Why do astronauts move so slowly in zero gravity?

  • When astronauts are floating about in a spaceship or space station, they nearly always move very slowly. After doing a bit of research I can't see why being in zero gravity would restrict movement to such a degree. It's almost as if there's resistance to their movement, like they're moving through water.


    This is mostly a question about [movies.se] and partly a question about [space.se], but it seems to have nothing at all to do with astronomy.

    I'm voting to close this question as off-topic because this does not have anything to do with astronomy.

    I think it could be re-worded to be more about space exploration, like, how people would move once they got acquainted with zero g or asking how fast astronauts move. I've seen videos of them moving pretty fast in orbit.

    always move slowly? not always though it looks pretty slow as it's a large space.

  • Rory Alsop

    Rory Alsop Correct answer

    3 years ago

    It's more for safety than anything else. Space is a very dangerous place for so many reasons. And making mistakes can very easily cause death.



    Being weightless does not mean you lose mass, so momentum is just as difficult as ever. But whereas on the ground you can easily use friction to stop, in space if you try to stop against the floor you will just move off it. You can only stop by holding something, or pressing against something close to perpendicular to your movement.



    As an example, imagine you jumped with all your force from one wall in the ISS. You will notice as you approach the other end that you are travelling at speed, head first, with no safe way to stop. Even reaching out to a handhold on a side wall will whip you round and into that wall, possibly injuring yourself or damaging instruments on the wall.



    Look at any video from the ISS to see how carefully they move.



    Similarly, outside the ISS, you want to do everything slowly so you don't damage your suit, miss a handhold or otherwise cause death.


    This reminds me of the way some people commented the movie Gravity. Some characters were moving at relatively high speed in their suit, and tried to grab something to stop themselves. The people commented how they should have lost their arm, considering they were weighing several tons with the suit.

    @Clockwork An astronaut wearing one of the suits used on the space shuttle, including the life-support backpack, weighed about 500lbs, which is about a quarter of a ton, not "several tons". (Source: NASA; see page 4 of the PDF.)

    @DavidRicherby Well, guess my memory (and my lack of knowledge on the matter) tricked me. Still, a quarter of a ton still sounds heavy for a human-being to throw themself without getting crushed on impact.

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