Lunar Prospector Status Report #78

April 16, 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.

Investigation into the commanding anomaly continues. Since the last report, all commands (a total of 26) have executed normally.

During the last week, there have been 4 (of 11) occurrences of the battery voltage reaching the yellow low-voltage limit during an eclipse while the propellant tank heater was on.

Current spacecraft state (0000 GMT 4/16/99, DOY 106):

Orbit: 5682
Downlink: 3600 bps
Spin Rate: 12.09 rpm

Spin Axis Attitude (ecliptic):
Latitude: -89.0 deg
Longitude: 014 deg

Trajectory:
Periapsis Alt: 12.4 km
Apoapsis Alt: 47.6 km
Period: 111 min

Occultations: 49 minutes
Eclipses: 49 minutes
Propellant Remaining: 13.61 kg

The next orbit maintenance burn is scheduled for late in the afternoon local time on April 20 (DOY 111 GMT).