Do astronauts feel their weight in orbit?

Question

Will astronauts in space stations such as the International Space Station which orbits the Earth feel their weight?

No, but they feel their mass. This question may fit better at [Physics.SE]. — gerrit, Aug 07 '13 at 11:36

score 3 · Accepted Answer · 2013-08-07T14:39:50.137

No, because they are basically in free fall, as they are constantly accelerating - just as if you had jumped off of an airplane - you would feel weightless, as gravity can move you exactly as it wants.

Now, how does it work that the space station doesn't 'fall into' earth? Well, it basically falls 'around' Earth - which is how any orbit works.

orbit

^{Image credit Wikipedia.}

In this image, the big blue dot is the ISS, while the little dot is the Earth (don't ask me why.) As you can see, the ISS has velocity tangential to it's orbit - it wants to fly off into space.

Now, think of the Earth's gravity as a string - it's basically a force that really wants to keep the space station a certain distance away, for all intents and purposes here.

Now imagine you have, down on Earth, one of those rubber bouncy balls with a hole drilled through it and a string through that hole. If you start the ball moving tangentially to the circle the string would make, the ball would travel along that circle. If there wasn't any friction, the ball would just keep doing this... just like the ISS.

Why is the little dot the Earth? – dotancohen Aug 07 '13 at 14:37 — dotancohen, Aug 07 '13 at 14:37
@dotancohen Don't ask me - I didn't make it. – Aug 07 '13 at 14:37 — , Aug 07 '13 at 14:37

score 1 · Answer 2 · answered Aug 07 '13 at 13:51

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No. They're in freefall. They don't weigh anything as a result.

answered Aug 07 '13 at 13:51

Dan Is Fiddling By Firelight

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score 1 · Answer 3 · answered Aug 07 '13 at 14:26

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Yes! The astronauts do in fact feel their mass (not technically their weight) when they try to move themselves or other objects. You can watch videos of astronauts unpacking the SpaceX or Progress vehicles, and when they move packages it is quite obvious that both the packages and the astronaut move about as a reaction.

answered Aug 07 '13 at 14:26

dotancohen

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Now I'm confused as to what the question was asking for :( – Aug 07 '13 at 14:33
Why the downvote? I feel that I addressed the question directly, and gave real-world examples. – dotancohen Aug 07 '13 at 16:18
It's not mine, I promise. I'll give you an upvote, though, for adding relevant information. – Aug 07 '13 at 16:20
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Thanks, Undo. I'm not worried about the rep, but I am worried about the viability of space.SE if people will just come along and downvote without explanation. That leads to frustration and nobody is going to voluntarily contribute to the forum if it is frustrating. Trolls ruin it for everybody. – dotancohen Aug 07 '13 at 16:37
Yes, but I have been seeing much less of it than on other sites, like SO/F/U. Also, I imagine that the downvote was because the question asked weight and you answered mass. I actually seriously considered downvoting, but thought that your answer did add value. – Aug 07 '13 at 16:49
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the british english idiom "feel one's weight" is usually used in connection with activity, indicating it's actually mass that's being felt – Sep 23 '17 at 08:44

Do astronauts feel their weight in orbit?

3 Answers3