Newsletter

Title : The Lunar prospectus
Author : J. H. King
Date :

The Lunar Prospector will be deliberately targeted to impact in a permanently
shadowed area of an unnamed polar crater on the Moon at 09:51 UT (5:51 a.m.
EDT) on July 31. It is hoped that the impact will create a plume of water
which will be visible from Earth. The partial lunar eclipse on July 28 did
not cause problems for the spacecraft, see the Flight Status Report for more.

Lunar Prospector

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Launch Date: 7 January 1998 UT 02:28:44 (6 January 9:28:44 p.m. EST)
Launch Vehicle: Athena II
Launch Site: Kennedy Space Center
Launch Mass 296 kg (fully fueled), 158 kg (dry)
Power System: Body Mounted 202 W Solar Cells and 4.8 amp-hr NiCd Battery

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Flight Status Report
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The Lunar Prospector is designed for a low polar orbit investigation of the
Moon, including mapping of surface composition and possible polar ice
deposits, 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
understanding of the origin, evolution, current state, and resources of the
Moon. The spacecraft is a graphite-epoxy drum, 1.37 meters in diameter and
1.28 meters high with three radial instrument booms. It is spin-stabilized
and controlled by 6 hydrazine monopropellant 22-Newton thrusters.
Communications are through two S-band transponders and a slotted,
phased-array medium gain antenna and omnidirectional low-gain antenna. There
is no on-board computer, ground command is through a 3.6 kbps telemetry link.
Total mission cost is about $63 million. After launch, the Lunar Prospector
had a 105 hour cruise to the Moon, followed by insertion into a near-circular
100 km altitude lunar polar orbit with a period of 118 minutes. In December
1998 the orbit was lowered to 40 km. The nominal mission ended after one
year, at which time the orbit was lowered to 30 km. On 31 July 1999 Lunar
Prospector will impact the Moon near the south pole.

Scientific Investigations
Gamma Ray Spectrometer (GRS) - G. Scott Hubbard, NASA Ames
Neutron Spectrometer (NS) - William Feldman, Los Alamos
The GRS and NS will return global data on elemental abundances, which will be
used to help understand the evolution of the lunar highland crust and the
duration and extent of basaltic volcanism, and to assess lunar resources. The
NS will also locate any significant quantities of water ice which may exist
in the permanently shadowed areas near the lunar poles.
Magnetometer (MAG) - Mario Acuna, NASA Goddard; Lon Hood, Univ. of Arizona LPL
Electron Reflectometer (ER) - Robert Lin, UC Berkeley SSL
The MAG/ER experiments will return data on the lunar crustal magnetic field
and the lunar induced magnetic dipole. These data will help provide an
understanding of the origin of lunar paleomagnetism and the degree to which
impacts can produce paleomagnetism, and allow constraints on the size and
composition of the (possible) lunar core.

Alpha Particle Spectrometer (APS) - Alan Binder, Lockheed
The APS instrument will be used to find radon outgassing events on the lunar
surface by detecting alpha particles from the radon gas itself and its decay
product, polonium. Observations of the frequency and locations of the gas
release events will help characterize one possible source of the tenuous
lunar atmosphere. Determination of the relationship of outgassing sites with
crater age and tectonic features may be possible. This may in turn be used to
characterize the current level of lunar tectonic activity.

Doppler Gravity Experiment (DGE) - Alex Konopliv, NASA JPL
This investigation will use Doppler tracking of S-Band radio signals to
characterize the spacecraft orbit and determine the lunar gravity field. This
data will provide information on the lunar interior and, combined with lunar
topographic data, will allow modelling of the global crustal asymmetry,
crustal structure, and subsurface basin structure. It can also used for
planning future lunar missions.

Lunar Prospector Project Management
Principal Investigator - Alan Binder, Lockheed
Mission Manager - G. Scott Hubbard, NASA Ames
Assistant Mission Manager - Sylvia Cox
Project Manager - Thomas A. Dougherty

The Lunar Prospector mission has been selected by NASA for full development
and construction as part of NASA's Discovery program.

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NSSDC Planetary Home Page
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Author/Curator:
Dr. David R. Williams, [email protected]
NSSDC, Mail Code 633
NASA Goddard Space Flight Center
Greenbelt, MD 20771
+1-301-286-1258

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NASA Official: J. H. King, [email protected]
Last Updated: 29 July 1999, DRW