Test satellite.

Typical orbit: 486 km x 40038 km at 64 degrees inclination. Mass: 23 kg (50 lb). Associated Launch Vehicle: Molniya 8K78M.

• 1972 April 4 - SRET 1 - Launch Site: Plesetsk. Launch Vehicle: Molniya 8K78M. Mass: 15 kg (33 lb). Perigee: 458 km (284 mi). Apogee: 39,250 km (24,380 mi). Inclination: 65.60 deg. Period: 704.70 min.

  Test satellite. Investigation of the upper atmosphere and outer space.

• 1975 June 5 - SRET 2 - Launch Site: Plesetsk. Launch Vehicle: Molniya 8K78M. Mass: 30 kg (66 lb). Perigee: 513 km (318 mi). Apogee: 40,825 km (25,367 mi). Inclination: 62.80 deg. Period: 737.80 min.

  SRET 2 technological research and study satellite. Launched from Soviet Union with a Soviet launch vehicle with the Molniya satellite. Mass 30 kg. Study of the behaviour of a passive cryogenic radiation system, study of the aging of thermal casings and pl astic films.

• USAF Satellite Database, USAF Institute of Technology, 1995. Accessed at: ftp://archive.afit.af.mil/pub/space/.

• McDowell, Jonathan, Jonathan's Space Home Page, Harvard University, 1997-present. Jonathan McDowell's complete on-line listing of all objects orbited and over 20,000 rocket launches Accessed at: http://www.planet4589.org/jsr.html.

• McDowell, Jonathan, Launch Log, October 1998. Jonathan McDowell's complete on-line listing of all objects orbited since Sputnik. Accessed at: http://hea-www.harvard.edu/~jcm/space/log/launch.html.

• JPL Mission and Spacecraft Library, Jet Propulsion Laboratory, 1997. Accessed at: http://msl.jpl.nasa.gov/home.html.

• Krebs, Gunter, Gunter's Space Page, University of Frankfurt, 1996. Accessed at: http://www.skyrocket.de/space.