Radar calibration objects (but also cover for other classified subsatellites).

Typical orbit: 786 km circular orbit, 88.1 deg inclination. Associated Launch Vehicle: Atlas F, Thor Able-Star, Thor Agena D, Thor Burner.

• 1964 October 6 - Calsphere 1 - Launch Site: Vandenberg. Launch Vehicle: Thor Able-Star. Mass: 1.00 kg (2.20 lb). Perigee: 997 km (619 mi). Apogee: 1,034 km (642 mi). Inclination: 90.10 deg. Period: 105.50 min.

  Space craft engaged in investigation of spaceflight techniques and technology (US Cat A).

• 1964 October 6 - Calsphere 2 - Launch Site: Vandenberg. Launch Vehicle: Thor Able-Star. Mass: 10 kg (22 lb). Perigee: 1,049 km (651 mi). Apogee: 1,078 km (669 mi). Inclination: 90.20 deg. Period: 106.50 min.

  Space craft engaged in investigation of spaceflight techniques and technology (US Cat A).

• 1965 August 13 - Calsphere 4A - Launch Site: Vandenberg. Launch Vehicle: Thor Able-Star. Mass: 2.00 kg (4.40 lb). Perigee: 1,077 km (669 mi). Apogee: 1,179 km (732 mi). Inclination: 90.10 deg. Period: 107.90 min.

  Surveillance Calibration; white 14 inch dia. sphere.

• 1967 May 31 - Calsphere 4 - Launch Site: Vandenberg. Launch Vehicle: Thor Agena D. Perigee: 815 km (506 mi). Apogee: 834 km (518 mi). Inclination: 69.90 deg. Period: 101.40 min.

  Space craft engaged in investigation of spaceflight techniques and technology (US Cat A).

• 1967 May 31 - Calsphere 3 - Launch Site: Vandenberg. Launch Vehicle: Thor Agena D. Mass: 38 kg (83 lb). Perigee: 900 km (550 mi). Apogee: 906 km (562 mi). Inclination: 70.00 deg. Period: 103.10 min.

  Surveillance Calibration. Space craft engaged in investigation of spaceflight techniques and technology (US Cat A).

• 1968 August 16 - AVL-802 Rigid Sphere - Launch Site: Vandenberg. Launch Vehicle: Atlas F. FAILURE: Failure.

• 1968 August 16 - AVL-802 Grid Sphere 7-2 - Launch Site: Vandenberg. Launch Vehicle: Atlas F. FAILURE: Failure.

• 1968 August 16 - AVL-802 Mylar Sphere - Launch Site: Vandenberg. Launch Vehicle: Atlas F. FAILURE: Failure.

• 1971 February 17 - Calsphere 3A - Launch Site: Vandenberg. Launch Vehicle: Thor Burner. Mass: 1.00 kg (2.20 lb). Perigee: 509 km (316 mi). Apogee: 531 km (329 mi). Inclination: 98.40 deg. Period: 95.00 min.

  Radar calibarion sphere. Space craft engaged in investigation of spaceflight techniques and technology (US Cat A).

• 1971 February 17 - Calsphere 4 - Launch Site: Vandenberg. Launch Vehicle: Thor Burner. Mass: 1.00 kg (2.20 lb). Perigee: 486 km (301 mi). Apogee: 502 km (311 mi). Inclination: 98.40 deg. Period: 94.50 min.

  Radar calibarion sphere. Space craft engaged in investigation of spaceflight techniques and technology (US Cat A).

• 1971 February 17 - Calsphere 5 - Launch Site: Vandenberg. Launch Vehicle: Thor Burner. Mass: 1.00 kg (2.20 lb). Perigee: 340 km (210 mi). Apogee: 360 km (220 mi). Inclination: 98.20 deg. Period: 91.50 min.

  Radar calibarion sphere. Space craft engaged in investigation of spaceflight techniques and technology (US Cat A).

• 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.

• 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, 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.