High Earth orbit

A high Earth orbit is a geocentric orbit with an altitude entirely above that of a geosynchronous orbit (35,786 kilometres (22,236 mi)). The orbital periods of such orbits are greater than 24 hours, therefore satellites in such orbits have an apparent retrograde motion – that is, even if they are in a prograde orbit (90° > inclination ≥ 0°), their orbital velocity is lower than Earth's rotational speed, causing their ground track to move westward on Earth's surface. A high Earth orbit is a geocentric orbit with an altitude entirely above that of a geosynchronous orbit (35,786 kilometres (22,236 mi)). The orbital periods of such orbits are greater than 24 hours, therefore satellites in such orbits have an apparent retrograde motion – that is, even if they are in a prograde orbit (90° > inclination ≥ 0°), their orbital velocity is lower than Earth's rotational speed, causing their ground track to move westward on Earth's surface.