Build a spaceship in orbit

[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.