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A Molniya orbit (Russian: Молния, IPA: [ˈmolnʲɪjə] ⓘ, "Lightning") is a type of satellite orbit designed to provide communications and remote sensing coverage over high latitudes. It is a highly elliptical orbit with an inclination of 63.4 degrees , an argument of perigee of 270 degrees, and an orbital period of approximately half a ...
They were also based on the KAUR-2 bus, launching solely from Plesetsk. Earlier models were used for civilian communications in a similar orbit, but different purpose, to the military-only Molniya-1 satellites. From 1980s they were used by the military, and by the 1990s they were operated in the same manner as the Molniya 1 satellites. [17]
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 .
If the argument of perigee is non-zero, however, the satellite will behave differently in the northern and southern hemispheres. The Molniya orbit, with an argument of perigee near −90°, is an example of such a case. In a Molniya orbit, apogee occurs at a high latitude (63°), and the orbit is highly eccentric (e = 0.72). This causes the ...
For Earth this means a period of just under 12 hours at an altitude of approximately 20,200 km (12,544.2 miles) if the orbit is circular. [16] 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 ...
There are satellites, which orbit the exosphere, between 375 miles (600 kilometers) and 6,200 miles (10,000 kilometers) ... it is steered by a process of altitude control, where it moves up or ...
The Molniya orbit is designed so that the satellite spends the great majority of its time over the far northern latitudes, during which its ground footprint moves only slightly. Its period is one half day, so that the satellite is available for operation over the targeted region for six to nine hours every second revolution.
In orbit, a spacecraft with one axis much longer than the other two will spontaneously orient so that its long axis points at the planet's center of mass. This system has the virtue of needing no active control system or expenditure of fuel. The effect is caused by a tidal force. The upper end of the vehicle feels less gravitational pull than ...