The U. S. military's STACKSAT mission involved the launch of three similar spacecraft, POGS, TEX and SCE.

The POGS (Polar Orbiting Geomagnetic Survey) satellite was designed to measure the Earth's magnetic field vector as a function of position for the Defense Mapping Agency. Data from the experiment would be used to improve Earth navigation systems, and was stored in an experimental Fairchild solid state recorder. TEX (Transceiver EXperiment) carried a variable power transmitter used to study ionospheric effects on RF transmissions. Data from the experiment would be used to determine minimum spacecraft transmitter power levels for transmission to ground receivers. SCE (Selective Communications Experiment) carried a variable frequency transmitter to study ionospheric effects at various RF frequencies, and was also designed to demonstrate message store and forward techniques. Six low cost ground stations were designed, built and located around the world to operate these spacecraft. The PDD Payload Deployment Device disbursed the satellites into their target orbits.

The spacecraft was gravity gradient stabilized. Body mounted solar arrays provided ~15W orbit average power. The satellite was built by Defense Systems Inc. (later CTA)

Design Life: 3 years. Typical orbit: 741 km, incl. = 90 deg. Associated Launch Vehicle: Atlas E.

• 1990 April 11 - USA 56 - Launch Site: Vandenberg. Launch Vehicle: Atlas E. Perigee: 627 km (389 mi). Apogee: 745 km (462 mi). Inclination: 89.80 deg. Period: 98.48 min.

  Polar Orbiting Geomagnetic Survey satellite designed to measure the Earth's magnetic field vector as a function of position. Data from the experiment was used to improve Earth navigation systems, and was stored in an experimental solid state recorder. Six low cost ground stations were designed, built and located around the world to operate the spacecraft flown on this mission.

• 1990 April 11 - USA 57 - Launch Site: Vandenberg. Launch Vehicle: Atlas E. Perigee: 627 km (389 mi). Apogee: 742 km (461 mi). Inclination: 89.80 deg. Period: 98.45 min.

  TEX (Transceiver EXperiment) carried a variable power transmitter used to study ionospheric effects on RF transmissions. Data from the experiment was used to determine minimum spacecraft transmitter power levels for transmission to ground receivers.

• 1990 April 11 - USA 58 - Launch Site: Vandenberg. Launch Vehicle: Atlas E. Perigee: 627 km (389 mi). Apogee: 741 km (460 mi). Inclination: 89.80 deg. Period: 98.44 min.

  SCE (Selective Communications Experiment) carried a variable frequency transmitter to study ionospheric effects at various RF frequencies, and was also designed to demonstrate message store and forward techniques.

• 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.

• 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, 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.