# High Earth orbit

Comparison of GPS, GLONASS, Galileo and Compass (medium earth orbit) satellite navigation system orbits with the International Space Station, Hubble Space Telescope and Iridium constellation orbits, Geostationary Earth Orbit, and the nominal size of the Earth.[a] The Moon's orbit is around 9 times larger (in radius and length) than geostationary orbit.[b]

A high Earth orbit is a geocentric orbit with an altitude above that of a geosynchronous orbit (35,786 kilometres (22,236 mi)).[1]

To-scale diagram of low, medium and high earth orbits

## 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

1. ^ Orbital periods and speeds are calculated using the relations 4π²R³ = T²GM and V²R = GM, where R = radius of orbit in metres, T = orbital period in seconds, V = orbital speed in m/s, G = gravitational constant ≈ 6.673×10−11 Nm²/kg², M = mass of Earth ≈ 5.98×1024 kg.
2. ^ Approximately 8.6 times when the moon is nearest (363 104 km ÷ 42 164 km) to 9.6 times when the moon is farthest (405 696 km ÷ 42 164 km).