Lunar Prospector Status Report #23

March 6, 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. This past week, mission controllers executed no commands to the spacecraft. The current state of the vehicle (as of 4:00 p.m. (PST) on Thurs., March 5, 1998), according to Mission Operations Manager Marcie Smith, is as follows:

Spacecraft Orbit Number:	650
Data Downlink Rate:	3600 bps
Spacecraft Spin Rate:	11.94 rpm
Spin Axis Attitude:	Longitude: 344 deg Latitude: 88.8 deg
Trajectory:	Periselene: 82 km Aposelene: 117 km
Period:	118 minutes duration
Inclination:	90.0 deg
Occultations:	none
Eclipses:	45 minutes duration

Late last week, mission controllers exeperienced a 15-hour period in which they could not track the vehicle. Since then, tracking allocations have been much better, and only a few short outages are anticipated.
Ames mission controllers plan to execute the first orbit trim maneuver over the weekend. At that time, two axial burns are scheduled: one to raise orbital periselene (closest distance from the Moon) and one to lower orbital aposelene (furthest distance from the Moon). Although the targeted orbit following this maneuver will not be exactly 100 km circular, the new orbit (87 km by 113 km) is designed to be better able to compensate for periodic perturbations, thus maintaining the desired 100 (+ or -) 20 km orbit for a longer time.

Alison Davis
Lunar Prospector Mission Office
NASA Ames Research Center
Moffett Field, Calif. 94035