IMEWS was the first generation DSP satellite. Spacecraft: Spacecraft spin slowly (6 rpm) about the nadir axis to permit scanning of the Earth by the detector system. Body mounted and deployable panels provide 400W. Payload: Payload information is not available.

Design Life: 3 years. Typical orbit: Geosynchronous (F1 in lower than planned orbit). Mass: 820 kg (1,800 lb). Associated Launch Vehicle: Titan 3C.

• 1970 November 6 - IMEWS 1 - Launch Site: Cape Canaveral. Launch Vehicle: Titan 3C. FAILURE: Partial Failure. Mass: 820 kg (1,800 lb). Perigee: 25,840 km (16,050 mi). Apogee: 36,128 km (22,448 mi). Inclination: 16.40 deg. Period: 1,197.90 min.

  First generation DSP; incorrect orbit. Exhausted fuel before could be put into operation.

• 1971 May 5 - IMEWS 2 - Launch Site: Cape Canaveral. Launch Vehicle: Titan 3C. Mass: 820 kg (1,800 lb). Perigee: 36,156 km (22,466 mi). Apogee: 36,527 km (22,696 mi). Inclination: 10.50 deg. Period: 1,464.60 min.

  First generation DSP. First operational satellite. Positioned over the Indian Ocean 75 deg E in 1979-1982 Last known longitude (0 January 1900) drifting at per day.

• 1972 March 1 - IMEWS 3 - Launch Site: Cape Canaveral. Launch Vehicle: Titan 3C. Mass: 820 kg (1,800 lb). Perigee: 35,416 km (22,006 mi). Apogee: 35,962 km (22,345 mi). Inclination: 0.20 deg. Period: 1,429.90 min.

  First generation DSP. Positioned over the Pacific Ocean 165 deg E in 1979-1980. Last known longitude (0 January 1900) drifting at per day.

• 1973 June 12 - IMEWS 4 - Launch Site: Cape Canaveral. Launch Vehicle: Titan 3C. Mass: 820 kg (1,800 lb). Perigee: 35,777 km (22,230 mi). Apogee: 35,786 km (22,236 mi). Inclination: 0.30 deg. Period: 1,435.90 min.

  Positioned in geosynchronous orbit over the Indian Ocean at 75E? 1973-?; over the Americas at 105 deg W in 1979-1980 Last known longitude (0 January 1900) drifting at per day.

• 1975 December 14 - IMEWS 5 - Launch Site: Cape Canaveral. Launch Vehicle: Titan 3C. Mass: 820 kg (1,800 lb). Perigee: 35,671 km (22,164 mi). Apogee: 35,785 km (22,235 mi). Inclination: 3.00 deg. Period: 1,436.00 min.

  Last known longitude (0 January 1900) drifting at per day.

• 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.

• Vis, Bert, Spaceflight, "Shuttle Weather Watch", 1996, Volume 38, page 170. Details on USAF weather astronauts

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

• 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.