Luch data-relay satellite

The Luch ("beam") series of satellites was designed to provide communications with other spacecraft when they fly beyond the range of ground stations. Often referred to as a relay satellite, Luch would be placed in the geostationary orbit 36,000 kilometers over the Equator, where they would appear "hanging" over a single point of the Earth surface, like most regular communications satellites. Three spacecraft evenly spread over this orbit would be enough to provide a global coverage over the Earth surface and enable most satellites in lower orbits to always stay in contact with ground control. The Luch spacecraft was a Russian equivalent of the American Tracking and Data Relay Satellite, TDRS. Latest satellites in both networks were designed to receive and relay large amount of data from the International Space Station, ISS, among other spacecraft equipped with compatible transmitters and antennas.


Origin of the program

The first generation of Luch satellites designed to be launched by the Proton rocket was developed in the USSR with the primary goal of supporting such key Soviet projects in manned space flight as the Mir space station and Buran winged orbiter. In fact, development of the first Soviet data-relay system, then known as Global Space Command and Relay System, GKKRS, was approved on Feb. 17, 1976, by the same government decree No. 132-51, which gave go ahead to the Buran project. Along with helping communications with the Buran orbiter, the GKKRS spacecraft was expected to transmit strategically important information from reconnaissance satellites. The document set the first test launch of the GKKRS satellite for 1981. (208)

The military version of the relay satellite, known as Geyzer, flew on May 18, 1982, under "cover" name Kosmos-1366, followed in the same year by the beginning of a full-scale development of the Luch satellite.

Three satellites of the Luch constellation were to be deployed over the Atlantic (16 degrees West), Indian Ocean (95 East) and Pacific (160 West). (536) Each spacecraft was equipped with three deployable antennas with diameters of 1.6, 3 and 4.5 meters. To build these antennas, NPO PM needed unique metallic mesh developed at Paton Material Science Institute in Kiev. However for large-scale production of the material, USSR had to acquire highly specialized machinery from another side of the Iron Curtain, in West Germany. (389)

However the first Luch satellite lifted off only on Oct. 25, 1985, in anticipation of the first piece of the Mir space station, which was equipped with a special antenna to communicate via Luch. Follow-on Luch satellites supported unmanned military satellites and the Buran orbiter.

On Oct. 12, 1995, the first and only second-generation Luch satellite (Luch-2), which was in development since 1993, was launched and survived in orbit until 1998.

In the post-Soviet turmoil, the funding for the program disappeared, leaving Mir and, later, the Russian segment of the ISS without communications beyond 2.5-hour-a-day periods of the flight directly over Russian ground stations. As the assembly of the station intensified, often involving spacewalking cosmonauts, Russia had to acquire services of the US TDRSS network.

Known specifications of the original Luch satellite:

Total launch mass
2,400 kilograms
Power supply
1,800 Watts
Earth pointing accuracy
0.1 degrees
Station keeping accuracy
0.5 degrees
Operational lifespan
5 years
Dimensions (in deployed position)
8.5 by 11.0 by 16.0 meters
Number of transponders
NPO PM of Zheleznogorsk
Launch vehicle



Page author: Anatoly Zak; Last update: March 8, 2024

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Artist depiction of the Luch satellite. Credit: ISS Reshetnev



A Luch satellite during assembly and testing. Credit: ISS Reshetnev



A demo version of the original Luch satellite. Copyright © 2000 Anatoly Zak



The main body of the original Luch satellite. Copyright © 2000 Anatoly Zak


One characteristic feature of relay satellites is very large communications antennas. Copyright © 2000 Anatoly Zak