NEAR Mission Status Report 23 June 2000
MISSION OPERATIONS:
During this past week, NEAR Shoemaker remained in Operational Mode with Flight Computer #1 and Attitude Interface Unit #2 in control of spacecraft attitude. Except for the Near-Infrared Spectrometer (NIS), the spacecraft instrument suite remained "ON" and operational this week.
NEAR Shoemaker is presently in a nominal 50 km circular orbit around Eros. The spacecraft entered this orbit April 30, 2000 at 16:15 UTC when Orbit Correction Maneuver 6 (OCM 6) was executed. According to the current long term trajectory plan, NEAR Shoemaker will remain in this orbit conducting Science observations until July 7, 2000 at 18:00 UTC when Orbit Correction Maneuver 7 (OCM 7) will initiate the 50 km x 35 km transfer orbit.
Since the next planned OCM is not scheduled until July 7, weekly Momentum Correction Maneuvers (MCM) are required to manage spacecraft system momentum. Beginning May 10, these maneuvers are scheduled every Wednesday until June 28. The seventh MCM of this period, MCM 9, was successfully executed this past Wednesday, June 21, at 16:00 UTC. The achieved momentum was well within operational tolerances, and the imparted delta V was minor.
Version 7 of the NLR flight application software was successfully loaded, dumped, and verified during Wednesday’s high gain DSN track, DOY 173. NLR software version 6 remained operational until Thursday morning (DOY 174) when the NLR was promoted to version 7. Following promotion, a realtime operational test of the revised software was successfully performed. During this test, 1 Hertz and 2 Hertz pulse repetition frequencies were exercised as well as an Auto-Acquisition sequence. Following this test, the NLR was reconfigured for 1 Hertz operation, consistent with the weekly command load, and resumed science data collection.
Except for the NIS, science activities conducted this week included Eros observations by the full instrument suite: MSI, MAG, XGRS and NLR. Please consult science timelines for more details.
Upcoming Spacecraft Activities:
In addition to regular Eros Science and Optical Navigation, the following are operationally significant activities planned for the NEAR Shoemaker mission operation:
June 28 Momentum Correction Maneuver 10
July 7 Eros Orbit Correction Maneuver 7 (50 x 35 km transfer orbit) July 14 Eros Orbit Correction Maneuver 8 (35km orbit circularization) July 24 Eros Orbit Correction Maneuver 9 (35 x 50 km transfer orbit) July 31 Eros Orbit Correction Maneuver 10 (50km orbit circularization)
