Realistic, near-term, rotating Space Station

[LMT]

OK.  Now that it has got a bit quieter around here, can we get back to the topic at hand ?

But first, maybe the station-seal posters could set up a poll on all their notions.  For a community checkpoint.

[Asteroza]

Ho ho

New NPR article about retiring ISS. https://www.npr.org/2024/02/21/1232639289/international-space-station-retirement-space-stations-future

Interesting part is at the end

>Gatens says one piece of technology that is being developed at Blue Origin is a big rotating space station that, when finished, would have artificial gravity.

This is coming from Robyn Gatens, director of the ISS, so seems like a reliable source. This is the first confirmation I've seen of Blue Origin developing artificial gravity.

[Coastal Ron]

Ho ho

New NPR article about retiring ISS. https://www.npr.org/2024/02/21/1232639289/international-space-station-retirement-space-stations-future

Interesting part is at the end

>Gatens says one piece of technology that is being developed at Blue Origin is a big rotating space station that, when finished, would have artificial gravity.

This is coming from Robyn Gatens, director of the ISS, so seems like a reliable source. This is the first confirmation I've seen of Blue Origin developing artificial gravity.

Yeah, saw you also posted on the Artificial Gravity Testbeds thread, and this is certainly good news!

We'll need to wait for more info, but I would be surprised if they build a wheel-type design, and I'm hoping they go beyond the "spinning stick" style that VAST is planning to build.

Also, I'm not thinking this will be a permanent station, but more of a testbed. But again, we need more info to inform our wild guesses... 

[MickQ]

Back in reply #4425 I proposed an adaptation/ modification to a rotating docking system put forward by lamontagne in the previous few posts.  Any thoughts on that ??

[LMT]

Back in reply #4425 I proposed an adaptation/ modification to a rotating docking system put forward by lamontagne in the previous few posts.  Any thoughts on that ??

This shouldn't be a historical thread.  With modern GNC software, rotating ports are an outdated mechanical complication.  Ships can dock autonomously, even with tumbling targets; e.g., Oestreich 2021, Silvestrini and Lavagna 2022, Huang et al. 2022.  Thread posters should be aware.

[lamontagne]

Back in reply #4425 I proposed an adaptation/ modification to a rotating docking system put forward by lamontagne in the previous few posts.  Any thoughts on that ??

https://forum.nasaspaceflight.com/index.php?topic=34036.4425

For this to work wouldn't the port on the ship have to be at the center of gravity of the ship?  Otherwise it would induce some significant strain as it was accelerated up to rotation speed?

If the port is at the center of gravity, then the ship can be rotated and matched up beforehand, as in 2001 A Space Odyssey?  And then indeed, as gracefully sugested by LMT, the rotating port would not be required.

I think a rotating port is best used if you have a relatively small station and you don't want to leave a ship attached for a long time, and the visiting ship is assymetrical.  Quite a few conditions.  Like the joined image.

[lamontagne]

My small drum station, don't remember if I posted it here.

[MickQ]

My suggestion was to transfer the mass of the docking ship/s into the plane of rotation of the ring station design of the previous post. Would not work with this latest one.

[MickQ]

In my view, your Small Drum Station screams out for a docking collar on each end of the central core.  The ship noses in, is grabbed and clamped in position and an access tube extends, locks on and is pressurised.

I would love to see the 2001 dance occur for real.

[Coastal Ron]

Back in reply #4425 I proposed an adaptation/ modification to a rotating docking system put forward by lamontagne in the previous few posts.  Any thoughts on that ??

I'm not sure I understood your proposal from #4425, but that may be a problem on my part (visuals help  ).

I think there are two different approaches that seem workable without mandating that the visiting vehicle be designed to rotate. Some people are OK with mandating visiting vehicles rotate, which is fine, but not what I focus on. So the approaches I'm considering are:

1. For stations small enough that they don't have some sort of large docking area, a "floating gangplank" can be used that has rotating collars on the station side and on the visiting vehicle side. This is the proposal that Lamontagne and I proposed a while back (sorry, don't have the post # right now), and does not requires the visiting vehicle to rotate. It does require a section where cargo and people "spin up" to match the rotation of the station.

2. For stations that are large enough, the station captures the non-rotating visiting vehicle and then "spins up" the vehicle so that it can be attached to the station.

For the rotating space station designs I've been working on, I assume a non-rotating support station is located nearby, and that is where the warehouse is located, and visiting vehicles can dock there also. Everything coming over to the station would be on purpose built short distance "shuttles" that just large cylinders, and they would be grabbed by the station like #2 above. But otherwise the station itself would need to be able to handle large visiting vehicles. And yes, it is an extra step, but it reduces complexity on the station side, which for me is deemed important. YMMV... 

[LMT]

...approaches that seem workable without mandating that the visiting vehicle be designed to rotate.

Which real spacecraft aren't "designed to rotate"?   

[lamontagne]

...approaches that seem workable without mandating that the visiting vehicle be designed to rotate.

Which real spacecraft aren't "designed to rotate"?   

The Space shuttle (retired).
Starship, except for the special case of the Moon landing version.

[LMT]

...approaches that seem workable without mandating that the visiting vehicle be designed to rotate.

Which real spacecraft aren't "designed to rotate"?   

The Space shuttle (retired).
Starship, except for the special case of the Moon landing version.

Can't rotate?

[MickQ]

Back in reply #4425 I proposed an adaptation/ modification to a rotating docking system put forward by lamontagne in the previous few posts.  Any thoughts on that ??

I'm not sure I understood your proposal from #4425, but that may be a problem on my part (visuals help  ).

If you look at post #4424, the simple ring station design, the ship is docked to one of two rotating docking ports ( post #4423 ) on that orange central tube section.  I proposed putting an extra rotating joint on each end of that orange tube so that after a ship is docked and secured then that tube rotates 90 degrees bringing the ship/s inside the ring therefore putting the mass of any docked vessels in the plane of rotation, not hanging off the side.  My thought being that it would be more stable.

Just an idea.   Sorry I don’t have the skills for illustrations.

[Paul451]

...approaches that seem workable without mandating that the visiting vehicle be designed to rotate.

Which real spacecraft aren't "designed to rotate"?   

The Space shuttle (retired).
Starship, except for the special case of the Moon landing version.

Can't rotate?

Wilfully misunderstanding other posters so you can pretend they said something stupid is not useful. Meaning was obvious from context. Delete pointless posts.

[Paul451]

[post #4424] [post #4423] [post #4425]
I proposed putting an extra rotating joint on each end of that orange tube so that after a ship is docked and secured then that tube rotates 90 degrees bringing the ship/s inside the ring therefore putting the mass of any docked vessels in the plane of rotation, not hanging off the side.  My thought being that it would be more stable.

A ring has a lot of mass in the plane of rotation, one or two Starships hanging off the front/back won't cause instability.

Whereas rotating the docking section so the Starship(s) are in the plane of rotation means: a) they are "hanging" (even though the g-load is small, it's still a whole extra thing the docking port has to deal with); b) they can't undock in an emergency (which is the whole point in having at least one ship docked at all times to a small station); c) they can't undock at all unless the whole system works (to which you've added a fairly major point-of-failure) which could screw with landing schedules; d) because the ships are "hanging", you have to "lift" a hundred tonnes or so through that rotation, even if the g-load is (random number) 1/20th of 1g, that's still 5+ tonnes torquing the rotation; and e) it doesn't solve the lengthwise asymmetry of vehicles like Starship, which might prevent them from being able to rotate when docked as depicted in #4424.

Unless I've missed something major, I don't see any point. It seems like an idea done for the sake of doing the idea.

[LMT]

If the port is at the center of gravity, then the ship can be rotated and matched up beforehand, as in 2001 A Space Odyssey?  And then indeed, as gracefully sugested by LMT, the rotating port would not be required.

CoG ports aren't required, no; GNC software deals with CoG via thrust, as part of a versatile tumble-dock maneuver calc.  And solving tumble-dock makes the follow-on undocking calc simpler, yes? 

Do look at those papers.

they can't undock in an emergency

Of course they can.  You might discuss the GNC software with Lamontagne, instead of ignoring it.

The large-angle maneuver control technology of spacecraft attitude has a wide range of applications in space missions, such as rendezvous and docking, on-orbit assembly, orbiting, and formation flying. It is one of the critical factors for completing various tasks. In recent years, finite-time control methods have been widely used to improve the accuracy and speed of spacecraft attitude control [1,2]. Compared with the cooperative situation, the rendezvous and proximity of non-cooperative targets have broader application prospects in space monitoring and service, deep space exploration, etc. However, it also presents more significant challenges due to the lack of information communication. Therefore, to meet the non-cooperative requirements of space missions, autonomous control modes that can identify non-cooperative target pose information and achieve attitude tracking are proposed [3,4].

[Twark_Main]

A ring has a lot of mass in the plane of rotation, [it] won't cause instability.

That's why I always pour a lead keel around all my ring stations. 

I'm oddly reminded of the days when Detroit couldn't make lightweight cars. Instead, they rebranded unnecessary mass as "road-hugging weight." 

Anyway, just observing that a 3-barbell layout will have plenty of "axis-hugging weight" too. You don't strictly need a ring layout just for this purpose — it is sufficient, but it's not really necessary. This isn't to contradict anything Paul said btw, just preemptive.


As for emergency escape while hanging, I always assumed you'd do it like Voyager Station and their ring of DreamChasers (or if you prefer a sci-fi touchstone, the Starfury drop from B5).

[MickQ]

[post #4424] [post #4423] [post #4425]
I proposed putting an extra rotating joint on each end of that orange tube so that after a ship is docked and secured then that tube rotates 90 degrees bringing the ship/s inside the ring therefore putting the mass of any docked vessels in the plane of rotation, not hanging off the side.  My thought being that it would be more stable.

A ring has a lot of mass in the plane of rotation, one or two Starships hanging off the front/back won't cause instability.

Whereas rotating the docking section so the Starship(s) are in the plane of rotation means: a) they are "hanging" (even though the g-load is small, it's still a whole extra thing the docking port has to deal with); b) they can't undock in an emergency (which is the whole point in having at least one ship docked at all times to a small station); c) they can't undock at all unless the whole system works (to which you've added a fairly major point-of-failure) which could screw with landing schedules; d) because the ships are "hanging", you have to "lift" a hundred tonnes or so through that rotation, even if the g-load is (random number) 1/20th of 1g, that's still 5+ tonnes torquing the rotation; and e) it doesn't solve the lengthwise asymmetry of vehicles like Starship, which might prevent them from being able to rotate when docked as depicted in #4424.

Unless I've missed something major, I don't see any point. It seems like an idea done for the sake of doing the idea.

Ok.  Like I said, just an idea.

[mikelepage]

As for emergency escape while hanging, I always assumed you'd do it like Voyager Station and their ring of DreamChasers (or if you prefer a sci-fi touchstone, the Starfury drop from B5).

Bit of a tangent, but this has come up before. Is it just me, or does anyone else think it's overkill to have multiple *atmospheric entry vehicles* on standby in case of evacuation?

Even in the case of an explosive decompression event, you'd only need airtight pods with transponders that people can jump into quickly, and a ship that can go around picking them up in the aftermath. I'd always imagined - maybe I've read this somewhere - you wouldn't even need to have escape pods with all the system overheads that requires. Instead you'd have "emergency" cabinets situated at intervals around the station - much like fire-extinguishers are placed in large buildings.

In each cabinet I'd imagine you'd have 1) a fire extinguisher, 2) some kind of plate + putty kit for sealing MMOD impact holes in a hurry and 3) some kind of single-use, flat-pack inflatable "body pod". Hit one button and this one-size-fits-all starts blowing up similar to an inflatable mattress, with the same gas being breathable. Cellphone-like interface controls the transponder. Single circular "hatch" is a clear hemisphere for your head, that you can jump into and shut from the inside. Added functionality could include small "booties" or gloves that your hands/feet could go into for some tactile feedback and mobility, or even some token OMS to allow the user to arrest any tumble and/or maneuver stay relatively near to the remains of the station, but none of that is super necessary to its life-saving purpose (keeping the user alive for a few more hours).