Data Set Overview
  =================
    The Lunar Prospector attitude data set consists of values for the
    spacecraft spin rate and spin axis orientation (attitude) as a
    function of time.  These values are determined from spacecraft
    attitude data (sun and limb crossing sensors) and ephemeris data.
    The details as to how attitude and spin rate are determined are
    given in the Project's Ground Software User's Guide and Programmer's
    Guide [JACOBSEN1998].
 
    Spacecraft orientations are given as right ascension and declination
    of the spacecraft spin axis in the Mean-of-J2000 Ecliptic reference
    frame.  The attitude data set consists of a single, cumulative file
    for the entire mission.  Records were added to this file following
    each significant change in either the spin rate or spin axis
    orientation.
 
    The spacecraft spin rates and attitudes in this data set are orbit
    averages.  The instantaneous spin rate can be determined from the
    sun pulse data set.  The instantaneous spin rate varied as the
    spacecraft passes into and out of the Moon's shadow due to thermal
    effects and after each spacecraft maneuver.  Generally, an attitude
    record is included for times immediately before and after each
    maneuver.
 
 
  Science Objectives
  ==================
    The Lunar Prospector science objectives relevant to this data set
    are to map the Moon's surface composition and its magnetic field, and
    to determine the frequency and location of gas release events.  A
    special emphasis of the science objectives is to search for polar
    water ice deposits [BINDERETAL1998].  The spacecraft attitude and spin
    rate data are used to determine the spacecraft orientation at the time
    science data were acquired.

Confidence Level Overview
  =========================
    Spin rate is given as the orbit average rate of spin.  During eclipse,
    the instantaneous spin rate may differ from the mean spin rate by up
    to 0.01 revolutions per minute as the spacecraft passed into and out
    of the Moon's shadow.
 
    The uncertainty in spacecraft attitude (right ascension and
    declination) is estimated to be about one degree of arc.  The
    spacecraft attitude generally varied by less than one degree per day,
    except during maneuvers.  No attempt was made to determine the
    instantaneous spacecraft attitude during a maneuver.  Following a
    maneuver, the spacecraft nutated for 6 to 8 hours.
 
 
  Data Coverage and Quality
  =========================
    Attitude and spin rate determinations exist for the entire Lunar
    Prospector Primary and Extended Missions.
 
    The Earth-Moon Limb Sensor was turned off toward the end of the
    Primary Mission and into the Extended Mission to extend the spacecraft
    battery life.  During this time attitude determinations were based
    only on Sun Sensor data.