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Am I correct in assuming it is near impossible for astronauts to stand still inside the ISS, even if their feet are secured under a blue IVA rail?

NASA astronauts Terry Virts' foot under a blue IVA rail

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This video "Space Station Boost Proves Newton's Laws - All 3 of Them!" shows the astronauts while the station is being boosted into a higher orbit, and they are trying to remain still. While they are moving away from the camera do to the acceleration of the station, the are rotating on different axes either once they let go of something or they bring their legs up into a tuck.

Wouldn't the slightest muscle twitch or other movement would prevent them from standing vertically, unwavering, for any length of time.

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  • $\begingroup$ Define "stand still". Velcro or magnetic boots would seem to meet a basic definition. $\endgroup$
    – Carl Witthoft
    Commented Jan 6, 2020 at 13:50
  • $\begingroup$ @ CarlWitthoft Stand still/stand at attention-"Keep the head erect and face straight to the front with the chin drawn in so that alignment of the head and neck is vertical." armystudyguide.com/content/Prep_For_Basic_Training/…. Velcro or magnetic boots would keep astronauts feet in one place, but what would prevent them from swaying in different directions and not remaining vertical/at attention? $\endgroup$
    – Bob516
    Commented Jan 6, 2020 at 14:53

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Using the blue rails, you could stand at attention easily, using your foot and ankle muscles.

But for the more interesting case, you could absolutely stand still at attention in the ISS without touching the sides*

(* for a short period of time)

To expand on this a little - assuming you want to do this in a gap between the ISS's thrusters firing, you could get relatively stationary, either with the help of crewmates or by holding onto one of the wall handles with your other arm in a compensating position and then bring arms to an attention position.

You are right that muscle twitches, breathing etc will make you move, as will air movement in the ISS, but for a minute or two you can stay pretty stationary. Conversely, you could use small movements to help maintain your position. Even breathing out could be used to combat a small forward rotation.

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    $\begingroup$ didn't they try blowing and found it not to be terribly useful? $\endgroup$
    – user20636
    Commented Jan 6, 2020 at 12:40
  • $\begingroup$ @RoryAlsop But wouldn't using foot and ankle muscles produce a swaying of the body as the astronauts make each adjustment? When standing at attention on Earth don't we make minor adjustments with those, and I assume other muscles, to return our body to an unstable equilibrium point. Without an unstable equilibrium point in microgravity, wouldn't the astronaut most likely keep on swaying back and forth through the vertical line that would define standing at attention? $\endgroup$
    – Bob516
    Commented Jan 6, 2020 at 14:21
  • $\begingroup$ @JCRM - yes, they confirmed it was not good for propulsion, but to combat minor rotation, you could still use it. We are talking very minor movements here $\endgroup$
    – Rory Alsop ♦
    Commented Jan 6, 2020 at 14:29
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    $\begingroup$ @LeoS - yes, that whole question on how to move (swim, blow, throw a boot etc) was about that. I was being realistic about the ability to position with absolutely zero velocity wrt the ISS, but yes, that short period of time may be minutes :-) $\endgroup$
    – Rory Alsop ♦
    Commented Jan 6, 2020 at 14:36
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    $\begingroup$ @Bob516 this answer describes a real-world test of escaping from being "stranded" space.stackexchange.com/a/18485/6944 $\endgroup$
    – Organic Marble
    Commented Jan 6, 2020 at 19:44

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