Satellites in high elliptical orbits are slower near apogee, so they stay longer near apogee.The apogee of the lightning orbit is 63.4 degrees north latitude in the Northern Hemisphere.The apogee is 40000 km high. When the satellite is near the apogee, the satellite has good visibility to Russia, Northern Europe, Greenland and Canada in the northern hemisphere.
In order to have continuous high coverage in the northern hemisphere, at least three man-made satellites are required in lightning orbit.[1]
purpose
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The original purpose of the lightning orbit is for the use of the lightning type (Molniya) communication satellite.In 1964, he tried to launch a man-made satellite into this orbit twice, but failed.Later, on April 23, 1965, Molniya 1-01 was successfully launched into the lightning orbit for the first time.The early Molniya-1 artificial satellite was intended to be used for long-range military communications, but because the life of the satellite itself is not long, it needs to be replaced regularly.Molniya-2 satellite is not only for military use, but also for civil broadcasting, such assatellite TVsystemOrbita。Later, it was also changed to Molniya-3 satellite.
SomeSoviet UnionOfSpy satelliteIt also operates on the adjusted lightning track, and its lightning track has been adjusted to make its apogee correspond to the United States mainland.Although inGeostationary orbitThe satellite on the can also monitor the US mainland.However, the sensing technology of the former Soviet Union would require a high contrast observation angle, and only satellites in high latitudes could be competent, such as the AKO early warning system for monitoring American missiles.Later, due to the improvement of sensing technology, such systems have been able to work with satellites in geostationary orbit.[1]
characteristic
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Many territories of the former Soviet Union (including Russia) are located in high latitudes.If man-made satellites in geostationary orbit want to send signals to these areasAngle of incidenceLarge, it takes a lot of energy to transmit signals to high latitudes, which is a big problem in man-made satellites that rely only on solar energy.Satellites in lightning orbit spend much of their time in the sky over high latitudes, so they need less energy to transmit signals.Within three hours before and after the apogeeSubstellar pointIt is located at 55.5 degrees north latitude, and the satellite elevation angle is greater than 10 degrees for all regions whose latitude is higher than 54.1 degrees north latitude on the same side of the apogee, and is greater than 5 degrees for regions whose latitude is higher than 49.2 degrees north latitude.
Another advantage is that compared toGeostationary orbitIt takes less energy to launch a satellite into lightning orbit.However, the disadvantage is that the ground station needs an antenna with adjustable direction to track the satellite, and the satellite needs to pass theVan Allen radiation beltFour times, there must be technology accumulation for manufacturing anti noise equipment.[2]
