working on, rapid access to orbit. Lower cost too. You don't even need that if you got money. Look how fast China is putting their space station together.

The main reasons China is going so fast is:
1) they don't have to convince a legislative body to fund the project
2) they know it can be done (half the problem solved right there)
3) they have spend a lot of money on acquiring technology from other spacefaring nations (i.e. the USA)
4) they see it as a matter of national survival* and thus are spending a lot of money fast

*anyone who has read any sci-fi knows a space-faring nation is going to have an enormous advantage in conventional warfare, that is, not economic/informational/electronic

The only upside is the technology they are stealing is from when we did it the quickest, dirtiest, most expensive way possible.  If the USA values its advantage, SpaceX must be protected from espionage at all costs.

We need large, rotating (artificial gravity), overpowered (in the energy harvesting sense) space station (or three) for so many reasons.

1) national defense
2) research (astronomy, astrophysics, pharmaceuticals in the zero g sections, materials science etc.)
3) building more space infrastructure
4) building space ships
5) building space junk removal capacity
6) refueling depot
7) trans-shipment of people and cargo

I agree with what you have said.  99.99% of what has been achieved in the Chinese space program has come from the efforts of all previous space agencies.  We've already done the R&D, gone through the trials and errors, made the mistakes, spent the money, and paid with lives.  You look at their space station right now and it's obviously just a Mir 2.0 with an ISS style robotic arm. 

As for the idea of building a spaceship in orbit, it is COMPLETELY doable.  It would be cost prohibitive, but that would be all. 
We have been assembling and disassembling stuff in space for 55 years.  In fact in many ways it would be better to assemble a spaceship in orbit.  You wouldn't have to worry about having some kind of robust structure to withstand the stresses of launch.  You could build a modular spacecraft that is held together by a lightweight frame and just launch the modules into space, then connect them together in space.  No fighting against gravity, no aerodynamic stresses, just piece them together like a big Tinker Toy set.     

[davamanra]

A supplement to my last post, https://forum.nasaspaceflight.com/index.php?topic=54238.0

This extensive study shows that this could have been done back in 1968.  After this there was, however, a lot of anti-nuclear sentiment so the NERVA part would likely be shut down, but when you consider the delta V of going to Mars is only about 35% higher than going to the Moon, chemical rockets could most definitely do it.  In fact, I have been working on a strategy that uses both EOR and MOR that could increase the safety of the mission through redundancy.  Granted, it would take a lot of extra hardware, but if we were producing Saturn V's on a production line basis, it could still be reasonably economical.

[TrevorMonty]

We don't know how to do large scale construction in space, apart from lego-style hab modules. If we are going to build a space economy, it is something we are going to have to learn to do. Using robots and improved spacesuit designs, it should be possible. A number of different methods have been proposed over the years. We just need to put our mind to it and work out the safest and most profitable way of doing it.

Just one thing that could come of this is cheaper satellites. Satellites are currently built to be completely autonomous for decades without any servicing. Imagine if satellites could be checked out at an orbital workshop before a robot space tug takes them up to their intended orbits. They could be built more cheaply if they could be snagged out of their service orbits by space tugs and returned to the workshop to be refueled and repaired.

Another is interplanetary probes, which could be checked out at the workshop before boosting to their destinations (no more Fobos-Grunt debacles).

Both Nanorack and Made In Space want to do satellite assembly in orbit. Likely to be robotic and maybe just 3d printing and attaching large structures like solar arrays and RF dishes. Satellite its self would be built on earth and sent to station on cargo vessel or on dedicated launch.



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[davamanra]

We don't know how to do large scale construction in space, apart from lego-style hab modules. If we are going to build a space economy, it is something we are going to have to learn to do. Using robots and improved spacesuit designs, it should be possible. A number of different methods have been proposed over the years. We just need to put our mind to it and work out the safest and most profitable way of doing it.

Just one thing that could come of this is cheaper satellites. Satellites are currently built to be completely autonomous for decades without any servicing. Imagine if satellites could be checked out at an orbital workshop before a robot space tug takes them up to their intended orbits. They could be built more cheaply if they could be snagged out of their service orbits by space tugs and returned to the workshop to be refueled and repaired.

Another is interplanetary probes, which could be checked out at the workshop before boosting to their destinations (no more Fobos-Grunt debacles).

Both Nanorack and Made In Space want to do satellite assembly in orbit. Likely to be robotic and maybe just 3d printing and attaching large structures like solar arrays and RF dishes. Satellite its self would be built on earth and sent to station on cargo vessel or on dedicated launch.



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Along those same lines is The Gateway Foundation and their robotic assembly strategy.  If we had something like that in orbit space exploration costs would plummet.  With launch costs decreasing it's just a matter of time before these two cost lines would intersect and  the cost/benefit would equal out.

[RoadWithoutEnd]

"Traditional" on-orbit assembly consists of very simple matings of complex systems built on the ground.  Detailed, high-skill, high-tech manufacturing in space is still far away because it would require putting a lot of industrial precursors in orbit, and also need interim applications for those precursors to justify their placement.

Nothing physically prevents building ships in space.  But in virtually all conceivable cases today, it's cheaper to build on the ground, launch the pieces in aerodynamic fairings, and then just assemble them in orbit as an end-product rather than doing OEM work in space.

That will change once there is a flourishing industrial base and supply chain offworld.

[Jim]

Imagine if satellites could be checked out at an orbital workshop before a robot space tug takes them up to their intended orbits. They could be built more cheaply if they could be snagged out of their service orbits by space tugs and returned to the workshop to be refueled and repaired.

Another is interplanetary probes, which could be checked out at the workshop before boosting to their destinations (no more Fobos-Grunt debacles).

Not really.  The ride on the tugs is no different than launch. What is going to check them out after that?  Most appendages and mechanisms can't be deployed until after the final stage.

[davamanra]

"Traditional" on-orbit assembly consists of very simple matings of complex systems built on the ground.  Detailed, high-skill, high-tech manufacturing in space is still far away because it would require putting a lot of industrial precursors in orbit, and also need interim applications for those precursors to justify their placement.

Nothing physically prevents building ships in space.  But in virtually all conceivable cases today, it's cheaper to build on the ground, launch the pieces in aerodynamic fairings, and then just assemble them in orbit as an end-product rather than doing OEM work in space.

That will change once there is a flourishing industrial base and supply chain offworld.

An important word there is "traditional."  Detailed high-skill, high-tech manufacturing IS too challenging in space, but there is a middle ground.  Send up the complex components from earth, but do the more rudimentary structural construction in orbit.  Use a certain degree of prefabrication on the ground, but do the bolting together in space. Obviously, the strategy would have to be worked out beforehand, but figure out which tasks would be better done on the ground and which tasks would be better done in space. 
   For example, to launch something into space, it has to be able to withstand the stresses of launch, but in space, doing fine detailed work is at the least challenging and at the most impossible.  At the other end, in space it isn't necessary for a structure to have to deal with the stresses of launch.  My example would be Von Braun's space station (yes I know it was never built, but the principle is sound.)  build a "delicate, lightweight" station in orbit, but use only a few pounds of easily installed cable as spokes to provide the station with structural rigidity.       

[high road]

Imagine if satellites could be checked out at an orbital workshop before a robot space tug takes them up to their intended orbits. They could be built more cheaply if they could be snagged out of their service orbits by space tugs and returned to the workshop to be refueled and repaired.

Another is interplanetary probes, which could be checked out at the workshop before boosting to their destinations (no more Fobos-Grunt debacles).

Not really.  The ride on the tugs is no different than launch. What is going to check them out after that?  Most appendages and mechanisms can't be deployed until after the final stage.

What prevents a slow and gentle boost to a  higher orbit?

[davamanra]

Imagine if satellites could be checked out at an orbital workshop before a robot space tug takes them up to their intended orbits. They could be built more cheaply if they could be snagged out of their service orbits by space tugs and returned to the workshop to be refueled and repaired.

Another is interplanetary probes, which could be checked out at the workshop before boosting to their destinations (no more Fobos-Grunt debacles).

Not really.  The ride on the tugs is no different than launch. What is going to check them out after that?  Most appendages and mechanisms can't be deployed until after the final stage.

What prevents a slow and gentle boost to a  higher orbit?

Nothing at all.  This is what makes ion thrust a viable propulsion technology in this capacity.

[Jim]

Imagine if satellites could be checked out at an orbital workshop before a robot space tug takes them up to their intended orbits. They could be built more cheaply if they could be snagged out of their service orbits by space tugs and returned to the workshop to be refueled and repaired.

Another is interplanetary probes, which could be checked out at the workshop before boosting to their destinations (no more Fobos-Grunt debacles).

Not really.  The ride on the tugs is no different than launch. What is going to check them out after that?  Most appendages and mechanisms can't be deployed until after the final stage.

What prevents a slow and gentle boost to a  higher orbit?

Time.   Was talking about interplanetary probes.   

Musk is going to use his starship.  That won't be slow and gentle.

[Coastal Ron]

Building large spacecraft in orbit using 20 ton modules has already been proposed:

https://en.wikipedia.org/wiki/Nautilus-X

Nautilus X

Now with larger rockets coming on line such as New Glenn, Vulcan, and existing Falcon Heavy, 40 ton modules could be assembled in space to build a giant Nautilus X. 

Even with Nautilus X we still have to get in space refueling, fuel depots or such.  A capsule or landing craft for access to the Nautilus X.

Also, if going to the moon or Mars a large enough lander for return to orbit of a crew or to send down cargo for a base or colony. 

A refuelable Starship solves a lot of these problems, but it can also allow for a huge Nautilus X type craft to be built, or a revolving space station.

I thought I'd bump this conversation back up, since it seemed like the only one that provided a solution that was achievable today.

The ISS is a 450mT modular structure that we built in space over 20 years ago, and we could build bigger. So if we needed to build something using near-term capabilities, a modular space craft could be built. How big it would be depends on its mission of course, so I won't speculate as to the size and shape, but "big" is possible.

Modular construction is not the most mass efficient, so there is a trade off between mass and construction complexity. But if we needed something built sooner rather than later, modular construction has been proven, and it would be fair quick to assemble in space.

[davamanra]

Building large spacecraft in orbit using 20 ton modules has already been proposed:

https://en.wikipedia.org/wiki/Nautilus-X

Nautilus X

Now with larger rockets coming on line such as New Glenn, Vulcan, and existing Falcon Heavy, 40 ton modules could be assembled in space to build a giant Nautilus X. 

Even with Nautilus X we still have to get in space refueling, fuel depots or such.  A capsule or landing craft for access to the Nautilus X.

Also, if going to the moon or Mars a large enough lander for return to orbit of a crew or to send down cargo for a base or colony. 

A refuelable Starship solves a lot of these problems, but it can also allow for a huge Nautilus X type craft to be built, or a revolving space station.

I thought I'd bump this conversation back up, since it seemed like the only one that provided a solution that was achievable today.

The ISS is a 450mT modular structure that we built in space over 20 years ago, and we could build bigger. So if we needed to build something using near-term capabilities, a modular space craft could be built. How big it would be depends on its mission of course, so I won't speculate as to the size and shape, but "big" is possible.

Modular construction is not the most mass efficient, so there is a trade off between mass and construction complexity. But if we needed something built sooner rather than later, modular construction has been proven, and it would be fair quick to assemble in space.

Not just ISS, but Mir  (and the Chinese space station Tiangong) used modular construction as well.  As a pet project, I have been designing an infinitely expandable space station concept utilizing The Skylab repurposing method, the WWS concept and a 6 point docking module based on the Mir concept.  My design uses Saturn 1B and Saturn V components with a docking point on one end, but if one wanted built a Salyut or Mir core style module, with docking ports available on both ends, then the versatility of the assembled design would only be limited to ones imagination.  It would be kinda like a tinker toys kit in space! 

[davamanra]

I was just watching a Youtube video and it was talking about cold welding in space.  This idea, properly implemented, can make assembly in space much less challenging. With the right equipment as well as our EVA experience, this has great potential.

[Jim]

I was just watching a Youtube video and it was talking about cold welding in space.  This idea, properly implemented, can make assembly in space much less challenging. With the right equipment as well as our EVA experience, this has great potential.

Actually, it makes the opposite and the strength is unknown.  Plus surface prep is hard.

[rubicondsrv]

Actually, it makes the opposite and the strength is unknown.  Plus surface prep is hard.

has there been an attempt to test this?  It seems like it would require impractically clean and smooth surfaces to be at all reliable.

I am mostly aware of work to prevent vacuum welding but have not heard of any serious attempt to use vacuum alone to reliably weld materials. 

All the repeatable methods of cold welding I am aware of use presses, hammers, or explosives to force the material together.   

[spacenut]

If SpaceX or NASA wanted to or had the money, a huge spaceship could be built in orbit using 100 ton modules with the Superheavy booster or even SLS.  Then FH could put up 40 ton modules in reusable mode and 60 ton modules in expendable mode. 

All other existing rockets could do 20 ton modules.

IF Vulcan gets it's engines I think it can do about 30-35 tons with the new upper stage it will have.

IF New Glenn ever gets built it can do 40-45 ton modules.

Module mass sizes are getting bigger with new ships, and cost may be coming down.  This may allow a large ship like the one on the movie Mars. 

The SpaceX system if/when they get all the bugs out might be more cost effective. 

[davamanra]

I was just watching a Youtube video and it was talking about cold welding in space.  This idea, properly implemented, can make assembly in space much less challenging. With the right equipment as well as our EVA experience, this has great potential.

Actually, it makes the opposite and the strength is unknown.  Plus surface prep is hard.

Actually I have thought of this and have considered some possible solutions:

First, The surfaces don't necessarily have to be perfectly smooth or rough, whichever the case may be.
Second, there is a technology call explosion welding, where two metals are joined through explosive impact.  I am envisioning something along the lines of nail gun but with no nail but a piston and on the other side would be a plate to contain the impact, the same way a stapler contains the impact causing the staple to curl itself under.
Third, in space the materials can be blasted with LCH4 which could dissolve and blast away any impurities.  Obviously as much prep as possible would be done on Earth, but this LCH4 prep could be done immediately prior to the "welding" process.
Fourth, this equipment can be designed to be used within the rudimentary motor functions of an astronaut on EVA. 

I don't deny there would be some trial and error necessary to find the optimal technique and materials.  Perhaps there might be a better solvent choice over LCH4, maybe even LH2 to break any oxide bonds on the surface, but once that is figured out, I see great potential.

[davamanra]

Actually, it makes the opposite and the strength is unknown.  Plus surface prep is hard.

has there been an attempt to test this?  It seems like it would require impractically clean and smooth surfaces to be at all reliable.

I am mostly aware of work to prevent vacuum welding but have not heard of any serious attempt to use vacuum alone to reliably weld materials. 

All the repeatable methods of cold welding I am aware of use presses, hammers, or explosives to force the material together.   

Precisely.  This is where this technique in conjunction with other proven techniques has the potential for making assembly in space a viable proposition.

[davamanra]

If SpaceX or NASA wanted to or had the money, a huge spaceship could be built in orbit using 100 ton modules with the Superheavy booster or even SLS.  Then FH could put up 40 ton modules in reusable mode and 60 ton modules in expendable mode. 

All other existing rockets could do 20 ton modules.

IF Vulcan gets it's engines I think it can do about 30-35 tons with the new upper stage it will have.

IF New Glenn ever gets built it can do 40-45 ton modules.

Module mass sizes are getting bigger with new ships, and cost may be coming down.  This may allow a large ship like the one on the movie Mars. 

The SpaceX system if/when they get all the bugs out might be more cost effective.

This is what I was thinking my happen.  Assemble a bunch of Starships in orbit like a big Tinker Toy set and then send them on to Mars (or the moon, but that might be overkill.)

[spacester]

On orbit construction of whatever technique is going to start with grabbing a starship payload from delivery orbit and transferring it to the construction orbit. A space tug, so to speak.

If you need eyes-on supervision, you need the tug to have life support. The more challenging the task, the more you will want human workers right there.

I can see incorporating a Dragon into a larger starship launched vehicle. It would have multiple robotic arms, solar power, and significant propulsion capability. It would need refueling and LOX. When not moving payloads to site, it would linger and assist in construction.

The critical part of building a spaceship in orbit seems to me the very first payload and how exactly you create a stable construction platform that gives you the ability to figure out how to do the thing with the things for the thing. Everything will be designed to be easy but it is space so everything will be hard, with exceptions.

[Roy_H]

Why don't we have solar power satellites?

Won't work

Isn't it a matter of cost, not possibility?

I tend to think batteries are probably good enough now (and likely will continue to improve) that Earth-based solar would win out. But there might be scaling issues with doing battery storage on a "most of the world's power" level, I don't know if we'll know until it's seriously tried.

Building solar power in space is already done to power the ISS and almost every satellite in orbit. But I guess you are talking about solar power satellites to give power on Earth. The cost of course would be many times building the same solar panels set up on Earth, but the main problem is transmitting that power back to Earth. If you try to do it with super power lasers or microwave the beam would destroy anything that might cross it's path, birds, airplanes, lower orbiting satellites. If you spread the beam out to be low and safe density you end up with an area not sufficiently smaller than solar panels on Earth to be worth while.

[StraumliBlight]

TechCrunch: Rendezvous Robotics exits stealth with $3M to build reconfigurable space infrastructure [Sep 10]

Instead of astronauts and robotic arms, Rendezvous is betting on autonomous swarm assembly and electromagnetism. The company is commercializing a technology called “tesserae,” flat-packed modular tiles that can launch in dense stacks and magnetically latch to form structures on obit. With a software command, the tiles are designed to unlatch and rearrange themselves when the mission changes.

“They find each other, they communicate … they arrange themselves, come together using magnetic docking and then latch together,” Landon said. “If you want to change that arrangement or replace something or upgrade, you can just send a command … unlatch, move over here, go into storage or come out of storage and we can change the arrangement.”

The current tiles are around the size of a dinner plate and roughly an inch thick, though the team envisions scaling tiles to the diameter of a rocket fairing. Each tile has its own processor, a variety of sensors, and a battery. These are “pretty simple” devices designed for mass manufacturing at low cost, Rendezvous CEO and co-founder Phil Frank said.

[...]

Looking ahead, the company is aiming to conduct a demo on the ISS in early 2026, followed by a mission outside the ISS in late 2026 or early 2027. That will be followed by “a real mission that shows mission utility,” Landon said, building an antenna aperture in space.

[Twark_Main]

Good evening.
As we know, we are currently limited with the shape of the ship to be as areodynamic as possible.

That is why I wanted to ask if we have the possibility of assembling a spacecraft in Earth orbit.

The assembly of the spacecraft could take place in orbit or in a specially prepared ISS module "covered dock"

Folding ships in orbit will allow us to create ships with better appearance and greater possibilities

Assembling would be harder on orbit.  Metal work in zero g would be difficult.  We don't have the logistics to support assembly on orbit.  That is what Starship is suppose to solve.

Aye, we would need a space port of some kind, in which it would be similar to NASA's giant VAB (Vehicle Assembly Building) but in space. Would need to be sealed & pressurized like the ISS (Or not). Cold-welding is a bit of a difficult problem in space.

For right now, most we can do is assemble a ISS-like ship. Module to module. We can develop a module that can contain an engine, which could then connect in to a computer system for control from a different module.

It's not impossible to build a spacecraft in orbit. Again, just as Jim stated, it's pretty difficult, as there would be a lot of different (And complex) problems to have to be figured out

Right. The trick is assembly in space, not manufacturing the pieces themselves. So you want to ship prefab components uphill and bolt / weld / glue them together.

For large monolithic pressure vessels you really want a standardized 3D "skeleton" grid that carries the tension, along with pressure bulkheads that act as interior (compartmentalization) or exterior panels.

Equipment is all prefab modules, snapped together.

Economically, the bar you have to clear is "does the freedom of design give you more savings than the in-space assembly adds in extra costs?"  Otherwise you can't compete with vehicles launched in one piece from the ground.