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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).
In the early 1960s, when Europe and America were establishing geostationary communication satellites, the Russians found these orbits unsuitable. [6] They were limited in the amount of rocket power available and it is extremely energy intensive to both launch a satellite to 40,000 km, and change its inclination to be over the equator, especially when launched from Russia.
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.
This comparison of retired orbital launch systems lists the attributes of all retired individual rocket ... NPO Molniya. 58.8 m 30,000 [18 ... (standard) 17,110
For Earth orbiting satellites below the height of about 800 km, the atmospheric drag is the major orbit perturbing force out of all non-gravitational forces. [11] Above 800 km, solar radiation pressure causes the largest orbital perturbations. [12]
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 ...
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.
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 ...