Lunar Prospector Status Report #70

February 19, 1999 - 1:00 p.m. EST (10:00 a.m. PST)

The Lunar Prospector spacecraft is operating well and collecting 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.

Cycling of the spacecraft transmitter continues. The transmitter is powered off for occultations (when the spacecraft goes behind the moon and no data is received at Earth anyways) to reduce battery drain during propellant tank heater events.

On Feb 16 (DOY 047), there was an annular solar eclipse, which caused a 3 hour outage in LP data.

Three commands were sent this week (DOY 047) to read out the MAG/ER memory.

Current spacecraft state (0000 GMT 2/19/99, DOY 050):

Orbit: 4957
Downlink: 3600 bps
Spin Rate: 12.09 rpm

Spin Axis Attitude (ecliptic):
Latitude: -88.8 deg
Longitude: 280 deg

Trajectory:
Periapsis Alt: 20.0 km
Apoapsis Alt:40.0 km
Period: 111 min

Occultations: 49 minutes
Eclipses:47 minutes
Propellant Remaining: 15.95 kg