Instrument Host Overview  ========================    Lunar Prospector (LP) is a small, simple, spin-stabilized spacecraft    with minimal operational requirements [BINDERETAL1998].  Its fueled    mass is 305 kg.  The spacecraft bus is a graphite-epoxy drum that is    1.37 m in diameter and 1.28 m tall.  Power is provided by solar    cells mounted on the surface of the bus assembly, which produce an    average of 186 w.  There is also a rechargeable, 4.8 amp-hr NiCd    battery for power during night side passes.  The science instruments    are mounted on three 2.5 m booms.  The Gamma Ray Spectrometer is    mounted on one boom, the Neutron Spectrometer and Alpha Particle    Spectrometers are mounted on another boom, and the Magnetometer and    Electron Reflectometer are mounted on the third boom.  The    Magnetometer instrument is mounted on a 1.2 m long boom extending    beyond the main boom to isolate it from the Electron Reflectometer.    The spacecraft bus houses three fuel tanks, six engines, and five    electronic units.  The fuel tanks at launch hold 138 kg of hydrazine    pressurized with helium.  There are two aft axial engines, two    forward axial engines, and two tangential engines.    The communication system consists of an S-band transponder, an omni    antenna with 3-pi steradian antenna pattern for uplink and downlink,    and a medium gain antenna for downlink.  The engineering-only    downlink data rate is 300 bps and the science/engineering downlink    data rate is 3600 bps.    Command and control of the spacecraft is achieved by a simple    Command and Data Handling (C&DH) unit.  As an individual command is    uplinked to the spacecraft, the C&DH directs the command to the    appropriate subsystem.  All science and engineering data are    collected by the C&DH and then are buffered and formatted for    downlink by the C&DH.  The data are downlinked at 1800 bps    immediately and simultaneously dumped into a solid state recorder.    The data stored on the solid state recorder is downlinked 53 minutes    later.  These delayed data frames are interleaved into the real-time    data stream, yielding a total downlink rate of 3600 bps.  The    purpose of the delayed stream is to receive data acquired during    communications blackout periods and to eliminate the need for a    commandable data recorder.    The LP spacecraft clock or frame counter increments once every 2    seconds.  It is stored in a 24-bit register.  This means that the    clock will reset after about 33.5 million seconds or about once per    year.  The clock reset on January 30, 1999 at about 12:09 UTC, which    was early in the Extended Mission.  Spacecraft Coordinate System  ============================    The Trans-Lunar Injection (TLI) stage and spacecraft body    coordinate system is discussed below.  The origin of    coordinates is: a) in the separation plane between the    spacecraft and the adapter of the TLI stage; and b) at the    geometric center of the equilateral triangle defined by the    bolt holes for the separation nuts.    The Z axis is normal to the separation plane.  The +Z direction    is towards the medium gain antenna (forward) end of the    spacecraft.  The X axis is in the separation plane between the    spacecraft and the adapter of the TLI stage.  The -X direction    is parallel to the centerline of instrument boom No.  1 and    towards the Gamma Ray Spectrometer.  The Y axis is defined by    the right-hand rule.  Instrument Host Overview - DSN  ==============================    The Deep Space Network (DSN) is a telecommunications facility    managed by the Jet Propulsion Laboratory of the California Institute    of Technology for the U.S. National Aeronautics and Space    Administration (NASA).    The primary function of the DSN is to provide two-way communications    between the Earth and spacecraft exploring the solar system.  To    carry out this function it is equipped with high-power transmitters,    low-noise amplifiers and receivers, and appropriate monitoring and    control systems.    The DSN consists of three complexes situated at approximately    equally spaced longitudinal intervals around the globe at Goldstone    (near Barstow, California), Robledo (near Madrid, Spain), and    Tidbinbilla (near Canberra, Australia).  Two of the complexes are    located in the northern hemisphere while the third is in the    southern hemisphere.    Each complex includes several antennas, defined by their diameters,    construction, or operational characteristics: 70-m diameter,    standard 34-m diameter, high-efficiency 34-m diameter (HEF), and    34-m beam waveguide (BWG).  These DSN complexes, in conjunction with    telecommunications subsystems onboard planetary spacecraft,    constitute the major elements of instrumentation for radio science    investigations.    For more information see [ASMAR&RENZETTI1993].  Science Packages  ================    The Lunar Prospector spacecraft has five science instruments.  The    instruments are a Gamma Ray Spectrometer (GRS), a Neutron    Spectrometer (NS), an Alpha Particle Spectrometer (APS), a    Magnetometer (MAG), and an Electron Reflectometer (ER).  A Doppler    Gravity Experiment (DGE) uses Doppler tracking data for deriving    gravity measurements.  In addition, the spacecraft spin rate and    attitude are determined on the ground from data derived from a sun    sensor and an IR Earth/Moon limb crossing sensor.