I have read somewhere that to-be astronauts are trained on Earth to be deft enough when they are in space which has zero gravity. How do we create a zero gravity situation on Earth? On Earth, even if you are in a vacuum, you still experience the force of gravity, so exactly how do we engineer such a situation which actually defies gravity on Earth itself?

  • $\begingroup$ For researching the effects of micro-gravity (0g) or partial-gravity (between 0g and 1g) also a Sounding Rocket, a Clinostat or a Random Positioning Machine can be used. $\endgroup$
    – Matthijs
    Commented Oct 24, 2017 at 8:59
  • $\begingroup$ Technically, even in orbit you experience gravity. It just appears that you don't. $\endgroup$
    – Innovine
    Commented Jun 5, 2022 at 10:15

1 Answer 1


There are two methods which are used:

  1. Aircraft can fly on a trajectory that will simulate zero gravity for a few seconds, usually around 30. This is used for most short term zero gravity tests. It is commonly known as the "vomit comet", especially the earlier versions.
  2. Underwater testing can be done, in a neutral buoyancy lab. Basically, you make it so you weigh as much as the water you displace does, making it so you "float" in zero gravity. If you pushed away from something, you would continue to move (Although being in water, you have drag and swimming that could move you as well)

Both are approximations, but they do work well enough to do something at least.

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    $\begingroup$ More information about the "zero gravity" aircraft is available on Wikipedia. This technique was also used for filming zero-gravity scenes in space movies (e.g. Apollo 13). $\endgroup$
    – Lightsider
    Commented Oct 29, 2015 at 8:43
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    $\begingroup$ It's also known as the vomit comet. $\endgroup$
    – GdD
    Commented Oct 29, 2015 at 8:55
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    $\begingroup$ For unmanned experiments, a drop tower can also be used, if the experiment can be made to survive the drop. $\endgroup$
    – Hobbes
    Commented Oct 29, 2015 at 15:57
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    $\begingroup$ For frogstronauts, magnetic levitation can also be used. Because the diamagnetic lifting force is distributed throughout the body, it feels like it's in freefall. $\endgroup$ Commented Oct 29, 2015 at 17:08
  • 1
    $\begingroup$ en.wikipedia.org/wiki/Zero_Gravity_Research_Facility $\endgroup$ Commented Nov 2, 2015 at 11:54

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