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| | CelesTrak: "More on the Geostationary Orbit" |
 | | For the satellite to be geostationary, of course, its latitude must be zero and its altitude must be 35,786 kilometers (for this development, we will assume a true geostationary orbit and a spherical earth). |
 | | In both cases, it should be noted that the rotation axis of the satellite is perpendicular to the satellite's orbital plane—which for geostationary orbits is the equatorial plane. |
 | | As the earth goes around its orbit, its distance from the sun changes from a minimum of 0.983 astronomical units (AUs—the mean distance from the earth to the sun is approximately 1 AU or 149,597,870 km) to a maximum of 1.067 AU—a difference of 12,518,000 km. |
| celestrak.com /columns/v04n09 (1680 words) |
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