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The exact height of a satellite in a Molniya orbit varies between missions, but a typical orbit will have a perigee altitude of approximately 600 kilometres (370 mi) and an apogee altitude of 39,700 kilometres (24,700 mi), for a semi-major axis of 26,600 kilometres (16,500 mi).
The Molniya (Russian: ... the perigee needed to be far enough above the atmosphere to avoid drag, and the orbital period needed to be approximately half a sidereal ...
Molniya orbit: A semi-synchronous variation of a Tundra orbit. For Earth this means an orbital period of just under 12 hours. Such a satellite spends most of its time over two designated areas of the planet. An inclination of 63.4° is normally used to keep the perigee shift small. [15]
A highly elliptical orbit (HEO) is an elliptic orbit with high eccentricity, usually referring to one around Earth.Examples of inclined HEO orbits include Molniya orbits, named after the Molniya Soviet communication satellites which used them, and Tundra orbits.
The Soviet Union launched its first communications satellite on 23 April 1965 as part of the Molniya program. [26] This program was also unique at the time for its use of what then became known as the Molniya orbit, which describes a highly elliptical orbit, with two high apogees daily over the northern hemisphere. This orbit provides a long ...
Molniya orbit A highly elliptical orbit with inclination of 63.4° and orbital period of ½ of a sidereal day (roughly 12 hours). Such a satellite spends most of its time over a designated area of the Earth. Tundra orbit A highly elliptical orbit with inclination of 63.4° and orbital period of one sidereal day (roughly 24 hours). Such a ...
A wide variety of sources [4] [5] [6] define LEO in terms of altitude.The altitude of an object in an elliptic orbit can vary significantly along the orbit. Even for circular orbits, the altitude above ground can vary by as much as 30 km (19 mi) (especially for polar orbits) due to the oblateness of Earth's spheroid figure and local topography.
Clickable image, highlighting medium altitude orbits around Earth, [a] from Low Earth to the lowest High Earth orbit (geostationary orbit and its graveyard orbit, at one ninth of the Moon's orbital distance), [b] with the Van Allen radiation belts and the Earth to scale To-scale diagram of low, medium, and high Earth orbits Space of Medium Earth orbits (MEO) as pink area, with Earth and the ...