Highly Elliptical Orbit (HEO)
High-latitude communications and some scientific missions, using a high apogee that lingers over one hemisphere.
Overview
An elongated orbit with a low perigee and a very high apogee (as in the Molniya and Tundra orbits). The satellite moves slowly near apogee, dwelling for hours over high latitudes that geostationary orbit cannot serve.
Typical uses
High-latitude communications and some scientific missions, using a high apogee that lingers over one hemisphere.
Satellites in this orbit
1 satellite and constellations modelled in this orbit.
- MolniyaRetired
A long-running series of Soviet communications satellites that gave their name to the Molniya orbit — a highly elliptical orbit whose slow apogee high over the northern latitudes provided the coverage that geostationary satellites could not reach at high latitudes.
OperatorSoviet space programOrbitMolniya (HEO)Launched1965
Sources
The primary and reference sources this topic draws on.
- NASANational Aeronautics and Space Administration
Mission data, planetary science, space telescopes, and public-domain imagery.
Most NASA-produced imagery is in the public domain; individual items are checked for usage terms before publication.
- ESAEuropean Space Agency
European missions, observatories, and space science imagery.