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.
Examples of satellites in high Earth orbit
|Name||NSSDC id.||Launch date||Perigee||Apogee||Period||Inclination|
|Vela 1A||1963-039A||1963-10-17||101,925 km||116,528 km||6,519 min||37.8°|
|IBEX||2008-051A||2008-10-19||61,941 km||290,906 km||12,963 min||16.9°|
- "Definitions of geocentric orbits from the Goddard Space Flight Center". User support guide: platforms. NASA Goddard Space Flight Center. Archived from the original on 2010-05-27. Retrieved 2012-07-08.
- Vela at Encyclopedia Astronautica
- Trajectory Details for Vela 1A from the National Space Science Data Center