# Disadvantages of a short radius centrifuge for gravity simulation in space

For a free-floating space colony, what problems would the residents encounter if the radius of the centrifuge would be significantly less? I recently saw a video on this. It said that after a 10 day training course, people could adapt to low-radius centrifuge going as fast as 17 rpm. So, what are some other disadvantages? And to combat these problems, what would be an ideal radius?

• You might find this link of interest as it allows calculations an also offers a number of references concerning comfort levels under various conditions: artificial-gravity.com/sw/SpinCalc/SpinCalc.htm Commented Mar 24, 2023 at 13:16

A 1 g, 17 rpm centrifuge would only be about 3 m in radius. A typical person's head would be experiencing something close to Mars gravity when they were standing. Coriolis effects would also be extreme.

You might be able to sleep in such a centrifuge, but this would be little different from staying in bed on Earth, which is actually used to approximate the effects of microgravity for medical studies. You need to be able to stand and stress the body under centrifugal gravity to get the benefits. This will require something a bit larger.

• while I was looking into various design concepts for ships intended for long term space habitation I came across quite a lot of research that helped understand human sensitivities. One particularly troublesome effect is coreolis effect within the inner ear 'unbalancing' people, making people stumble and fall when walking in certain direction relative to centrifuge rotation. The smaller the radius the bigger the problem. Commented Nov 16, 2022 at 21:32
• Hello, thank you for answering! I just gave that number as a maximum cap. I just wondered if i could create a centrifuge as large as, say 25 or 50 m on an asteroid to extract minerals. And if such short-spin centrifuges could be feasible, then an experimental centrifuge could be setup in space with a radius of, say, 10-20 m for long term testing! Commented Nov 18, 2022 at 13:25

Realistically artificial gravity should allow for 'normal' activities, walking, working, eating, bathroom etc. Short arm, high rpm centrifuges do not. NASA testing has shown that rapid (a couple of days) acclimatisation is possible with speeds up to 8rpm, less than 3 rpm is comfortable within hours.

This is a good reference: A Review of Challenges & Opportunities: Variable and Partial Gravity for Human Habitats in LEO

• Can you link to any sources talking about that NASA testing? Commented Mar 24, 2023 at 5:57
• Please look through this report "A Review of Challenges & Opportunities: Variable and Partial Gravity for Human Habitats in LEO" sorry I don't have the link to hand Commented Mar 24, 2023 at 12:00
• I added the link, but I am not sure it supports the OP's claims. A quick search found no reference to "8 rpm". Some direct quotes supporting the claims would be useful. Commented Mar 24, 2023 at 13:22
• Section 6.2.6 is as close as I found, e.g. “When rotation ranges from 3 to 6 rev/min ... the initiation of rotation will elicit changes in postural equilibrium as well as symptoms of motion sickness, the extents of which are a function of the magnitude of the angular velocity. Nevertheless, adaptation can be achieved under these conditions in 6 to 8 days, and the remainder of the stay in the rotating environment is characterized by normal health and performance” (Diamandis, 1997). I didn't see immediately anything in that section to support less than 3rpm Commented Mar 24, 2023 at 19:37