Lunar Prospector Status Report #87

June 18 , 1999 - 1:00 p.m. EST (10:00 a.m. PST)

The Lunar Prospector spacecraft continues to collect good science data in the extended mission orbit. Four of five science instruments are on: the Gamma Ray Spectrometer (GRS), the Neutron Spectrometer (NS), the Magnetometer (MAG), and the Electron Reflectometer (ER). Data continues to be collected for the Doppler Gravity Experiment (DGE) as well.

The transmitter was turned off for a short interval only once this week during an eclipse period when the propellant tank heater was on. The battery voltage remained within green limits all week. As eclipse have gotten shorter (the season ends in about a week and then there is a 3 week period with no eclipses at all), it is expected that transmitter cycling will not be required again on a regular basis.

The GRS gain setting was tweaked on 6/11.

All commands (6 total) executed normally this week.

Current spacecraft state (0000 GMT 6/18/99, DOY 169):

Orbit: 6498
Downlink: 3600 bps
Spin Rate: 12.12 rpm

Spin Axis Attitude (ecliptic):
Latitude: -88.5 deg
Longitude: 048 deg

Trajectory:
Periapsis Alt: 14.1 km
Apoapsis Alt: 45.9 km
Period: 111 min

Occultations: 46 minutes
Eclipses: 32 minutes
Propellant Remaining: 10.68 kg
The next orbit maintenance burn is scheduled for June 28, GMT (afternoon of June 27, PST).