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High Earth orbit 
Summary
To-scale diagram of low, medium and high Earth orbits
A high Earth orbit is a geocentric orbit with an altitude entirely above that of a geosynchronous orbit (35,786 kilometres (22,236 mi)).[1] 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[2][3] | 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° |
References
- ^ "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