Why do things float on the space station?

16 June 2015


The International Space Station (ISS) in orbit, photographed from the attending space shuttle Discovery



If gravity holds the space station in orbit then why is it 0g inside?

If gravity can hold the space station in orbit, than why does the supposedly from space tele- visit always shown as 0g. Wouldn't gravity be present in an orbiting body? Even minutely! the why don't the interviewed bodies fall towards the gravity holding the spacecraft in orbit?


Science humourist Dave Zobel had a go at answering Terry's question...

Dave - Why do the astronauts float about? If they just put on heavy boots, wouldn't they be able to stomp around like the rest of us?

The brief answer Terry, is the same reason that when you jump off of a very high building with your keys in your hand - which I don't recommend - as you are descending to the Earth, your keys sort of float up from your hand. They don't stay anchored in your hand and the things that are in your pockets don't stay anchored there.

And the reason for that is because you and your keys, and everything else are all falling at the same time and at the same rate; well that's what's going on with the International Space Station and really, anything else in orbit.

You are falling not to the Earth but around the Earth, but it's the same idea. And everything is falling. So, it's all falling at the same rate.

That's also the reason that when astronauts train in the aeroplane known colloquially as the "vomit comet" where they go up and then come crashing down towards the Earth and then, at the last moment, pull out and go up again; and do that over and over, and over until everybody has had the chance to see what everybody else had for breakfast. There's that same weightless period and that gives them 20 or 30 seconds to be able to float around and feel what it's like to be in the International Space Station.


So you are saying on space walks they are falling 1000 mph? So then if there is no surrounding ship to fall faster than the body how does it produce the feeling of weightlessness, or how does a body fall at the same rate as a space station?

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