Massive ground based centrifuge.

[Comrade Jenkens]

I've seen things recently about SpaceX wanting to take people to Mars, (I think that they are being more than a tad optimistic but that a whole different topic), but the effects of 40% gravity on long term human health are still unknown. I'm wondering if a very large, ground based centrifuge could be constructed to act as a habitat to make up for the lack of gravity on the surface?

[Tommygun]

That's a lot of weight to carry to Mars. I think space agencies would be better off in the long term funding research into medical treatments for things like Osteoporosis and sport medicine to reduce and reverse the effects.

[Tex]

True.

In fact, I think that it would be a thousand times cheaper to send construction specialists and mining companies to Mars to manufacture anything like a huge centrifuge, rather than trying to bring it to there from here.

Even with that said, it would still be outrageously expensive and would probably take quite a few years (or decades) for such a thing to be finished.

[Winter Man]

You'd be better off if you're that concerned just building a variable speed centrifuge in orbit. Stick a bunch of people in it and see what happens.

[Idobox]

There is also a cheaper way to way simulate a stronger gravity : weighted clothes. Imagine tight clothes that happen to weigh about as much as you, the weight would be distributed rather evenly, and simulate normal gravity quite well.

Of course, your inertia would be double as well, which might take some getting used to, but still much cheaper and safer than a giant centrifuge.

[Nibb31]

We don't know if partial gravity is a problem or not, so it's a bit premature to start planning on megastructures to solve what might not be a problem.

I suspect that even a small amount of gravity is enough to allow the body to function normally. But it needs proper investigation.

[K^2]

There is also a cheaper way to way simulate a stronger gravity : weighted clothes. Imagine tight clothes that happen to weigh about as much as you, the weight would be distributed rather evenly, and simulate normal gravity quite well.

Of course, your inertia would be double as well, which might take some getting used to, but still much cheaper and safer than a giant centrifuge.

It's not that simple, unfortunately. I'm sure it'd help, but evenly distributed weight throughout your body is not exactly the same as weight you wear on your body. One problem that jumps immediately to mind is blood circulation. You heart has to constantly combat gravity to pump blood into your brain and out of your legs. At 40% gravity, heart wouldn't have to work nearly as hard. That can cause all sorts of problems, including serious ones like arrhythmia. It might be possible to offset that with exercises, of course, and it might be possible to deal with all of the effects of 40% gravity, but my point is that it's not going to be as simple as wearing a weighted suit. Though, that may be a start.

Nibb31, there are, without a doubt, problems with low gravity. What we don't know is how severe they are, and which ones are reversible. But I completely agree with Winter Man that a variable gravity setup in orbit would be a good way to start looking into it.

Edited April 18, 2014 by K^2

[Winter Man]

You heart has to constantly combat gravity to pump blood into your brain and out of your legs. At 40% gravity, heart wouldn't have to work nearly as hard.

That in mind, it doesn't have to combat gravity at all when you're asleep. It's quite possible the body can adapt just fine to that particular issue. But yeah, I agree with me too. Big test facility in orbit, people just going about their 'daily lives', as it were.

[K^2]

People spending too much time laying down having serious heart troubles is part of the reason I'm sure there will be problems. It's fine if you sleep 8 hours a day. But if you're horizontal 24/7, it's bad.

[Simon Ross]

In the case of Mars, I think the benefits of low G probably outweigh the problems. We certainly know that zero G can cause very serious health problems for long duration crew, however I suspect these problems pretty much disappear at a reasonable fraction of Earth's gravity which Mars certainly has.

On the plus side, much less wear & tear on your heart, joints, ligaments,

[Sirrobert]

I doubt we'd need a really big one.

For the same reason that sleeping 8 hours a day doesn't cause problems, if they'd push gravity a few hours a week (maybe a smaller centrifuge)

I'm pritty sure off one thing:

Colonist that live on Mars for a long time will have significant problems adepting back to life on Earth, even if they might have no problems with life on Mars

[Nuke]

i have a feeling we will use ground based centrifuges if we decide to expand humanity by colonizing the oort cloud. find an object drop in a large ground centrifuge (since gravity is scarce out there) and a fusion reactor. when the colonny begins to show signs of overpopulation some of them set up a colony on the next object. this is the slow way of colonization, sort of like a generation ship, without the ship, and while scattering outposts of humanity all over the place.

i imagine the best way to build one on the ground is to have a tunnel boring machine cut out a circular tunnel under the surface (far enough to protect from radiation), then build modular habitats on maglev tracks in the tunnel. you can build and add modules over time as the population grows, until you fill in the ring. this would be more troublesome in some places than others, icy bodies would be easier to bore through than rocky ones, and tbms are massive hulking beasts that need some infrastructure to operate. so dont expect seeing these till we have considerable off world manufacture.

Edited April 18, 2014 by Nuke

[Tommygun]

I seem to recall that one of the ways that they study the effects of low gravity on Earth is to have volunteers lay in bed for a month or so to see how it affects the body.

Edit: I found a brief article.

http://www.nasa.gov/exploration/humanresearch/analogs/research_info_analog-bedrest.html#.U1GsD1fAsV8

Personally I think the negative effects will just happen slower in low gravity and they will end up having to use exercise and medication to counter the problem.