Space Elevator - Geosynchronous Orbit(GEO)

  The space elevator is a concept that moves from the ground to the space station by means of an elevator. The concept is easy to understand, but it is not easy to imagine how it will work.

  The first thing to consider is that the Earth is rotating. Currently, artificial satellites floating outside the Earth orbit the Earth using their own power to maintain their distance from the Earth. Therefore, the reality is that if the power goes down, the lifespan of the artificial satellite will also end. In any case, since satellites are not connected to the Earth, they have possibility to flexibly respond to various situations. However, since the space elevator is connected to the Earth by cables, how can it maintain the same distance and altitude as the rotating Earth? The answer can be found by understanding the Geosynchronous Orbit.

  Geosynchronous Orbit or Geosynchronous Equatorial Orbit (GEO) refers to an orbit that always appears stationary when viewed from the ground because the period of the satellites orbiting the earth is the same as the period of rotation of the earth. When viewed from a satellite, it also means that you are always looking at the same location on the ground. This is the position where the centrifugal force of the Earth's gravity and the centrifugal force of the orbiting satellite becomes zero while being equal to the rotation angular velocity of the Earth.

  Geostationary orbit is 35,786 km above the ground(equator). If you compare it with the Earth's radius of 6,371 km, you can get an idea of ​​how far that distance is. The orbital speed of the geostationary orbit satellite is 11,069 km/h(6,878 mi/h), so it must move very quickly.

  Therefore, a space dock(space port, space station) in geostationary orbit can be maintained at the same altitude with a fixed position on the earth (elevator platform) and a cable connection.

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The original text of this article was written in Korean(click). It is provided in English using Google Translate. If anyone corrects the English and sends it to us, we will reflect it.

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