Lunar Prospector
Lunar Prospector
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| Mission type | Lunar orbiter |
|---|---|
| Operator | NASA |
| COSPAR ID | 1998-001A |
| SATCAT no. | 25131 |
| Mission duration | 570 days |
| Spacecraft properties | |
| Bus | LM-100 |
| Manufacturer | Lockheed Martin |
| Launch mass | 295 kilograms (650 lb) |
| Dry mass | 126 kilograms (278 lb) |
| Power | 202.0 W |
| Start of mission | |
| Launch date | 7 January 1998, 02:28:44 UTC |
| Rocket | Athena II |
| Launch site | Cape Canaveral SLC-46 |
| Contractor | Lockheed Martin Space Systems |
| End of mission | |
| Decay date | 31 July 1999, 09:52:02 UTC |
| Orbital parameters | |
| Reference system | Selenocentric |
| Eccentricity | 0.00046 |
| Periselene | 99.45 kilometers (61.80 mi) |
| Aposelene | 101.2 kilometers (62.9 mi) |
| Inclination | 90.55 degrees |
| Period | 117.9 minutes |
| Epoch | 16 January 1998 |
| Lunar orbiter | |
| Orbital insertion | 11 January 1998, 10:28 UTC |
| Impact site | 87°42′S 42°06′E / 87.7°S 42.1°E |
| Orbits | ~7060 |
| Instruments | |
| Gamma ray spectrometer (GRS) Lunar Prospector neutron spectrometer (NS) Alpha particle spectrometer (APS) Doppler gravity experiment (DGE) Magnetometer (MAG) Electron reflectometer (ER) |
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Official insignia of the Lunar Prospector mission
Lunar Prospector is the third mission selected by NASA for full development and construction as part of the Discovery Program. At a cost of $62.8 million, the 19-month mission was 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. The mission ended July 31, 1999, when the orbiter was deliberately crashed into a crater near the lunar south pole after the presence of water ice was successfully detected.
Data from the mission allowed the construction of a detailed map of the surface composition of the Moon, and helped to improve understanding of the origin, evolution, current state, and resources of the Moon. Several articles on the scientific results were published in the journal Science.
Lunar Prospector was managed by NASA Ames Research Center with the prime contractor Lockheed Martin. The Principal Investigator for the mission was Dr. Alan Binder. His personal account of the mission, Lunar Prospector: Against all Odds, is highly critical of the bureaucracy of NASA overall, and of its contractors.
The spacecraft was a graphite-epoxy drum, 1.36 m (4 ft 6 in) in diameter and 1.28 m (4 ft 2 in) high with three radial 2.5 m (8 ft 2 in) instrument booms. A 1.1 m (3 ft 7 in) extension boom at the end of one of the 2.5 m booms held the magnetometer. Total initial mass (fully fueled) was 296 kg (653 lb). It was spin-stabilized (nominal spin rate 12 rpm) with its spin axis normal to the ecliptic plane. The spacecraft was controlled by six hydrazine monopropellant 22-newton thrusters (two aft, two forward, and two tangential). Three fuel tanks mounted inside the drum held 138 kg (304 lb) of hydrazine pressurized by helium. The power system consisted of body-mounted solar cells which produced an average of 186 W and a 4.8 A·h rechargeable NiCd battery. Communications were through two S-band transponders, a slotted, phased-array medium-gain antenna for downlink, and an omnidirectional low-gain antenna for downlink and uplink. The on-board computer was a Harris 80C86 with 64 kilobytes of EEPROM and 64 kilobytes of static RAM. All control was from the ground, the computer echoing each command to the ground for verification there. Once the command was ground-verified, an "execute" command from the ground told the computer to proceed with execution of the command. The computer built telemetry data as a combination of immediate data and also read from a circular queue buffer which allowed the computer to repeat data it had read 53 minutes earlier. This simple solid-state recorder ensured that all data collected during communications blackout periods would be received, providing the blackout was not longer than 53 minutes.
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