Signals intelligence satellite; possibly some kind of imaging also done. On-board propulsion boosts spacecraft to 800 km operating orbit.

Typical orbit: 4, 6. Mass: 1,700 kg (3,700 lb). Associated Launch Vehicle: Titan 2.

• 1988 September 5 - USA 32 - Launch Site: Vandenberg. Launch Vehicle: Titan 2. Mass: 1,700 kg (3,700 lb). Perigee: 185 km (114 mi). Apogee: 292 km (181 mi). Inclination: 85.00 deg. Period: 89.30 min.

  New class of signals intelligence satellite; possibly some kind of imaging also done. On-board propulsion boosts spacecraft to 800 km operating orbit.

• 1989 September 6 - USA 45 - Launch Site: Vandenberg. Launch Vehicle: Titan 2. Mass: 1,700 kg (3,700 lb).

  Signals intelligence. Reentered from initial parking orbit of 200 km after failure of on-board boost motor.

• 1992 April 25 - USA 81 - Launch Site: Vandenberg. Launch Vehicle: Titan 2. Mass: 1,700 kg (3,700 lb). Perigee: 145 km (90 mi). Apogee: 175 km (108 mi). Inclination: 84.90 deg. Period: 89.30 min.

  Signals intelligence satellite; possibly some kind of imaging also done. On-board propulsion boosts spacecraft to 800 km operating orbit.

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

• McDowell, Jonathon, Quest, "US Reconnaissance Satellite Programs Part 2", 1995, Volume 4, Issue 4, page 49.

• Lockheed Martin Coporation, Atlas Family Fact Sheets, September 1998.. Accessed at: http://www.lmco.com/ILS/txtmain/ils_lsysinfo.htm.

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

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

• 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.