Lunar Prospector

NSSDC ID: 1998-001A

Description:
The Lunar Prospector was designed for a low polar orbit investig-
ation of the Moon, including mapping of surface composition and
possible deposits of polar ice, measurements of magnetic and
gravity fields, and study of lunar outgassing events. Data from the
19 month mission will allow construction of a detailed map of the
surface composition of the Moon, and will improve our under-
standing of the origin, evolution, current state, and resources of
the Moon. The spacecraft carries 6 experiments: a Gamma Ray
Spectrometer (GRS), a Neutron Spectrometer (NS), a Magneto-
meter (MAG), an Electron Reflectometer (ER), an Alpha Particle
Spectrometer (APS), and a Doppler Gravity Experiment (DGE).
The instruments are omnidirectional and require no sequencing.
The normal observation sequence is to record and downlink data
continuously. 

The spacecraft is a graphite-epoxy drum, 1.37 meters in diameter
and 1.28 meters high with three radial 2.5 m instrument booms.
A 1.1 m extension boom at the end of one of the 2.5 m booms
holds the magnetometer. Total initial mass (fully fueled) was 296
kg. It is spin-stabilized (nominal spin rate 12 rpm) with its spin
axis normal to the ecliptic plane. The spacecraft is controlled by
6 hydrazine monopropellant 22-Newton thrusters, two aft, two
forward, and two tangential. Three fuel tanks mounted inside the
drum hold 138 kg of hydrazine pressurized by helium. The power
system consists of body mounted solar cells which produce an
average of 186 W and a 4.8 amp-hr rechargeable NiCd battery.
Communications are through two S-band transponders, a slotted,