Do astronauts become weightless as they leave Earth or is there a point they feel weightless?

  1. There is a sudden point at which astronauts immediately feel weightless — it is the moment when their rocket engine shuts off and their vehicle begins to fall.

    Remember, Folks in the ISS are just over 200 miles farther from Earth’s center than you are — that’s about 4% farther out, so they experience about 92% as much gravity as you do.

    All those pictures you see of people floating around the ISS aren’t faked, it’s just that the ISS is falling. The trick of being in orbit is to zip sideways fast enough that you miss the Earth instead of hitting it.

  2. It seems a lot of these answers aren’t addressing the first part of your question, which has the common misunderstanding that there is no gravity in orbit. The weightlessness experienced by astronauts is, as others noted, due to the free fall they are in once they enter orbit. So yes, there is a sudden point when they feel weightless when the rocket stops firing. The gravitational pull of the Earth however has not changed much–it is almost as strong in low earth orbit as it is on the ground. In other words, their weightlessness has nothing to do with the Earth’s gravitation pull getting smaller since that is a flawed assumption.

  3. [This page] (http://history.nasa.gov/ap15fj/01launchtoearth_orbit.htm) shows a graph of g-force on Astronauts during a Apollo launch (go to almost the bottom of the page), which is interesting, as the g-force drops to zero in between each stage firing. The graph does start at 1 g, so I assume the zero-g is “really” zero g for those instants between stages.

    As long as engines are firing, there is some g-force. When they stop firing between stages, there is no force and the ship is (temporarily) in free fall, though already going so fast that the -9.8 m/s2 does not have enough time to cut the speed much before the next stage fired. Though I could be wrong on this point, but you can still be “in free fall” while going up. If you could skydive out of a jet shooting high up very fast, you would be in free fall and “weightless” even though you are still flying upward for a few seconds, depending on the plane speed.

  4. You can be in space without feeling weightless, and you can feel weightless without being in space.

    Try this: grab a dense, small object, like a beanie baby or your wallet. Jump really high on a trampoline, and on your highest jump, about halfway up, let go of the object. Don’t throw it, just hold it in front of your face, and let it go.

    Then, watch its movement relative to your hands. It will appear to float for a moment (until you land). That’s because it is in freefall just you are.

    An orbit is nothing more than a falling object, just like you are on that trampoline, so anything orbit appears weightless from the perspective of itself.

  5. Astronauts become weightless not because there’s no gravity, but because in orbit they’re technically in free fall. Gravity is still 80% up on the ISS IIRC.

    So you’d feel gravity as long as your rocket was accelerating upwards, then the moment the engines cut out you’d become weightless.

  6. I think you might have a misconception that the reason you become weightless is that you leave the earth gravitational field. This is not true and the difference in gravitational pull between the ground and the ISS is minimal. The major reason is that you are falling. It is the same when you are in free fall on earth. You feel weightless. So the point you fall weightless is when you start falling (or start orbitting).

  7. The weightlessness on the ISS you’re talking about is not due to being so far out that Earth’s mass has a negligible gravitational pull. It’s because the ISS is “falling” (i.e. constantly accelerating (i.e. constantly changing direction)) in a circle.

    However, if you were to ride a spaceship away from Earth in a straight line then, yes, you would feel a Earth’s gravitational pull diminish with respect to the distance between you and Earth squared. (Note, however, that such a ship is likely to be accelerating very, very quickly. About 3 Gs, give or take. This is a very large acceleration, so whether or not you would actually feel this difference during travel is questionable. However, an appropriate measuring device would, in fact, see Earth’s gravitational pull diminish as the ship traveled away from Earth.)

  8. Astronauts will feel weightless as soon as they are in free fall. Anytime the engines are firing, there will be a certain G force they will be experiencing. Interestingly, if you simply jump into the air, you’re “weightless” for a split second, because you too are in free fall.

    The reason that astronauts are weightless for days, weeks, or months on end in the Space Station is because it is in a perpetual free fall called an orbit! =)

  9. Add-on question: Does the weightlessness or freefall feel like being on an airplane when it suddenly hits the low pressure pocket and everything freefalls down for a few seconds? In other words, is it really like falling (but without the air brushing past you)? If so, how can astronauts deal with it so easily? Every time I’ve experienced momentary freefall (on planes, Hollywood Studios Tower of Terror, or just jumping down from somewhere) it makes me queasy. I’d love to float around in space but I don’t want to fall non-stop.

  10. ok, so since we all understand that astronauts are actually experiencing free fall and not weightlessness, is there any difference between that feeling and what they would experience if they were millions of miles from earth?

  11. I was asking about the travel between not the actual approach. Perhaps the Moon was a poor example.

    Pretend you are traveling a far distance in space and just need to accelerate once or twice and the ship travels straight (because there is no air resistance to slow you). Are you still ‘falling’ or are you now being pushed and the side of your rocket with the thrusters on it is now ‘down’ and would you be able to walk around? Would this be possible only as you were accelerating?

  12. The feeling of “weightlessness” is just the experience of all of your component particles being moved equally. Ironically, gravity is the only force which is sort of capable of affecting all of your components equally (there is very slight compression always occurring), so you feel weightless when the only force acting on you is gravity.