Reading an article on terraforming of Mars, saw the below and wondered, with current technology either here on in space, could we simulate .38G to see what effects is has on health. You could I assume create a rotating space station that would simulate it so perhaps I answered my own question, I wonder if you could have a space station where you can vary the gravity by how fast it spins.

The surface gravity on Mars is 38% of that on Earth. It is not known if this is enough to prevent the health problems associated with weightlessness.

Cymek said:

Reading an article on terraforming of Mars, saw the below and wondered, with current technology either here on in space, could we simulate .38G to see what effects is has on health. You could I assume create a rotating space station that would simulate it so perhaps I answered my own question, I wonder if you could have a space station where you can vary the gravity by how fast it spins.

The surface gravity on Mars is 38% of that on Earth. It is not known if this is enough to prevent the health problems associated with weightlessness.

They could wear heavy shoes / clothing to make up for the rest.

I think that the radius of such a spinning ship would have to be quite large in order to simulate gravity in any meaningful way…

furious said:

I think that the radius of such a spinning ship would have to be quite large in order to simulate gravity in any meaningful way…

a rope with the ship on one end and a weight on t’other.

Cymek said:

Reading an article on terraforming of Mars, saw the below and wondered, with current technology either here on in space, could we simulate .38G to see what effects is has on health. You could I assume create a rotating space station that would simulate it so perhaps I answered my own question, I wonder if you could have a space station where you can vary the gravity by how fast it spins.

The surface gravity on Mars is 38% of that on Earth. It is not known if this is enough to prevent the health problems associated with weightlessness.

Hmm, interesting question. I would expect it to be plenty to prevent healtg problems duebto weightlessness.

Standing waist deep in water would be a start, but not good enough. What about lab rats in a centrifuge in space.

Let’s consider rotating spacecraft, like 2001 a space oddysey.

Acceleration = omega^2 * r
3.7 m/s^2 = 2 (radians per second)^2 * 0.9 metres
3.7 m/s^2 = 1.5^2 * 1.65
3.7 m/s^2 = 1^2 * 3.7

None of those rotation speeds are particularly fast or distances particularly large. 1 radian per second is 10 rpm.

furious said:

I think that the radius of such a spinning ship would have to be quite large in order to simulate gravity in any meaningful way…

Or spin it real fast.

The Zubrin-Baker plan of 1991 suggests using a tethered weight, rather than having a ship of huge radius.

e.g Have your craft attached to a weight on a cable some hundreds of metres long, giving you a long effective radius of rotation.

Z-B imagined this for being in use in transit to and from Mars: fire it up using minor rocketry on both the craft and the ballast for the journey at 0.38 g to get folks enured to Mars gravity on the to-journey, then dispose of the ballast prior to Mars landing. On the return journey, you could start at 0.38 and ramp up to 1.0 g and then again discard the return vehicle’s ballast before entry.

There’d be no reason you couldn’t use such a system in Low Earth Orbit though. If you needed to dock you can fire the rocketry to slow and stop the spin, then after you’ve finished, fire it up again.

I’m sure a lot of astronauts would prefer to be able to use the toilet like a normal person…

In the example below, the effective radius of rotation at the centre of the craft is 100 metres. The red dot is the centre of mass. There would be a small variation in acceleration around different parts of the craft but not excessively. To obtain a Mars gravity you’d need a rotational period of around 32 seconds.

To be honest I’m a bit disappointed that no one has done this in LEO to find out the effects of reduced gravity on the human body. We have years and years, about 150 person-years, of data of the effects of zero gravity (or technically microgravity) on the human body, but nothing at all on the effects of 0.38 g, or 0.16 g.

dv said:

The Zubrin-Baker plan of 1991 suggests using a tethered weight, rather than having a ship of huge radius.

e.g Have your craft attached to a weight on a cable some hundreds of metres long, giving you a long effective radius of rotation.

Could the ballast be a battery pack? That way you could reduce the launch weight requirements at both ends (once the battery is built).

Lary said:

dv said:

The Zubrin-Baker plan of 1991 suggests using a tethered weight, rather than having a ship of huge radius.

e.g Have your craft attached to a weight on a cable some hundreds of metres long, giving you a long effective radius of rotation.

Could the ballast be a battery pack? That way you could reduce the launch weight requirements at both ends (once the battery is built).

I … guess? I’d be wary of putting any critical hardware on it.

dv said:

Lary said:

dv said:

The Zubrin-Baker plan of 1991 suggests using a tethered weight, rather than having a ship of huge radius.

e.g Have your craft attached to a weight on a cable some hundreds of metres long, giving you a long effective radius of rotation.

Could the ballast be a battery pack? That way you could reduce the launch weight requirements at both ends (once the battery is built).

I … guess? I’d be wary of putting any critical hardware on it.

I thought water supply but then it would diminish in mass over time.

• I thought water supply but then it would diminish in mass over time.

I would think that the water could be recycled back. But it would be easier to transfer the contents of a battery to the ship than the contents of a water supply…

dv said:

Z-B imagined this for being in use in transit to and from Mars: fire it up using minor rocketry on both the craft and the ballast for the journey at 0.38 g to get folks enured to Mars gravity on the to-journey, then dispose of the ballast prior to Mars landing. On the return journey, you could start at 0.38 and ramp up to 1.0 g and then again discard the return vehicle’s ballast before entry.

There’d be no reason you couldn’t use such a system in Low Earth Orbit though. If you needed to dock you can fire the rocketry to slow and stop the spin, then after you’ve finished, fire it up again.

It’d be a lot more fuel efficient for the craft docking to approach the red dot along the axis of rotation, match the rotation and then attach to the cable with some grapple mechanism with rollers, rotate through 90° and then, with a tiny nudge, start to move along the cable to dock side on with the big ship.

Ian said:

dv said:

Z-B imagined this for being in use in transit to and from Mars: fire it up using minor rocketry on both the craft and the ballast for the journey at 0.38 g to get folks enured to Mars gravity on the to-journey, then dispose of the ballast prior to Mars landing. On the return journey, you could start at 0.38 and ramp up to 1.0 g and then again discard the return vehicle’s ballast before entry.

There’d be no reason you couldn’t use such a system in Low Earth Orbit though. If you needed to dock you can fire the rocketry to slow and stop the spin, then after you’ve finished, fire it up again.

It’d be a lot more fuel efficient for the craft docking to approach the red dot along the axis of rotation, match the rotation and then attach to the cable with some grapple mechanism with rollers, rotate through 90° and then, with a tiny nudge, start to move along the cable to dock side on with the big ship.

Never ever simulate gravity using 1 g in space. It’s a crushing weight on Earth, I’m sure all humans would live longer under a lower gravity.

Yes, tethered weight would work. It’s an annoyance that the dozen or so tether experiments so far in space have all failed, possibly because steel cables can’t absorb significant impact loads. I prefer bungee cables – safer.

Z-B = Zaphod Beeblebrox? LOL.

The main way used on the space station is an exercise station – that substitutes well for zero gravity. Another way that was trialled was using the pressure difference between air and vacuum to simulate gravity.

Sloping bed?