Molniya Orbit

 

Molniya Orbit
Credits - Alaska Aerospace Development Corp.

A Molniya orbit, often referred to as a highly elliptical orbit (or HEO) is an egg-shaped orbit inclined approximately 60 degrees to the equator with a high apogee over the northern hemisphere and a low perigee over the southern hemisphere. Molniya, which means "lightning" in Russian, was the name of the first Russian communications satellites to use it. In this type of orbit, the satellite makes one revolution around the Earth approximately every 12 hours. The satellite swings low and fast over the southern hemisphere and then slows as it rises toward its apogee in the northern hemisphere, making it appear to "hover" in the sky over northern territories for long periods of time. This type of orbit is suitable for communications services in the high-latitude areas over Russia and is also used by U.S. intelligence satellites that focus on spying on Russia and Russian missile warning satellites that are observing U.S. ICBM silos.