Question about maintaining centrifugal force

[FlyingKiwi]

Hey all,

I recently read a bit about proposals to induce "artificial gravity" on a Mars mission by spinning two sections of a spacecraft on a long cable in order to create a centrifugal force that would simulate gravity by pulling astronauts outward toward the floor of their capsule, or, similarly, a space station that consisted of a very large ring spinning at a certain RPM. My initial thought is that as people moved around within the spacecraft or station, it could shift the center of mass, thereby causing some weird effects that would have to be somehow compensated for, though perhaps I'm mistaken in assuming this.

My question is whether or not the rotation of the said objects would be maintained, or if additional propellant would be required to periodically "re-boost" the rotation of a station or spacecraft in order to maintain the desired RPM? Thanks!,

-FK

 

[UltrafastPED]

The usual proposal is to have two (or more) balancing arms, or even a ring, that is revolving.

Since there is no air resistance in space, there should be little need to boost the rotational speed, but there will be attitude adjustments due to the solar wind.

 

[FlyingKiwi]

The usual proposal is to have two (or more) balancing arms, or even a ring, that is revolving.

Since there is no air resistance in space, there should be little need to boost the rotational speed, but there will be attitude adjustments due to the solar wind.

Interesting, thanks. Two more questions:

- Could the rotation of the station/ spacecraft be initiated by a reaction wheel or control-moment gyro like many satellites use? If not, why?

- Any idea why this hasn't been attempted in space? It doesn't seem like one would need to add a significant amount of mass to the orbital payload in order to get, say, a 100-meter cable into orbit that could attach a spent booster to a spacecraft . Assuming the center of mass was exactly between the two objects, if I've calculated this right, you'd only need an RPM of 4.2 to induce a centrifugal force equivalent to that of Earth's gravity at the surface (if R = 50m, V = 22 m/s)


Thanks!

-FK

 

[UltrafastPED]

You can find quite a lot of information here: https://en.wikipedia.org/wiki/Artificial_gravity

The method is a very standard science fiction trope.

 

[PJC01]

Hello FK,

Thank you for your question about maintaining centrifugal force in a spacecraft or space station. Your initial thought is correct, as the movement of astronauts or objects within the rotating structure can shift the center of mass and cause changes in the centrifugal force. In order to maintain a constant and stable centrifugal force, additional propellant or other means of energy would be required to periodically re-boost the rotation of the station or spacecraft.

One proposed solution to this issue is to use a flywheel or other mechanical device to store and release energy, similar to how a gyroscope maintains its rotation. This would reduce the need for constant re-boosting and could potentially make the system more efficient.

Another option is to use a closed-loop system where the rotation is continuously monitored and adjustments are made to maintain the desired RPM. This would require precise control and monitoring systems, but could also reduce the need for additional propellant.

Overall, maintaining centrifugal force in a rotating structure in space is a complex issue that would require careful planning and engineering. I hope this helps answer your question. Good luck with your research!

Best,