Commercial Space Station Design

[HebaruSan]

What a fun topic!

Hosting paying civilians is a big change from employees that go through a highly selective recruitment process and extensive training.

Health:

• You'll need at least one member of staff dedicated to medical plus equipment; check-ups, emergencies, etc.
• You'll want to be able to send a return vessel on short notice for some of those emergencies
• Microgravity muscle degradation might leave a mere mortal severely impaired, not clear this is a risk worth taking

Safety:

• Passengers will have higher rates of forgetting to secure objects, spilling liquids, etc.
• How hard is it to move fast enough under your own power in microgravity to injure yourself?

Comfort:

• Even the best of the best with "the right stuff" still sometimes puke in microgravity. "Just deal with it" is a less adequate response if the person vomiting is paying a hefty sum to be there and missing out on the experience while they recover.
• Space toilets and showers

A ring/disc station solves so many of those issues. New arrivals could be moved to the spin gravity sections to acclimate, then climb ladders "up" to the microgravity rooms when/if they feel ready (and climb back down if they feel sick). Floating debris would be a non-issue outside the microgravity rooms, which could have staff members stationed to monitor. I'd love to see a regular white porcelain toilet in space! A ring would be more expensive than making an ISS clone with established tech, but we'll have to figure it out eventually, so why not claim some of the patents for your own company?

Regarding orbital parameters, I don't see universal launch access as a big plus; contracting with SpaceX for everything would be simpler and more consistent (fewer schedules to coordinate, fewer contacts to notify with new docking procedures, etc.), so any Florida-accessible inclination will do. Most visitors are probably primarily interested in viewing their own places of origin, which a moderate inclination offers more frequently than polar. I'd want low, consistent re-entry speeds (and burns), so a low circular orbit wins on that front.

So: A rotating ring in a low circular Florida-inclination orbit. I don't have any special thoughts on power or heat.

[sevenperforce]

The whole quarantine process for the ISS is something I hadn't thought about until I saw it discussed in the Dragon 2 launch webcast. There's no room for pathogens on the ISS and so the crew have to be completed segregated with everyone they contact being health-screened and wearing masks. Imagine if someone ended up with the flu....

[kerbiloid]

2 hours ago, sevenperforce said:

With respect to inclination...higher is better for universal access.

For some tasks you need polar orbits, for some of them- equatorial ones.
As unlikely a huge station would be used as a simple photosat like KH-10/11, its low inclination looks being more required.
So, unlikely even a small station should have >50°.

2 hours ago, sevenperforce said:

Nonzero orbital eccentricity could be very interesting if the argument of periapsis was equal to the inclination. Then, your farthest distance from Earth takes you (nearly) over the south pole and you zip at high speed over the north pole.

Twice per turn - throgh the radiation belts, and with aerobatics just for the approaching, leave alone the docking.

2 hours ago, sevenperforce said:

If the station is constructed as a torus with an open hallway running all the way around the circumference, then fans could be designed to push air around the hallway to induce a very, very slight breeze

Or keep whirling in the hallway, while the torus is full of CO2.

Also any centrifuge should stay balanced with no breaks.
A bunch of cylinders can be balanced. What about the torus?

***

Another business plan:
Artificial gravity + no extradition.
Low taxes, no financial monitoring. So, it should be proclaimed independent.

Edited March 11, 2019 by kerbiloid

[DDE]

11 hours ago, Lisias said:

This changes your line of arguing somehow?

Extremely. You rolled out the usual line of argument that you can build a highway to nowhere, and then suddenly traffic will show up - a line I’ve seen repeated by countless space advocates.

Bottom line is, the various “killer apps” for manned commercial space presense just keep flopping - whether space tourism or, as it was in the 90s, zero-G pharmaceuticals. Now, you could argue that it’s due to prhibitive freight costs - but it could also be because of fundamental problems.

It may just be that no-one in the actual industry would want such a station.

10 hours ago, HebaruSan said:

So: A rotating ring in a low circular Florida-inclination orbit. I don't have any special thoughts on power or heat.

Then probably a fixed solar array on one side, windows on the other.

[kerbiloid]

Probably, we should first analyze simplified cases:
1. Say, we can put everything into LEO for free, and have the artificial gravity there. What can we use this for?
2. What kind of business do we have on ground which lacks LEO+AG?

(Moon and beyond are unavailable.)

Edited March 12, 2019 by kerbiloid

[DDE]

21 minutes ago, kerbiloid said:

Probably, we should first analyze simplified cases:
1. Say, we can put everything into LEO for free, and have the artificial gravity there. What can we use this for?
2. What kind of business do we have on ground which lacks LEO+AG?

(Moon and beyond are unavailable.)

Tourism, certain types of microgravity experiments/manufacturing that are often still marginally available on Earth or can be substituted, real-time unjammable visual intelligence... and given that we’re cheating, space marines with drop pods.

The fact that it’s free and privately-owned entirely eliminates the basic prestige factor.

Oh, wait, it’s with a-grav. Scratch item 2. So we only have (relatively) pure vacuum.

[kerbiloid]

2 minutes ago, DDE said:

certain types of microgravity experiments/manufacturing that are often still marginally available on Earth or can be substituted,

I mean, mass business, not tiny one.

Marines and spies are not .com, they're .gov., so also no.

Edited March 12, 2019 by kerbiloid

[YNM]

19 hours ago, StrandedonEarth said:

film studios, for unmatched realism (the novelty factor alone will sell tickets for the first few movies). 

Not sustainable. CGI will soon cross all uncanny valleys and be indistinguishable.

[Green Baron]

It is already now, or at least very close, even in real time:

http://www.realtimerendering.com/

 

Edited March 12, 2019 by Green Baron

[sevenperforce]

5 hours ago, DDE said:

You rolled out the usual line of argument that you can build a highway to nowhere, and then suddenly traffic will show up - a line I’ve seen repeated by countless space advocates.

Bottom line is, the various “killer apps” for manned commercial space presense just keep flopping - whether space tourism or, as it was in the 90s, zero-G pharmaceuticals. Now, you could argue that it’s due to prhibitive freight costs - but it could also be because of fundamental problems.

Exactly where I didn't want this thread to go. There's fierce disagreement on whether a business case for LEO tourism (or LEO human presence at all) closes, and we've spun round and round in numerous threads. Let's avoid repeating those arguments.

For the purposes of this thread, let us suppose that there is a solid business case for placing a space station in orbit and visiting it regularly. As with any business case, money is not unlimited. We can assume that the station will have some sort of tourism value, though that may or may not be its primary business case. Those are the parameters.

/endrant

[Kerwood Floyd]

27 minutes ago, sevenperforce said:

For the purposes of this thread, let us suppose that there is a solid business case for placing a space station in orbit and visiting it regularly.

But I think we need to know what the business case is before we can design the station.

[Green Baron]

Well, you said "commercial" ;-) Commerce needs, imo, an economical basis.

I must object the money argument: since ~10 to 15 years money is not a limiting factor any more. The markets are flooded with too much of it, seeking valves like harbours without traffic, unfinished airports, useless borrows under major cities, half baked infrastructure for energy, Hotels without guests, you name it :-)

Ability and will to realize and finish limits big projects, not lack of money. But that touches forbidden ground i fear.

But ok, waving it all away and looking at the technological and organizational aspects. But aren't we then back to all those more or less reasonable design studies, proposals, artist's impressions of wheels, balls, tubes, lattices, panels, etc. pp. ? Everyone can choose her favourite design from one of many, we can speculate over health, provisioning, safety, collision risk, transport media to and from, which will sooner or later lead us to space elevators and dyson spheres.

Isn't there a vacuum without a specific reason ? Wouldn't it be more interesting to have a "commercial" aspect on which to build ?

Edit ninja'd :-)

Edited March 12, 2019 by Green Baron

[Ultimate Steve]

4 minutes ago, Kerwood Floyd said:

But I think we need to know what the business case is before we can design the station.

We should probably stick with two business cases that have been proven to exist, at least to a certain extent. Tourism, and research (selling capacity to NASA or similar).

[magnemoe]

18 minutes ago, Ultimate Steve said:

We should probably stick with two business cases that have been proven to exist, at least to a certain extent. Tourism, and research (selling capacity to NASA or similar).

Add other actors, it an nice place to test equipment for use in space if you want it back for study. This get more relevant as access to LEO get cheaper. 
 

[sevenperforce]

Here's a question that moves away from debates over business case.

With present tech, is it feasible at all to construct pressure vessels in space, or do all modules need to be lofted intact? For example, it would obviously be very nice (whether we are looking at a tourism case, a crew sanity case, or pretty much any other application) to have at least one very large atrium, probably at or near the center of the station. This would be limited to a diameter of 4.6 meters if launched on a SpaceX or ULA rocket and 6.2 meters if launched on New Glenn. 4.6 meters is not too shabby--larger than the Kibo module on the ISS--but still rather constricting.

If it were possible to construct pressure vessels in space, this could be greatly enhanced. Note that an expandable module a la Bigelow is not ideal due to the lack of windows. You'd probably want to go with a fold-open design, but you'd still need some way to actually seal the seams.

[kerbiloid]

Spoiler

1 hour ago, Green Baron said:

Hotels without guests, you name it :-)

Certainly, "Cortez"!
Just finished watching season 5.
.

 

1 hour ago, Green Baron said:

Isn't there a vacuum without a specific reason ? Wouldn't it be more interesting to have a "commercial" aspect on which to build ?

Internal energy of the 2-atomic ideal gas E/m = 5/2 * R * Temperature / MolarMass ~=  200 kJ/kg ~= 600+ m/s of kinetic energy.

So, the artificial vacuum on ground is still many times cheaper than the natural one in space.

28 minutes ago, sevenperforce said:

have at least one very large atrium, probably at or near the center of the station.

If it's rotating, they will be hitting the opposite wall at double speed.

P.S.
If there were some kind of business requiring the space, and if it was neither immoral, nor illegal, probably NASA would have already tried it after Saturn/Apollo, when NASA funds had been cut, and they were feverishly seeking the next theme to develop, choosing between the orbital station and shuttle.

Edited March 12, 2019 by kerbiloid

[Racescort666]

30 minutes ago, sevenperforce said:

you'd still need some way to actually seal the seams

Welding seems like an obvious solution. The station doesn't need to be immediately habitable or at least there could be a build up over time. Also, there's a chance that adhesive seals could be used but that would be new technology that would have to be developed.

Something that no one has mentioned yet with regard to rotating stations is CG management. 

[Green Baron]

Sorry, i meant an argumentative vacuum, not a physical, like we can start an argumentation anywhere without a real goal, leading to the usual speculations.

Yeah, an atrium is an earthly concept, an open central part of a building, derived from the "usual" Roman constructions. It is difficult to imagine a meeting place or so in weightlessness or low gravity without imagining bruises.

Glueing may be better than welding for the really tight connections. "Can we weld it or must we glue it ?" where there is mechanical stress and for composite materials. Or shall we build in stainless steel, the fashion material of the season :-) ?

Edit: scrub stainless steel, too loud for living space as it expands and contracts from changes in sunshine, day&night, etc.

Edited March 12, 2019 by Green Baron

[sevenperforce]

Just now, Green Baron said:

Yeah, an atrium is an earthly concept, an open central part of a building, derived from the "usual" Roman constructions. It is difficult to imagine a meeting place or so in weightlessness or low gravity without imagining bruises.

Glueing may be better than welding for the really tight connections. "Can we weld it or must we glue it ?" where there is mechanical stress and for composite materials. Or shall we build in stainless steel, the material of the season :-) ?

An interesting possibility would be a "steel zipper" approach, where the unfolding panels join interlocking teeth. The teeth could be painted with some sort of thermal bonding agent...perhaps an inhibited thermite analogue.

Internal seal would tend to be the challenging point.

[kerbiloid]

A large inner voulme should anyway be splitted into smaller ones.
(See "damage control plan")

So, you need only attachable small ones and unsealed envelope around them.

[DDE]

On 3/11/2019 at 6:21 PM, StrandedonEarth said:

film studios, for unmatched realism (the novelty factor alone will sell tickets for the first few movies). 

Zero-G is so 1938. Wires can do a lot.

Also, do not underestimate just how unrealistic reality can be.

1 hour ago, kerbiloid said:

P.S.
If there were some kind of business requiring the space, and if it was neither immoral, nor illegal, probably NASA would have already tried it after Saturn/Apollo, when NASA funds had been cut, and they were feverishly seeking the next theme to develop, choosing between the orbital station and shuttle.

NASA did... without stating a single detail, but I’m sure space industry in general was mentioned alongside orbital solar power.

[Ultimate Steve]

Okay. So, I think we know our constraints better.

• No Starship, only current Launch Vehicles
• Must have a purpose, can be tourism, science, other applications, all of them, or some of them.

A thing to think about:

• If Starship, another cheap SHLV, or maybe even New Glenn reach operational status before our station can make a profit, it probably won't.

And from that, in sequence:

• Our station shouldn't be too ambitious if it needs to stick with current technology, or else it will get stuck and become an irrelevant money sink.
• Our station should aim to become operational soon so we have time to make profit.
• Our station should use proven tech, and should be small-ish so it can be built in time.

I mean, obviously, it's never* getting built, but with the lessons learned from that station we could then build something more ambitious in the potential Starship era.

If we're sticking mostly with proven tech, orbital construction is out, at least to a certain extent. Artificial gravity is probably out as well.

[sevenperforce]

13 minutes ago, Ultimate Steve said:

...from that, in sequence:

• Our station shouldn't be too ambitious if it needs to stick with current technology, or else it will get stuck and become an irrelevant money sink.
• Our station should aim to become operational soon so we have time to make profit.
• Our station should use proven tech, and should be small-ish so it can be built in time.

I mean, obviously, it's never* getting built, but with the lessons learned from that station we could then build something more ambitious in the potential Starship era.

If we're sticking mostly with proven tech, orbital construction is out, at least to a certain extent. Artificial gravity is probably out as well.

We could suppose that Starship is delayed. New Glenn could represent the upper limit of what we are allowed in terms of putting something monolithic in LEO.

Full artificial gravity may be out, but "minigravity" may be feasible. Build it in a design which works well under tension, then put a very very slight rotation on it...low enough that the core of the station won't make you dizzy and gives you the full microgravity experience, but significant enough that you (and objects around you) tend to settle to the floor if you are bunked at the outer cabins. 

Canadarm construction and inflatable habs are both proven tech. Orbital assembly of the actual pressure vessels is definitely unproven tech but if someone was able to manage it, more power to them. 

 

Edited March 12, 2019 by sevenperforce

[magnemoe]

5 minutes ago, Ultimate Steve said:

Okay. So, I think we know our constraints better.

• No Starship, only current Launch Vehicles
• Must have a purpose, can be tourism, science, other applications, all of them, or some of them.

A thing to think about:

• If Starship, another cheap SHLV, or maybe even New Glenn reach operational status before our station can make a profit, it probably won't.

And from that, in sequence:

• Our station shouldn't be too ambitious if it needs to stick with current technology, or else it will get stuck and become an irrelevant money sink.
• Our station should aim to become operational soon so we have time to make profit.
• Our station should use proven tech, and should be small-ish so it can be built in time.

I mean, obviously, it's never* getting built, but with the lessons learned from that station we could then build something more ambitious in the potential Starship era.

If we're sticking mostly with proven tech, orbital construction is out, at least to a certain extent. Artificial gravity is probably out as well.

Why would starship or new Glen kill the station, yes you could run something like the shuttle's spacelab in an manned starship but it would not replace an station for long term research. 

I agree you either build something modest or you wait for starship / new Glen and scale things up quite a bit. 
Saw the gateway station idea, it did not have zero g areas who make it pretty pointless. you want an pretty large 0 g area for research and docking, put tanks just outside as it make it easier to use, then low g, this is probably more fun than 0 g and make construction and other stuff easier, then the high g areas for other work like the kitchen, offices and gym perhaps sleeping but the low g zone might be more pleasant. 

 

[sevenperforce]

1 hour ago, Racescort666 said:

Something that no one has mentioned yet with regard to rotating stations is CG management. 

If it's rotating slowly enough then CG management is less of a problem.