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Lunar Prospector Status Report #62 December 21, 1998 - 1:00 p.m. EST (10:00 a.m. PST) The Lunar Prospector spacecraft is operating well and all instruments continue to collect good data. On Saturday, December 19, the spacecraft was placed into a orbit with an average altitude of 40 km. This is a transition orbit, between the nominal mapping orbit (with altitude 100 km) and the extended mission orbit (with altitude 25-30 km), where the gravity model will be verified. The timeline is given below: 353/1740 cmd'd thruster heaters on 353/1811 fired A3/A4 thrusters for 46.8 sec 353/1840 cmd'd thruster heaters on 353/1911 fired A1/A2 thrusters for 150.4 sec 353/1917 cmd'd thruster heater on 353/1937 fired T1 thrusters for 0.65 sec The starting orbit was 77.5 km x 122.5 km. The first burn was at apoapsis to lower periapsis from 77.5 km to 50.5 km. The second burn was at the ascending node to set new periapsis altitude to 25 km at desired argument of periapsis. The resulting orbit was 25 km x 55 km. The gravity field will tend to circularize it over the next few days. The attitude reorientation maneuver was cancelled and the third burn trimmed the spacecraft spin rate back to its nominal value. There were very high winds in the California high desert and there was concern that the antenna (DSS 27) would have to be stowed mid-way during the maneuver, but fortunately the winds stayed below the limits and everything went on time. Eclipses started as predicted at 353/2005 but their length will decrease with time and the season will end before Christmas.   Current spacecraft state (0000 GMT 12/21/98): Orbit: 4184 Downlink: 3600 bps Spin Rate: 12.00 rpm Spin Axis Attitude (ecliptic): Latitude:-88.0 deg Longitude: 242 deg Trajectory: Periapsis Alt: 29 km Apoapsis Alt: 52 km Period: 112 min Occultations: 10 minutes Eclipses: 23 minutes Propellant Remaining: 17.45 kg       brief summary of terms detailed summary of terms