Speculation: Segmented Spin gravity habitat sized for launch in 2017 BFR Cargos

[TrevorMonty]

It sounds like the thread consensus is that in-space construction is a significantly better option than ground assembly and docking.

How much progress is being made on assembler robots? I saw the post on the spiderbot, but is it actually funded? What else is out there?

The current develops for in space construction are printing/assemble large light weight trusses or boom structures. This are for antennas, sunshades and solar arrays, persistent platforms. Besides building structure the robots will fit them out with cloth, solar panels, wiring etc.

I haven't heard about anybody working on systems to assemble large pressure vessels in space. This in way maybe easier as it would use precut metal parts that just need welding or fastening together. At present there is no market for it except on ground. As it happen the companies with lot of experience in this type of construction is LV manufacturers, look at how they stir weld SLS tanks together.

[Coastal Ron]

Some assembly required.

Unless you design your rotating station to be built using modules that are sized the transportation being used, some assembly (or even a lot) will be required in the hard vacuum of space. Not that it's bad to do that, just to point that out so that no one is scared about it - we did assembly on the ISS and it worked out OK.

Just as a suggestion, while the BFR/ITS is supposed to be 9m in diameter, and there is a cargo version that Musk showed off, designing your station to exclusively use the BFR/ITS may not be the best strategy. Could you build what you want if you designed everything to fit in the narrower Blue Origin New Glenn? It offers something close to 7m in diameter, and possibly much longer sections.

That way you would have two transportation systems that you could use, and that would ensure that you don't stop work if one of them shuts down their service for some reason (or doesn't want your business).

[TrevorMonty]

Thought bit more on how this construction could be done. Have curve platform  with robot arm with stir welder, bolt or clamp two section to platform then weld them together repeat till have complete cylinder section/ring. Now bolt or clamp two cylinder sections/rings together and stir weld the join. The one small welding platform which only needs to be big enough to hold two sections together, could assemble massive cylinders.

The sections used to create cylinder would all be identical allowing for mass production on ground or in distant future moon and asteriod mines.

Edited after reading Costal comments. Section sizes are designed to maximize LV lift capabilies. Mixing sizes is not big issue, one ring can be made from 20 sections while another could be 30 smaller sections, as long as same diameter doesn't matter. Ring width can be different, eg use 3 x  5m x30 section rings or 2 x 7.5m x 20 sections to create same 15m long cylinder.

[watermod]

I recall some long ago "research".   Maybe SBIR/STTR or the like that explored a steered and propelled device that extruded molten or glassy or plastic material on a structural flight path to provide girders or surfaces for a space structure.   Always liked the concept.

First example had some material like thermite melting aluminum or iron and extruding it in a stream while steering the extruding device in space. 

[Nomadd]

 BA-2100 concept. Each module about 8m stowed and around 100 tons if fully equipped, 70 tons dry weight.

[punder]

How do you dock with it?

Two hab modules, a docking hub, and a truss would make a "minimal" rotating facility with two levels of g, given an offset center of gravity. In my pic, the blue hab is for Lunar G, and the red hab is Mars g. (No, the distances aren't accurate, and I didn't include solar arrays, radiators and whatnot, but that's what you get for five minutes of work.)

Here is an interesting link: http://www.quantumworks.com/jbis_article.htm

[lamontagne]

A complex space build station, and a simpler assembled station, made from expandable units and extendable panels

[Lar]

I like the skylon in the second render...

[punder]

A complex space build station, and a simpler assembled station, made from expandable units and extendable panels

I bow down before you, sir.   

But my interest is in rotating research stations that can be built near-term. I just can't believe it's that difficult. And we only have two data points for the biological effects of gravity equal to or less than 1g: 1g and 0g. A simple station as I described would pretty much, uh, revolutionize our knowledge on this topic, which is absolutely critical for human expansion into the Solar System.

Note that many values of g are possible with such a station because 1) each hab has multiple levels, and 2) angular velocity can be changed at will using thrusters.

[Oersted]

How do you dock with it?

Two hab modules, a docking hub, and a truss would make a "minimal" rotating facility with two levels of g, given an offset center of gravity. In my pic, the blue hab is for Lunar G, and the red hab is Mars g. (No, the distances aren't accurate, and I didn't include solar arrays, radiators and whatnot, but that's what you get for five minutes of work.)

Here is an interesting link: http://www.quantumworks.com/jbis_article.htm

Punder, that graphic in your posting also suggests a new kind of docking, the "screw it in" method!  :-)

[punder]

How do you dock with it?

Two hab modules, a docking hub, and a truss would make a "minimal" rotating facility with two levels of g, given an offset center of gravity. In my pic, the blue hab is for Lunar G, and the red hab is Mars g. (No, the distances aren't accurate, and I didn't include solar arrays, radiators and whatnot, but that's what you get for five minutes of work.)

Here is an interesting link: http://www.quantumworks.com/jbis_article.htm

Punder, that graphic in your posting also suggests a new kind of docking, the "screw it in" method!  :-)

Ha, hey I'm just channeling Stanley Kubrick.      Just match the roll rate, no problemo.

[Oli]

The hab in the Martian looked pretty good to me. Low g and large windows for a great view. I guess the interior could be a bit more comfy.

[Steve D]

We are talking a lot about what will fit in the BFR. What about how we will be getting these things out the door? We have a 9 meter diameter space but will the door allow a 9 meter object to pass through it?

[Barrie]

I recall some long ago "research".   Maybe SBIR/STTR or the like that explored a steered and propelled device that extruded molten or glassy or plastic material on a structural flight path to provide girders or surfaces for a space structure.   Always liked the concept.

First example had some material like thermite melting aluminum or iron and extruding it in a stream while steering the extruding device in space.

Like large-scale 3D printing using a free-flying print-head?

[speedevil]

We are talking a lot about what will fit in the BFR. What about how we will be getting these things out the door? We have a 9 meter diameter space but will the door allow a 9 meter object to pass through it?

The BFS has a cargo hatch that appears to be capable of passing a ~9m*3.6*3.6m object (or a hair more in width and height), and you can in principle stack several such items on a rail system for deployment out of the hatch. (if you remove the cabins, or as I have hypothesised, they're on rails for easy removal)

The BFC is less well defined, and has never had what seems like more than a notional sketch.
Similarly, the final version of the tanker, other than it will look 'silly'.

As one point, if the cabins of BFS are in fact demountable cargo containers, they fit easily through the hatch, and can have mating connectors on the faces, the problem almost resolves to one of Lego.
They are perhaps smaller than one would like, but ready modularity may trump that, especially as they would in principle be easily manufacturable by any manufacturer globally, and shipped readily in standard transport.

[watermod]

I recall some long ago "research".   Maybe SBIR/STTR or the like that explored a steered and propelled device that extruded molten or glassy or plastic material on a structural flight path to provide girders or surfaces for a space structure.   Always liked the concept.

First example had some material like thermite melting aluminum or iron and extruding it in a stream while steering the extruding device in space.

Like large-scale 3D printing using a free-flying print-head?

Yes!

[oldAtlas_Eguy]

I recall some long ago "research".   Maybe SBIR/STTR or the like that explored a steered and propelled device that extruded molten or glassy or plastic material on a structural flight path to provide girders or surfaces for a space structure.   Always liked the concept.

First example had some material like thermite melting aluminum or iron and extruding it in a stream while steering the extruding device in space.

Like large-scale 3D printing using a free-flying print-head?

Yes!

A device that can print aluminum can print a seamless torus with any openings with flanges and mounting point all integrated to the primary torus structure. Only needs the blanks/ingots to feed the 3D printer. The printer has its own power solar array as part of the device plus arms that can stabilize the device while printing to the item that is being printed. Grab points are printed as the printer prints the torus. No limitations on size. Just takes longer a linear calculation based on thickness and area of wall.

This is the end direction current research is going. All other in space assembly is at best a temporary measure or a supporting capability to have multiple 3D printers printing many parts simultaneously with the assembly of the parts printed. Increases the construction completion time from start to finish. A BTW decking is printed as well so no need to install any structural elements inside the torus. Floors, walls, stairs, mounts, cabinets, etc are all printed simultaneous to the printing of the shell.

Assumption of a project:
1 - First launch is the 3D printer. This device is not a mass constraint but a volume constraint due to its solar arrays, thermal radiators, arms, on-board spare parts (such as print heads and even arms), propulsion system, and the 3D printer.

2 - Next are the launches of the aluminum blanks. These launches occur as often as the 3D printer can use up the blanks.

3 - Next is the launch of the internal and external parts/equipment installation robots. External assembly robots have solar arrays and propulsion.

4 - Next is the non-printable internal and external parts. Priority is to power generation, thermal control systems, and the distribution of power, cooling. Next is instruments and computer/controls and comm distributions (Ethernet or Ethernet like systems). Next is other habitation items. Water, farming, ECLSS, furniture, displays(Monitors) and human interfaces.

5 - Human habitation supplies.  After sufficient pressurants the the torus is pressurized then the torus systems is fueled for initial spin-up. Torus is now available for habitation with the arrival of pressurized supplies.


Costs are somewhat linear but actually get a little cheaper per unit volume as total volume increases.

[Barrie]

Any sense in having a coarse, high deposition rate print-head for structure, and smaller high-res print-heads that add precision details such as mounting lugs for attached equipment?

[oldAtlas_Eguy]

Any sense in having a coarse, high deposition rate print-head for structure, and smaller high-res print-heads that add precision details such as mounting lugs for attached equipment?

If it is the exact same materiel then there is no reason not to. The course system deposits most of the materiel while the fine system adds smooth surfaces and other fine feature items.

These systems would be operating 24/7 continuously as long as there is a supply of blanks. A robot that transports stores blanks and can shift them over to a printer may be another robot needed to speed up construction. It would accept a specialized container of the blanks such that it would hold 2 of them so that when a BFR delivers a new container of blanks the empty one is offloaded to the BFR for return to Earth.

Eventually the Blanks will stop coming from Earth but arrive from a IRU plant receiving raw material from either the Moon or an asteroid. at which point the BFR does not slow down in flights but switches to the deliver of the everything else: robots, accouterments, supplies, and humans.

[KelvinZero]

Shorter term, for minimum assembly:

What about a telescoping nested set of cylinders? The thing expands to a long truncated cone instead of a long cylinder, but so what? This would fit arbitrarily well inside the Cargo BFS bay, because the inner cylinders could be longer than the outer ones.

Each truncated cone could be engineered with a slight curve so that a handful of them could fit together to form a torus. The tube radius would have bulges approaching 9m but go down to say 3m. Straight versions of the truncated cones could be used to reach the hub where docking takes place.