High Earth orbit

High Earth orbit

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 twenty-four 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.

Example of satellite 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 6,519.6 min 37.8°

Notes

References

  1. ^ "Definitions of geocentric orbits from the Goddard Space Flight Center". User support guide: platforms. NASA Goddard Space Flight Center. Retrieved 2012-07-08. 
  2. ^ Vela at Encyclopedia Astronautica
  3. ^ Trajectory Details for Vela 1A from the National Space Science Data Center