Author Topic: Zero gravity and Deep Space Habitat  (Read 29802 times)

Offline A_M_Swallow

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Re: Zero gravity and Deep Space Habitat
« Reply #100 on: 12/06/2018 08:07 pm »
5 pages of people trying to re-invent the wheel.  As many in the past have pointed out - rotate a pressurized habitat linked to an empty upper stage via a few hundred feet of tethering.  Quite large radii of rotation are possible with tethers.

Yes I agree. For those who want to have a backup habitat module in case there is a problem, just have two side by side with an airlock between them on the same side of the spin arm and extend the cable with the counter weight a little further out and/or adjust the centre of spin on the cable.

For concerns about people, liquids and things moving about and disturbing the rotational balance, I would have thought that many such movements would cancel themselves out eventually and that the residual imbalances could be dealt with by an automated system monitoring the rotational forces in 3 dimensions and adjusting counter weights inside or outside of the craft and or increasing / decreasing the rate of spin.


If you are using tethers the length of the tether can also be adjusted.

Offline DaveJes1979

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Re: Zero gravity and Deep Space Habitat
« Reply #101 on: 12/10/2018 05:48 pm »
Yes I agree. For those who want to have a backup habitat module in case there is a problem, just have two side by side with an airlock between them on the same side of the spin arm and extend the cable with the counter weight a little further out and/or adjust the centre of spin on the cable.

The Dragon or Starliner capsule that brought you to the habitat is the backup.  Just like with ISS, you get into it and return to earth in the event of an emergency.  There will have to be a specialized docking adapter and structural provisions to connect the capsule to the habitat.

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For concerns about people, liquids and things moving about and disturbing the rotational balance, I would have thought that many such movements would cancel themselves out eventually and that the residual imbalances could be dealt with by an automated system monitoring the rotational forces in 3 dimensions and adjusting counter weights inside or outside of the craft and or increasing / decreasing the rate of spin.

You already have to have an RCS to spin up the stack in the first place.  No need to add more mass and complexity.

Online Slarty1080

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Re: Zero gravity and Deep Space Habitat
« Reply #102 on: 12/10/2018 11:02 pm »
Yes I agree. For those who want to have a backup habitat module in case there is a problem, just have two side by side with an airlock between them on the same side of the spin arm and extend the cable with the counter weight a little further out and/or adjust the centre of spin on the cable.

The Dragon or Starliner capsule that brought you to the habitat is the backup.  Just like with ISS, you get into it and return to earth in the event of an emergency.  There will have to be a specialized docking adapter and structural provisions to connect the capsule to the habitat.

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For concerns about people, liquids and things moving about and disturbing the rotational balance, I would have thought that many such movements would cancel themselves out eventually and that the residual imbalances could be dealt with by an automated system monitoring the rotational forces in 3 dimensions and adjusting counter weights inside or outside of the craft and or increasing / decreasing the rate of spin.

You already have to have an RCS to spin up the stack in the first place.  No need to add more mass and complexity.
Sure. But the point I was making was that a spinning platform need not be destabilised if people and things move about inside it.
The first words spoken on Mars: "Humans have been wondering if there was any life on the planet Mars for many decades well ... there is now!"

Offline Paul451

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Re: Zero gravity and Deep Space Habitat
« Reply #103 on: 12/11/2018 07:40 am »
5 pages of people trying to re-invent the wheel.  As many in the past have pointed out - rotate a pressurized habitat linked to an empty upper stage via a few hundred feet of tethering.  Quite large radii of rotation are possible with tethers.

But why is that necessary for such a small habitat, with a trained crew?

People can apparently adapt to ridiculously high spin rates, and the length of a reasonable 3-person habitat plus a docking/power/etc adaptor plus an empty upper-stage is sufficient for modest spin rates at modest gravities.

Offline DaveJes1979

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Re: Zero gravity and Deep Space Habitat
« Reply #104 on: 12/12/2018 07:18 pm »
But why is that necessary for such a small habitat, with a trained crew?

Tethers are light. Why push the limits of human tolerance for coriolis when the whole point is to create an environment that is conducive to human health and comfort?  Also, who says you will have a trained crew (rather than untrained passengers on the way to Mars)?

Human body tolerance is not the only issue.  All systems with fluids will have issues.  And people will want to cook and serve food and take showers.

Offline Paul451

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Re: Zero gravity and Deep Space Habitat
« Reply #105 on: 12/13/2018 08:07 am »
But why is that necessary for such a small habitat, with a trained crew?
Tethers are light.

But unstable and historically error-prone. (The best "tether" option seems to be to combine it with a pressurised tube to put the tethers/cables under tension, tethers to put the pressure-tube under compression. Increases the vibrational and twisting stability over either alone.)

Also, who says you will have a trained crew (rather than untrained passengers on the way to Mars)?

The topic of the thread, DSH.

Offline DaveJes1979

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Re: Zero gravity and Deep Space Habitat
« Reply #106 on: 12/17/2018 04:09 am »
But unstable and historically error-prone.

Tethers that are designed to be structural-only have historically worked just fine.  And a spinning stack is inherently stable.

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(The best "tether" option seems to be to combine it with a pressurised tube to put the tethers/cables under tension, tethers to put the pressure-tube under compression. Increases the vibrational and twisting stability over either alone.)

This makes no sense from any angle.  Vibration is a non-issue, and if you are worried about the tether twisting you put the tether mount on a bearing.

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The topic of the thread, DSH.

The point of a deep space habitat for conducting human partial gravity research is that it isn't an end in itself.  The point is to determine if and how humans can endure long-duration missions to various destinations in our solar system.  Since this is under the Mars sub-topic, we are specifically concerned with both trips to Mars and extended stays on the surface.

Re: Zero gravity and Deep Space Habitat
« Reply #107 on: 03/11/2019 07:55 am »
aside from on board life support system, gravity attenuation increase the change of health risk for long duration space flight. another factor to consider how retrofitting electrically induced artificial gravity (AG) on crew module may pose serious health issue aside from mechanical issue

« Last Edit: 03/11/2019 07:57 am by 3amg0 »

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