K3PGP Experimenter's Corner
Lunar Prospector Status Report #20
Feburary 18, 1998 - 7:00 p.m. EST (4:00 p.m. PST)
The Lunar Prospector spacecraft continues to perform very well, and all instruments continue to collect good data, according to Mission Control at NASA's Ames Research Center. The current state of the vehicle (as of 4:00 p.m. (PST) on Wed., Feb. 18, 1998), according to Mission Operations Manager Marcie Smith, is as follow:
| Orbit Number: | 455 | ||
| Data Downlink Rate: | 3600 bps | ||
| Spacecraft Spin Rate: | 11.94 rpm | ||
| Spin Axis Attitude: | Longitude:
350 deg Latitude: 88.6 deg |
||
| Trajectory: | Periselene: 85km | Aposelene: | 115 km |
| Period: | 118 minutes duration | ||
| Occultations: | 43 minutes duration | ||
| Inclination: | 90.3 deg | ||
| Eclipses: | 42 minutes duration |
Last week, a small re-orientation maneuver was performed in order to reposition the spacecraft so that the sun shines slightly atop the vehicle. Mission controllers performed the maneuver on Tues., Feb. 10, 1998 according to the following schedule: Thruster heaters turned on: 2:29 p.m. (PST) A1/A4 thrusters fired (12 0.2 second pulses): 2:55 p.m. (PST) Thruster parameters reset: 2:57 p.m. (PST) A total of 13 commands were executed to perform this maneuver, which was expected to shift the spacecraft's spin axis by 1.7 degrees. This would have placed the sun equatorial angle at 1.0 degrees. Actual performance was slightly higher than expected, shifting the vehicle's spin axis approximately 1.84 degrees and putting the sun equatorial angle at 1.25 degrees.
Alison Davis
Lunar Prospector Mission Office
NASA Ames Research Center
Moffett Field, Calif. 94035
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