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Like in the movies a spacecraft just stays in someplace without orbiting anything?

This is distinct from geo-synchronous orbit, where the object orbits, but looks like it is standing still from the ground.

With sufficient power, can you hover in place, but not via orbital velocity?

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    $\begingroup$ Please give 1 (one) example where a spaceship in a movie is not orbiting anything. With proof, please. $\endgroup$ Dec 28, 2021 at 13:20
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    $\begingroup$ It may take centuries to complete one revolution around central body, you can't notice that in 5 seconds of movie. $\endgroup$
    – Naktibalda
    Dec 28, 2021 at 14:10
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    $\begingroup$ For this, you need to be really far far away from massive objects. $\endgroup$
    – AJN
    Dec 28, 2021 at 16:55
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    $\begingroup$ As gravitational influence goes out to infinity, it is not possible to find a space where there is nothing to orbit. $\endgroup$
    – Mike H
    Dec 28, 2021 at 19:44
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    $\begingroup$ Without moving relative to what? The Moon moves with an insane speed relative to Earth, the Earth and the Moon together move at an even more insane speed relative to the Sun, the Sun, Earth, and the Moon together move relative to our arm of the galaxy, our arm of the galaxy moves relative to the center of the galaxy, the galaxy as a whole moves relative to the galaxy cluster, the cluster moves relative to the supercluster, the supercluster moves relative to the other superclusters, and they all move relative to each other. $\endgroup$ Dec 28, 2021 at 20:11

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If by "not orbiting" you mean we're going to crash into the nearest planet if nothing is done, which sounds like a perfectly valid interpretation to me, it's certainly possible to "stay in space" (avoid crashing).

One option would be to keep running engines to counteract gravity, but sadly rocket engines aren't efficient enough to prevent the fuel from running out very fast.

A type of propulsion not requiring propellant is solar sails, and when used in this fashion, hoovering in an otherwise impossible location, they are known as statites

Alternatively, using a support structure to stay in space is plausible as well. Having the top floor of a skyscraper (spacescraper?) outside the atmosphere would work, but isn't practical on Earth at least. Tether support is perhaps more promising, and you don't have to go full space elevator for something that accomplishes the task. Many skyhook schemes have vehicles travelling at suborbital velocities, but staying in space due to supporting cables.

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  • $\begingroup$ Ion engine powered statite in solar non-orbit is viable (providing you get the 30km/s delta-V to get it there in the first place). It will run out sooner or later, but the amount of thrust needed vs the fuel usage of good ion engines means it could be weeks or months of "floating" before it starts "falling" into the Sun. $\endgroup$
    – SF.
    Jan 13, 2022 at 11:21
  • $\begingroup$ to crash into the nearest planet isn't it a special kind of orbit? $\endgroup$
    – Uwe
    Jan 13, 2022 at 12:05
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The question isn't valid from a physics standpoint because velocity anywhere is relative. You can escape the gravitational influence of a body by reaching an escape velocity (actually speed) relative to that body, defined as $\sqrt{\frac{2GM}{d}}$. But you will always be in motion relative to some body, so "stay in space" isn't a legitimate concept. For example, if you were to escape an orbit of Earth, you would still be orbiting the Sun. If you then escape the gravitational influence of the Sun, you would still be orbiting the center of the Milky Way galaxy, etc.

Regarding your question in the comments about staying in between the Earth and Moon without moving - the Moon is in orbit around the Earth. So to seemingly remain in place relative to those two, you would need to be orbiting the Earth as well.

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