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#1 2013-12-26 11:21:42

Quaoar
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Registered: 2013-12-13
Posts: 665

Surface centrifugue for a Mars colony

There are a lot of topics about artificial gravity douring space flight, but we are not sure that Martian 0.37 gee is enough to avoid muscular hipotrophy.
Probably 2-3 hour day of walking in a heavy spacesuit, puls weighted clothes, squat training and aerobic exercise and an appropriate diet may be enough to mantein the muscular strenght and the bone mineralization of an adult astronaut for the 500 days of a mission.
But if we look foreward, to a permanent settle, what will happen to a Mars borne child?
Are 0.37 gee, plus gym and weighted clothes enought to develop normal muscolar and bone, that allow him to return to Earth in a future?
Having no reliable data, I think may be better to built a centrifugue facility, where the coloniest can train 2-3 hour day in a high gravity environment.

Last edited by Quaoar (2013-12-26 11:22:04)

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#2 2013-12-26 15:37:54

Spaniard
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From: Spain
Registered: 2008-04-18
Posts: 133

Re: Surface centrifugue for a Mars colony

A rotation structures is completely viable.

http://www.artificial-gravity.com/sw/SpinCalc/

Radius = 207
Rotation = 2 rotations/minute
Speed (tangential) = 156 km/h (a moderate train achieve this)
Gravity (horizontal) = 0,93

(0,93^2+0,376^2)^(1/2)=1,03 g

An structure like that could be rotate using magnetic levitation, using superconductors or permanent magnets like on Inductrack using little energy to compensate air friction and other energy dissipation.

On the sides, the horizontal component of the "gravity" is greater, so people and things would be on almost horizontal. A curved stair could connect with the center. At first, "up" (from inside perspective) is going to the center (from outside perspective). When you goes up from inside, the position of the floor gets more and more parallel to the floor of Mars, and the stairs twist and turns into a ramp and later a corridor to the center.
Another configuration could include a "elevator" from the center to the edges. First, moves to the edges like a car, but tilt at the same time to be parallel to the sum of gravity and centrifugal apparent force, so , from the perspective of the passenger it goes forward at first, and later, goes "down", and when it reach the "bottom" (the side of the rotating structure) reach a 1g "gravity" (the sum of real gravity and centrifugal force by rotation).

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#3 2013-12-26 16:38:15

louis
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From: UK
Registered: 2008-03-24
Posts: 7,208

Re: Surface centrifugue for a Mars colony

I think in terms of raising children on Mars there is a bigger problem. I believe it is the case that studies in zero G have shown abnormal development in embryos. Accordingly, we will need  1G facilities either on the surface, or in Mars orbit, where a woman can gestate the embryo safely. There may be a trend towards artificial insemination with a view to gestating twins.

I have never considered 1G facilities on the surface a practical solution but am happy to be persuaded otherwise.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#4 2013-12-26 17:11:39

Quaoar
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Posts: 665

Re: Surface centrifugue for a Mars colony

louis wrote:

I think in terms of raising children on Mars there is a bigger problem. I believe it is the case that studies in zero G have shown abnormal development in embryos. Accordingly, we will need  1G facilities either on the surface, or in Mars orbit, where a woman can gestate the embryo safely. There may be a trend towards artificial insemination with a view to gestating twins.

I have never considered 1G facilities on the surface a practical solution but am happy to be persuaded otherwise.

Homebox genes seems have difficoult in microgravity to recogize where is the right place to make the head and to make the feet. 0.37 gee may be enough to give such orientation, but we have no data. Before procreate, it will be better to test if animal embrion can develop correctly. If not, pregnat woman will live in a one gee centrifuge.

Last edited by Quaoar (2013-12-26 17:12:50)

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#5 2013-12-26 20:31:21

JoshNH4H
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From: Pullman, WA
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Re: Surface centrifugue for a Mars colony

I am also very interested in the effects of .37 g.  The issue with saying anything at this point is that we don't know.  We know what happens to humans when they're subjected to 0 g for long periods of time: The primary health issue related to this is bone loss.  And then we know what happens at 1 g, which is to say that bone mass is relatively steady as a function of time. 

However, there are some promising results in this domain, even in 0 g.  Because these symptoms are quite similar to the symptoms of osteoporosis, it was found on the ISS that Osteoporosis medicine significantly decreases the rate of bone loss in microgravity.  It was shown that the efficacy of these drugs decreased with time.

What really pops out to me is that bone mass is a "use it or lose it" deal.  The reason why it goes away in space is that the microgravity environment requires much less bone mass than does Earth.  The body naturally responds by making less bone.  We can artificially increase the rate of bone production or decrease the rate of bone elimination (both of which are natural processes that happen all the time in our bodies here) but in time the body will increase its efforts to equilibrate with its surroundings, and bone loss will eventually ensue. 

Given that we use .38 g (Mars' gravity is closer to .38 than .37) I would expect bone loss to ensue 62% as quickly as it did in microgravity, give or take (That is to say, 1-.38 times as quickly).  This would make a 900 day round trip Mars mission equivalent to a 550 day stay in LEO-- still unacceptable.  However, with the additional provision of osteoporosis medication, and still including exercise (Given that there will be some gravity in the hab, by putting handles on e.g. containers of water the astronauts can actually lift weights and perhaps even do things like MMA fights) I would expect things to be fine.

All of this goes out the window if you don't care about a return to Earth.  Because the decreasing bone density is an adaptation to lower levels of gravitation, there is not necessarily any issue with this in the context of a permanent trip to Mars.  I would expect bone density to be much lower for people and animals raised on Mars (and experiments on animals during missions can certainly test this), but I wouldn't expect this to be a problem so long as they remained on worlds with no more than 1.5 to 2 times as much gravity as Mars (5.6-7.4 m/s^2; There are very few places in the solar system with this level of gravity.  So far as I know, the next-lowest surface gravity in the Solar System after Mars is Venus, with 8.9 m/s^2).

People on Mars are likely to be tall and lanky, with less muscle than Terrans.  For someone born on Mars, it would take the equivalent of a bodybuilder to be able to go to Earth.  I would imagine that more arduous for a Martian than the trip would be the months of exercise and special drugs that would be needed to go to Earth.


-Josh

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#6 2013-12-26 20:52:35

louis
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From: UK
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Re: Surface centrifugue for a Mars colony

This is an interesting issue. Perhaps at some future date Mars historians will look wryly on such speculation! smile

For me I think the following tentative conclusions are relevant:

1. Procreation will require some extended replication of 1G

2. Bone mass can be increased on Mars through wearing of weighted clothing.

3. Problems with immune system alleged to relate to zero G may have more to do with simply being absent from a "threat" environment. Returnees from Mars may have to be gradually subjected to various viruses and bacteria on Earth, to reboot their immune system.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#7 2013-12-26 22:20:10

SpaceNut
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Posts: 29,428

Re: Surface centrifugue for a Mars colony

The popular carnival ride the Gravitron is what comes to mind rotating 28 rpm with a diameter approximate 60 feet.


http://en.wikipedia.org/wiki/Centripetal_force

http://en.wikipedia.org/wiki/Centrifugal_force

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#8 2013-12-27 08:41:26

Quaoar
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Posts: 665

Re: Surface centrifugue for a Mars colony

JoshNH4H wrote:

I am also very interested in the effects of .37 g.  The issue with saying anything at this point is that we don't know.  We know what happens to humans when they're subjected to 0 g for long periods of time: The primary health issue related to this is bone loss.  And then we know what happens at 1 g, which is to say that bone mass is relatively steady as a function of time. 

However, there are some promising results in this domain, even in 0 g.  Because these symptoms are quite similar to the symptoms of osteoporosis, it was found on the ISS that Osteoporosis medicine significantly decreases the rate of bone loss in microgravity.  It was shown that the efficacy of these drugs decreased with time.

The study you quote was performed with Alendronate: it may give a good medium mineralization, but the bones may become brittle: bone strenght depend not only on mineralization, but also on the correct orientation on bone trabeculae in counteracting weight, that is difficoult to obtain in microgravity. Bone is continously created by osteoclasts and destroyed by osteoblast, in the way to achieve a perfect orientation of trabeculae, giving the maximal strenght with the minimal mass. Alendronate blocks osteoblast activity shifting the balance on the side of osteosinthetys, but in long terms, the not perfect orientament of trabeculae may result in thigh bone spontaneos fracture. This "frozen bone" effect may happen in Earth gravity environment: we have no data on microgravity, but probably it may be worst.

We also know hormons like myostatin, wich rises in microgravity environment, resulting in muscular mass loss: on STS 188 mission a new myostatin inhibitor was tested on mice, with very good preliminary data http://www.dsls.usra.edu/meetings/hrp2012/pdf/4203.pdf

In a future, I belive it will be possible to solve via pharmacology all space releted problems, like microgravity and cosmic ray protection. But at the moment our knowledge of human physiology is too much incomplete to relay only on drugs for long term space exploration missions. The best we can do now is to recreate as much is possible an Earth like environment, using artificial gravity.

JoshNH4H wrote:

What really pops out to me is that bone mass is a "use it or lose it" deal.  The reason why it goes away in space is that the microgravity environment requires much less bone mass than does Earth.  The body naturally responds by making less bone.  We can artificially increase the rate of bone production or decrease the rate of bone elimination (both of which are natural processes that happen all the time in our bodies here) but in time the body will increase its efforts to equilibrate with its surroundings, and bone loss will eventually ensue. 

Given that we use .38 g (Mars' gravity is closer to .38 than .37) I would expect bone loss to ensue 62% as quickly as it did in microgravity, give or take (That is to say, 1-.38 times as quickly).  This would make a 900 day round trip Mars mission equivalent to a 550 day stay in LEO-- still unacceptable.  However, with the additional provision of osteoporosis medication, and still including exercise (Given that there will be some gravity in the hab, by putting handles on e.g. containers of water the astronauts can actually lift weights and perhaps even do things like MMA fights) I would expect things to be fine.

Probably, Mars gravity, plus weighted clotes, 2-4 h/day of walk in spacesuit, plus squat, aerobic exercise may result in good muscolar and bone manteinment.

JoshNH4H wrote:

and perhaps even do things like MMA fights

I'm very courious about martial arts in microgravity and low gravity: if you are interested we can open a new topic about it.


JoshNH4H wrote:

All of this goes out the window if you don't care about a return to Earth.  Because the decreasing bone density is an adaptation to lower levels of gravitation, there is not necessarily any issue with this in the context of a permanent trip to Mars.  I would expect bone density to be much lower for people and animals raised on Mars (and experiments on animals during missions can certainly test this), but I wouldn't expect this to be a problem so long as they remained on worlds with no more than 1.5 to 2 times as much gravity as Mars (5.6-7.4 m/s^2; There are very few places in the solar system with this level of gravity.  So far as I know, the next-lowest surface gravity in the Solar System after Mars is Venus, with 8.9 m/s^2).

People on Mars are likely to be tall and lanky, with less muscle than Terrans.  For someone born on Mars, it would take the equivalent of a bodybuilder to be able to go to Earth.  I would imagine that more arduous for a Martian than the trip would be the months of exercise and special drugs that would be needed to go to Earth.

If I will be a Mars settler I will not like my personal life choise must be a point of not return even for my children. I will like to have healty children with a corrected developed body, able to visit Earth if they like and free to return living on it if they want. So, why not built in the colony a one gee facility?

Last edited by Quaoar (2013-12-27 08:47:41)

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#9 2013-12-27 10:52:25

SpaceNut
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Re: Surface centrifugue for a Mars colony

100 meter at 3rpm wil get you near the 1g level but what I am concerned about is the fact that we can barely land a 10 meter diameter space craft. That said where are the materials coming from to build something so large and massive. The power drain to move a large mass will be hard to generate. The motor or motors to make it move.

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#10 2013-12-27 10:57:53

Decimator
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Posts: 39

Re: Surface centrifugue for a Mars colony

louis wrote:

1. Procreation will require some extended replication of 1G

What do you base this on?  We have no data between zero and one gee.

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#11 2013-12-27 12:17:45

Quaoar
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Registered: 2013-12-13
Posts: 665

Re: Surface centrifugue for a Mars colony

SpaceNut wrote:

100 meter at 3rpm wil get you near the 1g level but what I am concerned about is the fact that we can barely land a 10 meter diameter space craft. That said where are the materials coming from to build something so large and massive. The power drain to move a large mass will be hard to generate. The motor or motors to make it move.

In the first times, when there will 1-3 habitat and 4-6 crew member, who stay only 500 days, I think the best they can do is to avoid procreation, so they probably dont need a centrifugue.
The surface centrifugue will be built only in a second time when the colony is able to use in situ matherials and the first settlers will start to procreate.

Last edited by Quaoar (2013-12-27 14:02:28)

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#12 2013-12-27 12:22:56

Quaoar
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Registered: 2013-12-13
Posts: 665

Re: Surface centrifugue for a Mars colony

Decimator wrote:
louis wrote:

1. Procreation will require some extended replication of 1G

What do you base this on?  We have no data between zero and one gee.

Probably 0.38 gee is enough for a correct embryo-fetal development, but as you correctly say, we have no data (if not, it would pose a serious limit on animal breeding)
A one gee facility will be very likely needed for a correct body development of the martian children.

Last edited by Quaoar (2013-12-27 12:24:38)

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#13 2013-12-27 16:35:01

GW Johnson
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From: McGregor, Texas USA
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Posts: 5,784
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Re: Surface centrifugue for a Mars colony

What not having any experience between 0 gee and 1 gee really means,  is that for any mission too long to endure 0 gee safely,  then your artificial spin gravity design must be 1 full gee,  no fractional values.  Period.  Not until we have the experience to know whether 0.38 gee or 0.16 gee (or whatever) is enough or not. 

Spin gravity designs must get this 1 full gee at a tolerable spin rate.  That's a fuzzy limit,  but untrained civilians seem to be able to tolerate 3,  perhaps 4,  rpm quite handily for extended periods.  If you design for 1 gee at 4 rpm,  you need a 56 m radius from the center of gravity to your 1 gee deck location.   We know enough from the bed rest studies to understand that the sleeping quarters can be fractional gee,  it's your day shift work station that needs to be the 1 full gee. 

The time you can endure 0 gee is also a fuzzy limit,  very fuzzy indeed.  It depends upon how much health damage you can tolerate.  There is bone density loss,  heart and circulatory system damage,  and very good reasons to suspect both immune system and vision damage.  No telling what else.  For a 3-4 gee ride home from LEO,  6 months to about a year,  perhaps a little more,  seem to be tolerable. 

For the 9-15 gee free return from Mars,  the astronauts would have to be in a whole lot better physical condition than is typical from 6 months on ISS.  Yet,  we are talking about a nominal 2.5 year mission to Mars.  That's 6 to 8.5 months one-way.  I think everybody knows that doing this in free fall is a bad idea,  probably fatal,  but there are still a lot of folks who just won't face that fact yet.  Including some at NASA,  disappointingly enough.

This issue points out very clearly what a stupid decision it was not to include the medical centrifuge module in the ISS.  Actually,  a spinning space station design would have been even better.  In many ways,  it would appear that NASA and the others had,  and still do not have,  any intention of flying a crew of people to Mars.  If they did,  we would know by now (by direct experiment) whether 0.2 or 0.5 or whatever fractional gee was enough. 

That and all the excuses over radiation exposures are what tell me the government agencies do not want to send men to Mars.  That is why the Dennis Tito 500 day flyby mission may well take place:  to shame the government agencies into actually doing something.  I think the Tito mission may well be a suicide mission (because of microgravity diseases and radiation),  but that is what it may take to spark some serious efforts at NASA and the rest for a Mars landing.  Sad,  but (unfortunately) true,  I believe.

GW


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#14 2013-12-27 20:36:14

louis
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From: UK
Registered: 2008-03-24
Posts: 7,208

Re: Surface centrifugue for a Mars colony

Quaoar wrote:
Decimator wrote:
louis wrote:

1. Procreation will require some extended replication of 1G

What do you base this on?  We have no data between zero and one gee.

Probably 0.38 gee is enough for a correct embryo-fetal development, but as you correctly say, we have no data (if not, it would pose a serious limit on animal breeding)
A one gee facility will be very likely needed for a correct body development of the martian children.

http://io9.com/5664014/making-a-baby-in … l-involved

I think there have been a number of experiments showing the risk to embryo development.


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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#15 2013-12-27 21:03:45

JoshNH4H
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From: Pullman, WA
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Re: Surface centrifugue for a Mars colony

Please note that there is a different between the microgravity environment and the Martian gravity environment, and one cannot necessarily extrapolate from one to the other.


-Josh

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#16 2013-12-28 07:38:44

Quaoar
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Registered: 2013-12-13
Posts: 665

Re: Surface centrifugue for a Mars colony

louis wrote:

http://io9.com/5664014/making-a-baby-in … l-involved

I think there have been a number of experiments showing the risk to embryo development.

You have also to note that the experiments was not performed in microgravity, but in simulated microgravity, with a Earth based device that countinously change orientation, to not have a stable up-down position. So we have only extrapolated data on embryo develpoment in real microgravity, and completely no data on a 0.38 gee low gravity.

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#17 2013-12-28 08:30:34

Terraformer
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Re: Surface centrifugue for a Mars colony

I thought quails had developed fine in microgravity?


Use what is abundant and build to last

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#18 2013-12-28 08:42:57

louis
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From: UK
Registered: 2008-03-24
Posts: 7,208

Re: Surface centrifugue for a Mars colony

Quaoar wrote:
louis wrote:

http://io9.com/5664014/making-a-baby-in … l-involved

I think there have been a number of experiments showing the risk to embryo development.

You have also to note that the experiments was not performed in microgravity, but in simulated microgravity, with a Earth based device that countinously change orientation, to not have a stable up-down position. So we have only extrapolated data on embryo develpoment in real microgravity, and completely no data on a 0.38 gee low gravity.

There have been abnormalities observed - I think it is reasonable to speculate these sorts of abnormality are likely to have negative consequences in highly complex organisms dependent on brain development:

"Abstract
In vertebrates, only few experiments have been performed in microgravity to study the embryonic development from fertilization. To date, these concern only amphibian and fish. We report here a study on the embryonic development of Pleurodeles waltl (urodele amphibian) eggs oviposited in microgravity. The experiment was performed twice on board the Mir space station and the data obtained included video recording and morphological, histological and immunocytological analyses. The data confirm that the microgravity conditions have effects during the embryonic period, particularly during cleavage and neurulation, inducing irregular segmentation and abnormal closure of the neural tube. Moreover, we observed several abnormalities hither to undescribed corresponding to cortical cytoplasm movements, a decrease of cell adhesion and a loss of cells. These abnormalities were temporary and subsequently reversible. The young larvae that hatched during the flight displayed normal morphology and swimming behavior after landing. The results obtained in the urodele Pleurodeles waltl are in accordance with those observed earlier in the anuran Xenopus laevis and in the fish Oryzias latipes."

http://www.ncbi.nlm.nih.gov/pubmed/12101347


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#19 2013-12-28 11:55:52

JoshNH4H
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From: Pullman, WA
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Re: Surface centrifugue for a Mars colony

It's not unreasonable to suggest that human development would proceed poorly in zero gravity. However, it is unreasonable to suggest that we know anything at all about the biological consequences of living in Martian gravity.


-Josh

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#20 2013-12-28 13:18:01

Tom Kalbfus
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Posts: 4,401

Re: Surface centrifugue for a Mars colony

SpaceNut wrote:

100 meter at 3rpm wil get you near the 1g level but what I am concerned about is the fact that we can barely land a 10 meter diameter space craft. That said where are the materials coming from to build something so large and massive. The power drain to move a large mass will be hard to generate. The motor or motors to make it move.

What's the problem can't we spool 200 meters of steel cable and then unwind to spin 2 Orion Capsules to House 8 astronauts? You could have 4 men in one capsule and 4 women in the other, so they don't procreate. The cable itself won't weigh much compared with the capsules and the engine.

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#21 2013-12-28 13:26:08

Tom Kalbfus
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Re: Surface centrifugue for a Mars colony

Oh, you mean a surface centrifuge, not one in space. Didn't read the whole title. What you would need would be something like one of the rides in a traveling carnaval or fair, such as a spinning wheel mounted on a truck. The problem is you'd need to keep parts lubricated to keep them spinning. A tall pole with two habs attached to cables spinning around a common center would be what would be required. I think the astronauts would not want to look out the window too often, it may be a bit unsettling to see the landscape spinning around all the time, and if they want to go outside, they would have to stop the spinning so they can get out. Lets see if you have 100 meters of cable, you would need to mount it on a pole that was 100 meters tall, you'd need an electric motor that is perhaps Solar powered with photovoltaic cells surrounding the spinning habs, at night, you can give the centrifuge a rest and sleep at 0.38 g which actually might be quite comfortable!

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#22 2013-12-28 13:48:33

GW Johnson
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From: McGregor, Texas USA
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Re: Surface centrifugue for a Mars colony

The three things I always see proposed for artificial spin gravity are (1) gigantic battlestar galacticas that spin about longitudinal axes,  (2) cable-connected lightweights,  and (3) truss-connected battlestar galacticas.

Battlestar galacticas are not practical at all at this time in history:  too expensive,  in all senses of the word.  That eliminates ideas (1) and (3).

Idea (2) is almost practical,  except for instabilities and difficulties spinning up and spinning down,  the transients.  Otherwise,  it looks pretty good steady-state.  Proposing to do this with two relatively tiny capsules ignores both living-space-to-stay-sane and radiation shielding for a long voyage (6 months or more 1-way to Mars).  You can better do this with a proper habitat module at one end of the cable,  and something else heavy at the other end (maybe the propellant and engines you have to have,  anyway).  God help you if the cable breaks (meteroid impact!!!),  because no one else can. 

Because of the need to do course corrections,  there will be more than one very difficult-to-execute spin-up and spin-down operation.  More than one of each maneuver vastly increases the probability of an accident,  because these probabilities multiply,  they do not add.  That is why rigid structures are very much preferred for spin gravity designs.  Much lower probability of a transient spin-up or -down instability accident.

There is a 4th idea that can address all of this successfully,  which can easily be implemented with multiple docked propellant tanks,  far more easily than with bigger stages.  Using a combination of serial and parallel docking configurations,  you can always create a long baton,  fatter or skinnier as the number of tanks changes,  with the hab at one end and the engines at the other.  This structure is at least semi-rigid,  quite unlike cable-connected assemblies.  The spin-up/spin-down risks are therefore way-to-hell-and-gone lower than any imaginable cable-connected system.   Doing course corrections is thus way less risky with a more rigid spinning structure,  and the baton shape is well known to be quite stable while spinning (see the twirlers at any football game Friday nights all over the US). 

The trouble with idea (4) (spinning baton) is that it is inherently not amenable to the overly-minimalist configuration proposals.  I don't see that as a serious objection,  because those overly-minimalist proposals ignore the living space and radiation protection issues.  Either is likely to kill crews,  more especially the solar flare radiation.  But insanity also kills,  as we have seen for a long time now with mass shootings by people known to have mental problems.    Ask anyone who has ever served time in solitary confinement about its effects on sanity.  He will confirm what I say about long-term confinement in quarters too close. 

Overly-minimalist proposals being infeasible on the confinement and radiation-protection issues,  I don't see any realistic objection to using the modular ship idea to provide a spinning baton shape for artificial gravity.  Its only problem is that we are forced to design for 1 full gee at the farthest hab deck,  because we do not have one single shred of direct evidence that partial gee will be sufficient.  1 full gee at 4 rpm requires 56 m radius,  scale your ideas from there.  We already know how to build things that docked-module way:  ISS is also docked modules,  and the Saturn-1 first stage had parallel-connected tanks,  and we do strap-on boosters. 

Any spacious hab design will have the room to add water and wastewater tankage in such a way so as to provide a 20 cm water shield around at least part of the hab as a radiation shelter.  Could be externally or internally mounted.  Lots of design freedom there. 

I would suggest using Bigelow-syle inflatables to be docked together to create a really big hab module.  I would also suggest that the packaged core equipment in each module be deployed in such a way as to remain within the core space of the fully-erected inflatable structure.  That way,  access to the pressure shell is unimpeded,  for rapid repair of meteroid punctures.  You cannot afford the time to move stuff out of the way:  it'll depressurize before you can patch it if you clutter the pressure walls.  That same free-access consideration applies to rigid-shell hab modules,  too.  Basic safety "at work" here. 

I would also suggest that the vehicle control station be the radiation shelter.  That way critical maneuvers may be performed no matter the solar weather. 

None of this would yet apply to a surface hab on Mars.  But depending upon what we finally learn about "how much gee is enough",  we might have to add some sort of spinning frisbee shape as part of permanent settlements on Mars and the moon.  No one knows yet.  We can solve that problem if and when it crops up. 

Just ideas and suggestions from an old,  and very widely-experienced,  aerospace engineer.

GW

Last edited by GW Johnson (2013-12-28 14:00:39)


GW Johnson
McGregor,  Texas

"There is nothing as expensive as a dead crew,  especially one dead from a bad management decision"

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#23 2013-12-28 22:23:23

SpaceNut
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Posts: 29,428

Re: Surface centrifugue for a Mars colony

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#24 2013-12-29 04:22:43

RobertDyck
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From: Winnipeg, Canada
Registered: 2002-08-20
Posts: 7,924
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Re: Surface centrifugue for a Mars colony

Once upon a time we had a discussion for Frequently Asked Questions. New comers always ask the same questions. I thought Josh wrote that. What happened to it?

The reason I ask, is the topic of this discussion is one. The reason for going to Mars, is to be on Mars. For humans to go to Mars, the purpose is to live and thrive on Mars, not to be cooped up in a simulation of Earth. If you can't leave without a centrifuge, can't explore the surface, can't mine and harvest resources, always paranoid to protect yourself from every tiny thing that's different from Earth, then there would be no purpose to leave Earth. Medical research leads us to suspect the problem with zero-G (or microgravity) is lack of convection of fluids. Or otherwise, lack of fluid movement due to lack of gravity. That means significant gravity such as 0.38g should solve the problem. Of course you could argue that there is no data to confirm that assertion, the Centrifuge Accommodation Module on ISS was supposed to verify that. But assuming we require a centrifuge on Mars to survive, simply because the Centrifuge module on ISS was cancelled? Um, no! If you're going to go to Mars, then be on Mars.

Last edited by RobertDyck (2013-12-29 04:25:18)

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#25 2013-12-29 04:49:26

louis
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From: UK
Registered: 2008-03-24
Posts: 7,208

Re: Surface centrifugue for a Mars colony

RobertDyck wrote:

Once upon a time we had a discussion for Frequently Asked Questions. New comers always ask the same questions. I thought Josh wrote that. What happened to it?

The reason I ask, is the topic of this discussion is one. The reason for going to Mars, is to be on Mars. For humans to go to Mars, the purpose is to live and thrive on Mars, not to be cooped up in a simulation of Earth. If you can't leave without a centrifuge, can't explore the surface, can't mine and harvest resources, always paranoid to protect yourself from every tiny thing that's different from Earth, then there would be no purpose to leave Earth. Medical research leads us to suspect the problem with zero-G (or microgravity) is lack of convection of fluids. Or otherwise, lack of fluid movement due to lack of gravity. That means significant gravity such as 0.38g should solve the problem. Of course you could argue that there is no data to confirm that assertion, the Centrifuge Accommodation Module on ISS was supposed to verify that. But assuming we require a centrifuge on Mars to survive, simply because the Centrifuge module on ISS was cancelled? Um, no! If you're going to go to Mars, then be on Mars.

I take your general point (as for FAQs - well virtually all the discussions here are FAQs if you want to be grinchy about it) - but I think it is certainly something to consider and prepare for if we are going to take up long term residence on Mars. We can't just overcome the laws of physics through an effort of will.

It might be that eventually we settle for something like sleeping pods at night at 1G (or maybe 1.2 or something) to compensate overall and maintain top health (in combination with weighted body suits to continually stress muscles during the day).


Let's Go to Mars...Google on: Fast Track to Mars blogspot.com

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