In the aerospace context, weightlessness, also known as microgravity, refers to the state of near-zero gravity experienced in space, where the gravitational force is much weaker than on the surface of the Earth.
It is the condition that results when an object is in free fall under the influence of gravity. This can occur in space, far from any celestial body, or when an object is in orbit around a celestial body, such as the Earth.
Examples of weightlessness in the aerospace context include:
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Spacecraft in orbit: A spacecraft in orbit around a celestial body, such as the International Space Station, experiences weightlessness because it is in a state of free fall around the Earth. This allows astronauts to float freely inside the spacecraft and conduct scientific experiments without the interference of gravity.
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Free-fall parabolic flights: Some aircrafts can perform parabolic maneuvers to simulate weightlessness by flying in a parabolic trajectory that allows occupants to experience short periods of weightlessness. This is used for training astronauts and for scientific research.
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Lunar and planetary surface activities: When astronauts are on the surface of the Moon or other celestial bodies, they are in a state of microgravity because the gravitational force is much weaker than on the Earth. This can make it difficult to move and perform tasks, but also allows for unique scientific opportunities.
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High altitude jumps: Some skydivers and BASE jumpers can experience weightlessness during free fall by jumping from very high altitudes, such as from the edge of space.
In summary, weightlessness or microgravity in the aerospace context refers to the state of near-zero gravity experienced in space, it is the condition that results when an object is in free fall under the influence of gravity, examples include spacecraft in orbit, free-fall parabolic flights, lunar and planetary surface activities, and high altitude jumps.