四、通信卫星 1.静止卫星的运动轨道先简单说明静止卫星的运动轨道问题。卫星运动是服从万有引力定律的。如果把卫星和地球都看成是质量集中于中心的两质点,则对地静止的卫星必须满足:卫星在赤道平面内由西向东转动,即卫星转动方向与地球的自转方向一致;卫星的轨道为圆轨道,有一定的高度,使卫星环绕地球的公转周期与地球的自转周期相同。按上述原理,当卫星在赤道平面内围绕地球作圆周运动时,卫星的重力应等于它的向心力,有 Fourth, communications satellites 1. Geostationary satellite orbit The first brief description of geostationary orbit motion problems. Satellite movement obeys the law of universal gravitation. If both satellites and the earth are considered as two qualitatively concentrated centers, the geostationary satellites must satisfy: the satellite rotates from west to east in the equatorial plane, that is, the direction of rotation of the satellite coincides with the direction of rotation of the Earth; the orbit of the satellite For a circular orbit, there is a certain height, so that the orbit around the Earth’s revolution period is the same as the earth’s rotation period. According to the above principle, when the satellite moves circularly around the Earth in the equatorial plane, the gravity of the satellite should be equal to its centripetal force, and there