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.