Mission Overview
  ================

  The Midcourse Space Experiment (MSX) mission began with the launch of
  the spacecraft on April 24, 1996 into a ~900 km polar orbit for a
  nominal 5 year mission.  The MSX mission was divided into three
  phases.

  Phase 1, which ended on February 26, 1997 with the depletion of the
  cryogen, was devoted almost exclusively to observations with the
  infrared telescope, SPIRIT III.

  Phase 2, lasting from cryogen depletion through September 1997,
  emphasized astronomy and atmospheric measurements with the UVISI
  (Ultraviolet/Visible Imaging and Spectrographic Imaging) sensors.

  Phase 3 began in October 1997 when the SBV (Space Based Visible)
  Camera became a contributing sensor to the US Space Surveillance
  Network.

  Instruments on MSX included an infrared imaging camera (SPIRIT III),
  ultraviolet/visible imaging and spectrographic imaging sensors
  (UVISI), a visible-wavelength camera (SBV), and a suite of
  contamination detectors.

  Further information about the MSX spacecraft and instruments may be
  found in [MILLETAL1994]:

  Mill, J.D., R.R. O'Niel, S. Price, G.J. Romick, O.M. Uy, and 5 other
  authors, Midcourse Space Experiment:  Introduction to the spacecraft,
  instruments, and scientific objectives, Journal of Spacecraft and
  Rockets 31, 900-907, 1994.

Mission Objectives Overview
  ===========================
    The principal goal of MSX was to collect phenomenology data
    in support of ballistic missile defense objectives.  Additional
    objectives were to collect data in support of a variety of civilian
    science objectives in earth and atmospheric remote sensing and
    astronomy.  A full set of experiments mapped the galactic plane,
    the IRAS (Infrared Astronomical Satellite) gaps, the zodiacal
    background, confused regions away from the galactic plane, deep
    surveys of selected fields at high galactic latitudes, large
    galaxies, asteroids, and comets.