Question about maintaining centrifugal force

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Discussion Overview

The discussion revolves around the concept of maintaining centrifugal force to simulate gravity in spacecraft or space stations through rotation. It explores the feasibility of using spinning structures, such as a long cable or a rotating ring, to create artificial gravity, as well as the implications of movement within these structures and the need for propulsion to maintain rotation.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant suggests that movement within a rotating spacecraft or station could shift the center of mass, potentially leading to unexpected effects that would need compensation.
  • Another participant proposes that, due to the lack of air resistance in space, there may be little need to boost the rotational speed, although adjustments might be necessary to counteract solar wind effects.
  • A follow-up question is raised about the possibility of initiating rotation using a reaction wheel or control-moment gyro, questioning the feasibility of this approach.
  • There is curiosity expressed regarding why such artificial gravity methods have not been attempted in space, with a calculation provided suggesting that a specific RPM could simulate Earth's gravity.

Areas of Agreement / Disagreement

Participants express differing views on the necessity of maintaining rotational speed and the methods for initiating rotation. The discussion remains unresolved regarding the practicality and implementation of these concepts in actual space missions.

Contextual Notes

Assumptions about the effects of movement on the center of mass and the specific calculations for RPM are not fully explored or validated within the discussion.

FlyingKiwi
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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
 
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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.
 
UltrafastPED said:
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
 

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