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Why have I not seen any spin gravity testing in space? Or, more accurately, artificial gravity created through centrifugal/centripetal force. I haven't heard of any tests in standalone spacecraft or attached to the ISS, or any station.

Many far future sci fis have massive spinning cylinder ships and stations, multiple km long. But what about the precursors to this... or simply those more realistic in terms of cost and materials needed, such as:

  • Cheapest: wire tethered capsules, such as Mars Direct ideas by R Zubrin: enter image description here
  • 2nd Cheapest?: spinning stiff trusses with capsules at each end: enter image description here
  • Quite costly: spinning rings: enter image description here

I've seen centrifuge tests done on the earth surface (which overpower Earth g but cannot eliminate it), but have seen none attempted in space so far. Space allows testing of Lunar and Mars levels of g. The tethered capsule could even be a very small setup for lab rats. This seems hugely important for longer duration space travel, considering all of the bad effects of microgravity. A tether could be sent up and attached to spin existing small containers or entire ISS modules. Or SpaceX Dragon capsule with its spent booster as counterweight.

The math and mechanics are not a problem. Getting materials strong enough at reasonable launch weights isn't a problem. Controlling the spin through motors and/or thrusters should not be a problem. Tests could start at days long, then weeks, then months, and so on.

Even small, relatively cheap steps haven't been taken to space, such as 1-2 tiny capsules of lab rats spun on say 30-50m of light cable, near the ISS (not even attached to it, to avoid any disruptions such as vibration). Or anywhere in LEO, with plenty of sensors and cameras inside to monitor things.

It seems very feasible... so I ask, why have I not seen spin gravity testing done in space? (I looked, I swear :D)

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    $\begingroup$ Highly related, possible duplicate space.stackexchange.com/q/1308/6944 $\endgroup$ Mar 17 at 2:56
  • $\begingroup$ That does not address the low cost methods of wire cables or trusses $\endgroup$
    – Koon W
    Mar 17 at 3:10
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    $\begingroup$ Interesting question! I've wondered the same thing. Why zero progress on this front? Humans aren't built for long stretches in microgravity and the only practical way to reproduce gravity on a spaceship seems to be centripetal forces. So why no tests? Why no progress? I find hard to believe we'll ever truly be a spacefaring species without some means to reliably reproduce gravity in space. It just won't happen, full stop. $\endgroup$
    – user39728
    Mar 17 at 3:16
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    $\begingroup$ I've heard it claimed that gravity tethers tend to build up vibrations. Also, the minimal viable spacecraft to experiment with this is kind of big. $\endgroup$
    – ikrase
    Mar 17 at 5:54
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    $\begingroup$ You're assuming that's the author's intent @uhoh. It may be that the question is answered by the other post. $\endgroup$
    – GdD
    Mar 17 at 8:38
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Even small, relatively cheap steps haven't been taken to space

Leaving aside the idea that there's such a thing as "cheap" in space: Sept. 14, 1966 - Gemini XI Artificial Gravity Experiment

Gemini XI separated from the Agena with their spacecraft pointed nose-down toward the Earth. Conrad and Gordon maneuvered their craft to keep the tether taut between both. By firing their side thrusters to slowly rotate the combined spacecraft, they were able to use centrifugal force to generate about 0.00015 g. "There is an artificial gravity field," Gordon said. "It makes the camera move back very rapidly." The tether was released following two orbits of the artificial gravity experiment, allowing Gemini and Agena to go their separate ways.

Gemini XI artificial gravity experiment

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