Atmospheric density studies.

Typical orbit: 235 x 758 km, 9.9 deg inclinaton. Associated Launch Vehicle: Scout B, Scout D, Scout G, Scout X-4.

• 1964 December 15 - San Marco 1 - Launch Site: Wallops Island. Launch Vehicle: Scout X-4. Mass: 254 kg (559 lb). Perigee: 200 km (120 mi). Apogee: 842 km (523 mi). Inclination: 37.80 deg. Period: 95.10 min.

  Atmospheric density studies. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

• 1967 April 26 - San Marco 2 - Launch Site: San Marco. Launch Vehicle: Scout B. Mass: 129 kg (284 lb). Perigee: 219 km (136 mi). Apogee: 741 km (460 mi). Inclination: 2.90 deg. Period: 94.20 min.

  Atmospheric density data. Scientific satellite launched from a mobile range off Formosa Bay (Kenya).

• 1971 April 24 - San Marco 3 - Launch Site: San Marco. Launch Vehicle: Scout B. Mass: 164 kg (361 lb). Perigee: 222 km (137 mi). Apogee: 707 km (439 mi). Inclination: 3.20 deg. Period: 93.80 min.

  Atmospheric research. Spacecraft engaged in research and exploration of the upper atmosphere or outer space (US Cat B).

• 1974 February 18 - San Marco 4 - Launch Site: San Marco. Launch Vehicle: Scout D. Mass: 164 kg (361 lb). Perigee: 270 km (160 mi). Apogee: 875 km (543 mi). Inclination: 2.90 deg. Period: 96.10 min.

  Measurement of density, temperature, composition of atmosphere. Launch time 10:05:28.5 GMT. Anticipated life: 3 years.

• 1988 March 25 - San Marco D/L - Launch Site: San Marco. Launch Vehicle: Scout G. Mass: 236 kg (520 lb). Perigee: 268 km (166 mi). Apogee: 625 km (388 mi). Inclination: 3.00 deg. Period: 93.50 min.

  Upper atmosphere studies; US, France, Italy participation.

• 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.