The Luch or Altair satellites were the first generation of Soviet and later Russian data relay satellites. These satellites provided communications service to the Mir space station, Buran space shuttle, Soyuz-TM spacecraft, military satellites and the TsUPK ground control center.

Luch was built by NPO-PM based on their KAUR-4 3-axis stabilized geostationary satellite platform, which featured plasma station-keeping engines and hydrazine monopropellant orientation engines. The 2400 kg satellites featured three large antennas and numerous, small helical antennas permitted data relays in the 15/14, 15/11, and 0.9/0.7 GHz bands. Each satellite was equipped with three Arion transponders by NPO Radiopribor for data transmission. The design life was five years.

Beginning in 1995, four satellites were launched. The first three were operated under the designations Cosmos 1700, Cosmos 1897 and Cosmos 2054. The Kosmos designator was dropped for the fourth satellite, which was simply refered as Luch 1. A fifth satellite was never launched.