Artificial gravity station?

Terraformer · 2015-04-20 14:36:55

GW Johnson has mentioned this a few times. But how would it be built?

I'm thinking of one constructed of multiple Bigelow modules, with a central module (which has the docking ports on) and a couple of modules attached to it via trusses. There would be a tunnel (with a ladder) connecting the central module to them. The entire thing would be 20m from the centre to the outer modules, rotating at 4 RPM; this would give rise to roughly Martian equivalent acceleration in the outer modules. Though I don't know what it would be like in the centre (well, quite odd I suppose, there would still be significant acceleration)...

Such a station could be expanded, perhaps creating a hexagon with six habitats surrounding a central one. Useful, perhaps, as somewhere for astronauts to recuperate for a day out of every week.

kbd512 · 2015-04-20 18:32:05

There are three basic configurations that use existing technology:

1. Connect a module to a counterweight using a tether and spin the module using thrusters (a baton would work the same way, but the tether would be replaced with more modules); if the baton is attached to something, you can use an electric motors for rotation.

2. Rotate a torus using motors if it's attached to something at the center or thrusters if it's not attached to anything at the center

3. Rotate a rotor using the same methods used to rotate a torus

Just like the Schwartz, each method has its upsides and downsides.

tahanson43206 · 2022-01-25 08:15:52

This topic by Terraformer has one post, by kbd512...

It's time for a refresh, and the pdf from which this snippet was taken is available for reading online, thanks to discovery by SpaceNut in the Practical Ship topic.

3.3 Orbital control system
The station will have an attitude and orbit control
system (AOCS) to maintain a stable orientation and
orbit, as full control is needed over the six rotational and
translational degrees of freedom. Starport 1’s unique
challenge compared to other space stations is that it is a
spinning station and therefore a gyroscope. Future
research will need to account for mitigating these effects
and stabilising the station orbit. Starport 1’s orientation
must be such that the rotating ring is in the orbital plane,
with the minimum cross-section being exposed to
reduce drag. This orientation reduces the need for
stationkeeping.

The pdf is dated 2016, and it is about the Axiom space station concept.

I note that the problem of achieving stability of the rotating vessel, and performing orbital maneuvers, was left for a future time.

That future time is ** now **, because both RobertDyck and kbd512 are hard at work on competing designs for a passenger ship capable of the trade route between Earth and Mars.

It has been proposed that a scale model of a rotating passenger space craft design be launched and tested in space, at a cost of (about) $2,000,000 (US). This sum is quite reasonable for organizations the scale of Mars Society or the (much) larger National Space Society.

The point I would like to make is that the scale model needs to be constructed so that the force structure is also built to scale.

For a 5,000 ton vessel (as suggested by GW Johnson) the forces at play will be measured in tons, and the structural elements required to achieve the required strength will be strong in tension or compression or twisting moment, depending upon the application.

The scale model needs to be designed to accurately and faithfully re-create the frailty of force components compared to the loads.

A cable that runs from the prow of the central shaft to carry loads from the rotating habitat may be represented by a cotton thread in the model, or by a very thin filament of material that won't stretch the way cotton would stretch.

(th)

Mars_B4_Moon · 2023-09-13 10:30:32

This is a thread dedicated to spinning space stations, it could be worth bumping

We had Salyuts, Skylab, MIR and now the ISS

We still have no artificial gravity station, I suggested putting mouse or fish or maybe rats or some plant and animal, maybe insect or lizard a 'guinea pig' on a spinning station either around Mars, Venus, the Moon or even a Bio-Sat around Earth to test artificial gravity.

China Tiangong Space Station, smaller than the ISS

Tianzhou-5 has reentered over southern Pacific

https://twitter.com/CNSpaceflight/statu … 9587884370

NASA astronaut accidentally breaks record after being stranded in space

https://www.chron.com/news/space/articl … 361644.php

In pop culture the Movies and Videogames, some asthetics are very Fanasty like StarWars, Star Trek many fantastical elements and realism can be and still a feature in pop culture, movies and in video games

How Accurate is Starfield's Space Travel? We Asked an Expert
https://www.ign.com/articles/how-accura … -an-expert
“It looks here like they really put some thought into this thing operating in a non artificial gravity environment as well,”

Last edited by Mars_B4_Moon (2023-09-13 10:53:22)

tahanson43206 · 2023-09-13 10:49:47

Thanks to Mars_B4_Moon for returning this topic to view.

RobertDyck is hard at work, preparing to give another talk about Large Ship at the upcoming Mars Society Convention.

If there is a forum reader who is interested in the concept that RobertDyck is developing, we have an entire topic dedicated to "Large scale Colonization Ship"

https://newmars.com/forums/viewtopic.php?id=9124

(th)

GW Johnson · 2023-09-13 16:07:15

The equation you want for spin gravity is number of Earth gees = [(R, m)/(55.891 m)]*[(n, rpm)/(4 rpm)]^2. If you are less picky about significant figures, you can use 56 m for the reference R. The 55.891 m figure is to the nearest mm, and that is quite good enough accuracy, thank you very much.

We also have rather credible suggestive evidence that humans cannot tolerate high spin rates long term, but that something near 4 rpm maximum actually is tolerable long term. Higher spin rates on a shorter radius are the first thing people want to try, bit what little evidence we have suggests that approach is tolerable only over shorter time intervals, and even then only by people extensively trained and acclimatized to it. So 3 or 4 rpm is "it".

There are two axes about which an object can spin stably, out of the 3 axes available to a nonsymmetrical object. These are the axes with the maximum and minimum values for mass moment of inertia. The intermediate value will not spin stably.

An object with some symmetry of one kind or another has only two distinct values of mass moment of inertia. There are two axes with the same value. Either value will spin stably.

A uniform sphere has only one value for moment of inertia about all 3 axes. You can essentially spin that stably about any axis you want to use. But only if uniformly spherical.

As to the gees you want in a station or a spaceship, consider this: we evolved at 1 gee. All our experiences for 6+ decades with 0 gee says extended exposure is bad. We have absolutely zero experience with extended exposure at fractional gee! Simple prudence says you start out designing for 1 gee artificial gravity for long duration exposures. No ifs, ands, or buts.

If you do baton-type spin, or build a spinning disk with multiple radial levels inside, you can make the outer level 1 gee. The levels at lesser radius will be fractional gee, with which you can easily experiment long-term in Earth orbit. Does that tell you what sort of Earth orbiting stations we should be building? And what we should have been building all these decades?

Once we have a definitive answer as to what level of fractional gee might really be therapeutic, we can design to that level. But bear in mind, people migrating from a lower-gee place like Mars or the moon, back to Earth, will need to strengthen themselves for some extended interval in a 1-gee environment, before they can actually return to Earth's surface. Especially since re-entry gees can vary from 4 to 15, depending upon entry interface speed at Earth. If you are used to fractional gee, those levels are far more daunting than they are for someone adapted to 1 gee.

Just food for thought.

GW

Last edited by GW Johnson (2023-09-13 16:16:09)

Mars_B4_Moon · 2023-09-26 05:54:40

Turning up gravity for space fungi study
https://www.spacedaily.com/reports/Turn … y_999.html
Fungi in space have been a plot point in Star Trek: Discovery, but they are also a very real problem for astronauts and space stations. United Nations co-sponsored testing by a team from Macau in China subjected fungi to hypergravity with ESA's fast-spinning centrifuge.

A claim by the Chinese, 6 months

China capable of protecting astronauts from effects of space weightlessness
https://www.spacedaily.com/reports/Chin … s_999.html
China has the capability to protect astronauts from the effects of a weightless environment for 180 days in space, according to a forum on aerospace medicine that kicked off Thursday in Beijing.

Last edited by Mars_B4_Moon (2023-09-26 05:58:49)

Mars_B4_Moon · 2024-05-15 12:57:19

Blue Origin sets the date for its first crewed suborbital space trip in 21 months
https://www.geekwire.com/2024/blue-orig … pace-trip/

Bezos may also be interested in an artificial gravity station, they commented on designs by using centrifugal force we can generate something equivalent to gravity on Earth

There was also this 2021 NASA news item on Moon Gravity

'NASA, Blue Origin Partner to Bring Lunar Gravity Conditions Closer to Earth'
https://www.nasa.gov/centers-and-facili … -to-earth/

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#1 2015-04-20 14:36:55

Artificial gravity station?

#2 2015-04-20 18:32:05

Re: Artificial gravity station?

#3 2022-01-25 08:15:52

Re: Artificial gravity station?

#4 2023-09-13 10:30:32

Re: Artificial gravity station?

#5 2023-09-13 10:49:47

Re: Artificial gravity station?

#6 2023-09-13 16:07:15

Re: Artificial gravity station?

#7 2023-09-26 05:54:40

Re: Artificial gravity station?

#8 2024-05-15 12:57:19

Re: Artificial gravity station?

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