Author Topic: rotating space station as a astronaut rehabilitation-center  (Read 4354 times)

Offline Hotblack Desiato

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Currently, the astronauts from ISS and later from interplanetary missions directly plunge from zero-g to 1g (with a brief period of multiple gs during descent). And then they have to recover in our 1g environment, which is quite difficult.

Since a lot of plans involve the Exploration Gateway at EML1 or 2 for departure and return (return from Mars, dock with with EG, and enter an Orion Spacecraft), how about setting a rotating spacestation up, where long-term zero-g astronauts can recover by incrementially raising the gravity.

A typical mission profile would be: Astronauts who spent a longer time in zero-g step onto the 0.1g level, start training, then the go to the next level, and so on, until they reach the 1g-level. My hope is, that such an incremental way allows them to recover faster than directly going to 1g, as it is done now.

The station itself could be quite simple in the beginning, but advance further and further.

A central node for docking and zero-g environment (but spinning), and two theters radially extending. One of them just has a counter weight on the end (maybe a tank or something like this), and ion engines. The other theter is long (at least 500m) and has a habitat module at its end, and ion engines too. The astronauts enter that module, and the station slowly starts spinning. A cable climber can move cargo and crew from the node to the hab module at the end.

The downside would be, that this configuration would just allow one level of gravity at the same time. And it needs fuel.

Later, when the station needs more capabilites, they can add more hab modules, at least 10m apart from each other (in the outer region, they require much more). The connections between the habitats could be some BEAM-like tube (a flexibly expandable structure, connecting 2 distant modules) with a ladder, cables, ropes and pipes inside (maybe even an elevator cabin). This structure would allow docking at the node, and then gradually step down into the gravity well, until 1g is reached. The structure would just stop or slow down for maintenance (EVA in the 1g-area, and something happens to the astronauts theter... that would result in an astronaut leaving the station quite rapidly).

Maybe, they could use a similar station in orbit around Mars for training before they go down to the surface. Or in orbit around asteroids, just to have an environment with some sort of gravity (doesn't need to be a full g).

ideas, suggestions?

Offline KristianAndresen

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Well, if you put your rotating station in a cycler orbit, then you don't have the problem in the first place of people getting weak from interplanetary travel in zero g.

Offline redliox

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Well, if you put your rotating station in a cycler orbit, then you don't have the problem in the first place of people getting weak from interplanetary travel in zero g.

Small problem people who advocate cyclers totally miss: interplanetary orbits are inconvenient and rendezvousing in them is a risky idea, as in if you 'miss' your small transfer spacecraft becomes your only spacecraft for the remainder of trip. 

A rehabilitation center should be convenient, so it probably would be located closer to Earth so the astronauts can regain any lost strength before touching the ground.

We still need to see how well a rotating space station can be arranged, and if you're worried about preventing the problem to begin with refer to Rober Zubrin's idea of using a spent stage on a tether to counterweight a rotating ship.
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Offline KristianAndresen

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Small problem people who advocate cyclers totally miss: interplanetary orbits are inconvenient and rendezvousing in them is a risky idea, as in if you 'miss' your small transfer spacecraft becomes your only spacecraft for the remainder of trip. 

Or, perhaps they just assume the reliability of a rendezvous will increase in the future. Doesn't seem terribly unreasonable, considering we've landed a rocket on propulsion now.

Offline The Amazing Catstronaut

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Small problem people who advocate cyclers totally miss: interplanetary orbits are inconvenient and rendezvousing in them is a risky idea, as in if you 'miss' your small transfer spacecraft becomes your only spacecraft for the remainder of trip. 

Or, perhaps they just assume the reliability of a rendezvous will increase in the future. Doesn't seem terribly unreasonable, considering we've landed a rocket on propulsion now.

It's not an avionics problem, it's a hardware responsiveness and reliability problem. Everything needs to throttle exactly when you need it.
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Offline Alf Fass

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Small problem people who advocate cyclers totally miss: interplanetary orbits are inconvenient and rendezvousing in them is a risky idea, as in if you 'miss' your small transfer spacecraft becomes your only spacecraft for the remainder of trip. 

Or, perhaps they just assume the reliability of a rendezvous will increase in the future. Doesn't seem terribly unreasonable, considering we've landed a rocket on propulsion now.

It's not an avionics problem, it's a hardware responsiveness and reliability problem. Everything needs to throttle exactly when you need it.

In transport bits of vehicles are always having to work when they're needed, sometimes (relatively rarely) they don't and people are injured or die, the solution would have been to never have invented horse drawn carriages.
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Offline Alf Fass

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Currently, the astronauts from ISS and later from interplanetary missions directly plunge from zero-g to 1g (with a brief period of multiple gs during descent). And then they have to recover in our 1g environment, which is quite difficult.

Since a lot of plans involve the Exploration Gateway at EML1 or 2 for departure and return (return from Mars, dock with with EG, and enter an Orion Spacecraft), how about setting a rotating spacestation up, where long-term zero-g astronauts can recover by incrementially raising the gravity.

A typical mission profile would be: Astronauts who spent a longer time in zero-g step onto the 0.1g level, start training, then the go to the next level, and so on, until they reach the 1g-level. My hope is, that such an incremental way allows them to recover faster than directly going to 1g, as it is done now.

The station itself could be quite simple in the beginning, but advance further and further.

A central node for docking and zero-g environment (but spinning), and two theters radially extending. One of them just has a counter weight on the end (maybe a tank or something like this), and ion engines. The other theter is long (at least 500m) and has a habitat module at its end, and ion engines too. The astronauts enter that module, and the station slowly starts spinning. A cable climber can move cargo and crew from the node to the hab module at the end.

The downside would be, that this configuration would just allow one level of gravity at the same time. And it needs fuel.

Later, when the station needs more capabilites, they can add more hab modules, at least 10m apart from each other (in the outer region, they require much more). The connections between the habitats could be some BEAM-like tube (a flexibly expandable structure, connecting 2 distant modules) with a ladder, cables, ropes and pipes inside (maybe even an elevator cabin). This structure would allow docking at the node, and then gradually step down into the gravity well, until 1g is reached. The structure would just stop or slow down for maintenance (EVA in the 1g-area, and something happens to the astronauts theter... that would result in an astronaut leaving the station quite rapidly).

Maybe, they could use a similar station in orbit around Mars for training before they go down to the surface. Or in orbit around asteroids, just to have an environment with some sort of gravity (doesn't need to be a full g).

ideas, suggestions?

Rather than a separate facility I think it more likely to just have part or all of a manned station spinning. As for Mars, I think the cost of more fuel to have shorter transit times is likely to soon win out over having people and hardware tied up in long transit times.

Table 1 here gives required delta v vs transit times to Mars.
http://www.gdnordley.com/_files/Going_to_Mars.html
« Last Edit: 06/05/2016 10:13 pm by Alf Fass »
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Offline KelvinZero

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I quite like the idea of a rehabilitation station. It depends on what future space industry evolves so it is very speculative at the moment. It could avoid the huge cost and danger of shuttling workers to and from earth every 6 months or so. Instead they visit this thing.

Offline Paul451

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Can't see that a spin station would offer anything more than slow recovery on Earth. We use head-down bed-rest (HDBR) to simulate the damage caused by micro-g. So if you want to ease the recovery for astros, you would simply use periods of head-up inclined bed-rest to reduce the effects of 1g.

(But realistically, treatment would just be the same as physio for a patient recovering from a long period of inactivity.)

But regardless of whether it's useful: if you have a spin-station, why are you spending a year or more in micro-g?

[Aside: I'd like to see some experimentation with >1g as a prophylactic treatment for micro-g damage. If astros spend a few weeks training in a large centrifuge on Earth, does that slow/prevent/delay the damage caused by micro-g? Likewise, once the astros are back on Earth, and reasonably back to health, could time spent at >1g help repair some of the long-term damage that remains?]
« Last Edit: 06/06/2016 02:20 pm by Paul451 »

Offline Paul451

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Small problem people who advocate cyclers totally miss: interplanetary orbits are inconvenient and rendezvousing in them is a risky idea, as in if you 'miss' your small transfer spacecraft becomes your only spacecraft for the remainder of trip.

How the frak do you "miss"? What scenario would put you on trajectory to Mars, but not allow rendezvous with a cycler on the same trajectory?

If you miss the cycler trajectory, then by definition you are not heading to Mars. You're heading randomly into deep space. You're dead. No different than if you launched on an all-in-one Mars mission that suffered a similar failure.

refer to Rober Zubrin's idea of using a spent stage on a tether to counterweight a rotating ship.

A tether is probably overkill. Simply the length of a spent stage would be enough to allow a reasonable g-load.

The problem is we have no data on the health effects of partial gravity, and wildly contradictory data on adaptation to spin.

Offline mikelepage

Small problem people who advocate cyclers totally miss: interplanetary orbits are inconvenient and rendezvousing in them is a risky idea, as in if you 'miss' your small transfer spacecraft becomes your only spacecraft for the remainder of trip.

How the frak do you "miss"? What scenario would put you on trajectory to Mars, but not allow rendezvous with a cycler on the same trajectory?

If you miss the cycler trajectory, then by definition you are not heading to Mars. You're heading randomly into deep space. You're dead. No different than if you launched on an all-in-one Mars mission that suffered a similar failure.

Uh... unless I'm misremembering, it's not the same trajectory.  Depending on which cycler architecture you're using, the cycler itself does not match velocities with Earth and/or Mars, and certainly not both, therefore the transfer craft trajectory surface to cycler !=! Earth-Mars transfer trajectory.  Having said that, the consequences of "missing" is exactly why Aldrin and others developed the "semi-cycler" architectures.

Btw, Would be interested in your input on this thread Paul:
https://forum.nasaspaceflight.com/index.php?topic=40485.0

Offline Paul451

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Re: rotating space station as a astronaut rehabilitation-center
« Reply #11 on: 06/09/2016 03:20 pm »
Uh... unless I'm misremembering, it's not the same trajectory.  Depending on which cycler architecture you're using, the cycler itself does not match velocities with Earth and/or Mars,

My point is that if you 'miss' the cycler, you aren't on an MTI, you're on a random trajectory and hence you're dead. Same as you would be if you were doing an all-in-one mission and your MTI burn failed part way. Using a cycler doesn't change that.

Likewsie a semi-cycler. It doesn't really change the risk. You've simply shifted the risk from the crew-shuttle to the cycler's main MTI burn. If it achieves escape, but not MTI, then you're dead. The only advantage is that if the main propulsion is SEP, you might have a chance to repair the thrusters via EVAs, and have enough fuel and life-support to figure out a trajectory that gets you back to Earth. If you're lucky.

Aside: The semi-cycler reduces the delta-v requirement for the crew-shuttle, but increases it for the cycler itself. That may be manageable if the cycler uses SEP. It also increases the flight-time, but it increases the number of synods you can use the cycler. (Aldrin had proposed a pair of cyclers, one optimised for each leg. Some schemes would require up to six cyclers to cover every launch/return window. The semi-cycler means you only need one ship but can still use it upto every synod.)

Offline whitelancer64

Currently, the astronauts from ISS and later from interplanetary missions directly plunge from zero-g to 1g (with a brief period of multiple gs during descent). And then they have to recover in our 1g environment, which is quite difficult.

<snip>

ideas, suggestions?

This is a massive, expensive solution to a minor problem... astronauts are almost always up and walking normally within hours of landing back on Earth.

As Paul451 notes, the easier solution is head-up inclined resting, which is already done immediately after capsule egress (as famously seen after Soyuz landings) and this can easily be continued after leaving the landing site.  Further physical therapy to restore muscle strength is typically completed within a month or two.
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Offline Coastal Ron

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Re: rotating space station as a astronaut rehabilitation-center
« Reply #13 on: 06/09/2016 03:41 pm »
Currently, the astronauts from ISS and later from interplanetary missions directly plunge from zero-g to 1g (with a brief period of multiple gs during descent). And then they have to recover in our 1g environment, which is quite difficult.

Since a lot of plans involve the Exploration Gateway at EML1 or 2 for departure and return (return from Mars, dock with with EG, and enter an Orion Spacecraft), how about setting a rotating spacestation up, where long-term zero-g astronauts can recover by incrementially raising the gravity.

I've taken to calling artificial gravity stations beyond LEO a "refuge", since I see them as a place that inhabitants on Mars would be able to visit to enjoy a higher gravity (i.e. birth-normal) environment.  No doubt that would also be rehabilitation, just that I think of it as a refuge.

And if you have the ability to retain some of your 1G physical attributes while at Mars, then that lessens the need for a rehab facility in space near Earth.  Or at least shortens the amount of rehab time.

Quote
The station itself could be quite simple in the beginning, but advance further and further.

This arena needs more work, and certainly we need small test systems to validate that artificial gravity does have positive results, and to figure out how little gravity can be tolerated.

Once we've determined that, then the design for the real rotating space station is likely to be completely different from the test versions.  I've been doing some work on a design, and tethered masses don't really scale up.  But full scale stations are going to require a LOT of mass, even for 1st generation ones, so we're going to have to have a well defined need before committing to building them.

My $0.02
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Offline Robotbeat

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Offline A_M_Swallow

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Re: rotating space station as a astronaut rehabilitation-center
« Reply #15 on: 06/09/2016 08:33 pm »

I've taken to calling artificial gravity stations beyond LEO a "refuge", since I see them as a place that inhabitants on Mars would be able to visit to enjoy a higher gravity (i.e. birth-normal) environment.  No doubt that would also be rehabilitation, just that I think of it as a refuge.

And if you have the ability to retain some of your 1G physical attributes while at Mars, then that lessens the need for a rehab facility in space near Earth.  Or at least shortens the amount of rehab time.
{snip}

It is easy to build a 1G centrifuge on the Moon and Mars. The cabin can be a rover with the wheels taken off. The counterweight can be local stone. Add electric motor at the centre and metal beams to support the weight. Refuel life support when stationary.

Offline Paul451

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Re: rotating space station as a astronaut rehabilitation-center
« Reply #16 on: 06/10/2016 07:06 am »
The cabin can be a rover with the wheels taken off. The counterweight can be local stone. Add electric motor at the centre and metal beams to support the weight.

Why take the wheels off? Banked track. No hub, no counterweight. 6RPM/1g is only 80kmh/50mph.

Too easy.


Offline RonM

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Re: rotating space station as a astronaut rehabilitation-center
« Reply #17 on: 06/10/2016 01:47 pm »
Yeah, right. That looks like a great work environment.  ::)

Offline A_M_Swallow

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Re: rotating space station as a astronaut rehabilitation-center
« Reply #18 on: 06/11/2016 02:58 am »
The cabin can be a rover with the wheels taken off. The counterweight can be local stone. Add electric motor at the centre and metal beams to support the weight.

Why take the wheels off? Banked track. No hub, no counterweight. 6RPM/1g is only 80kmh/50mph.

Too easy.

{snip}

If you use a rail design the power can be transferred through the rails. Underground electric trains are very reliable.

The cabin would have to connect to the chassis at the right angle to make the floor 'flat', but that is an easy calculation.

p.s. The banked track can be built out of ISRU sintered material. A very large potential saving in launch costs.
« Last Edit: 06/11/2016 03:02 am by A_M_Swallow »

Offline Paul451

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