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