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Project Overview

Introduction This spacecraft is part of a continuing series of classified spacecraft. The three spacecraft USA 39 (89-046A), USA 65 (90-095A), and USA 75 (91-080B) replace an earlier constellation of geosynchronous orbit spacecraft. These three were positioned at longitudes of approximately 195, 8, and 72 degrees, respectively, as of February 20, 1992. Each spacecraft carries two instruments whose data are available for magnetospheric research: the Magnetospheric Plasma Analyzer (MPA) and the Synchronous Orbit Particle Analyzer (SOPA). The article by McComas et al., ``Magnetospheric plasma analyzer: Initial three-spacecraft observations from geosynchronous orbit,'' (J. Geophys. Res., 98, No. A8, p. 13453, 1993) gives more information. It also declares: ``Recently, the MPA and SOPA data sets have become part of the International Solar Terrestrial Physics (ISTP) program with the inclusion of key parameter data in the ISTP Central Data Handling Facility (CDHF). These data should provide a valuable adjunct to ISTP science, particularly in light of the lack of a dedicated `Equator' spacecraft, in addition to providing new information about the geosynchronous environment in their own right.''

Project Scientist This forces spacing between the columns Donald Fairfield
Phone: (301) 286-7472
e-mail: u2dhf@lepdhf.gsfc.nasa.gov

Instrument Descriptions MPA

For more information, see:

  • The MPA Homepage
  • The SOPA Homepage

  • Comments/Questions/Suggestions: Natalie Jaquith
    Official NASA Contact: Barbara Giles
    / NASA Home / Goddard Space Flight Center Home /

    Above is background material for archival reference only.

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