NEAR Shoemaker Weekly Report 27 October 2000
MISSION OPERATIONS:
This past week has been one of the most intense periods of activity for the NEAR Shoemaker spacecraft since Eros Rendezvous. Since last Friday, the spacecraft has executed three propulsive maneuvers, safe mode entry and recovery, and most importantly a phenomenally successful 5.4 km Close Flyby of the asteroid 433 Eros.
NEAR Shoemaker entered a 50 km circular orbit last Friday, October 20 at 21:40 UTC, when Orbit Correction Maneuver 15 (OCM 15) successfully executed. In accordance with the mission plan, the spacecraft remained in this orbit until Wednesday, October 25 at 22:10 UTC, when Orbit Correction Maneuver 16 (OCM 16) injected the spacecraft into the 50 km x 21 km Close Flyby orbit. Eight hours and forty five minutes after executing OCM 16, the spacecraft was at closest approach, 5.4 km from the asteroid surface. Less than a day after OCM 16, Orbit Correction Maneuver 17 (OCM 17) was successfully executed, placing NEAR Shoemaker into a 63 km x 200 km transfer orbit. This last maneuver was performed Thursday, October 26 at 17:40 UTC. According to the mission plan, the spacecraft will remain in this orbit until November 3, when the orbit will be circularized at 200 km.
In addition to the three scheduled propulsive maneuvers and Close Flyby of the asteroid, the NEAR Shoemaker spacecraft demoted attitude mode to Earth Safe, October 24 (DOY 298) at 0000 UTC, when the last span of the current orbit expired. A new spacecraft ephemeris was scheduled to be loaded during the active High Gain Track in which the demotion occurred, but due to a red antenna at the ground station, Mission Operations was unable the load the new orbit before the last span of the current orbit expired. The spacecraft was returned to operational mode later the same day at approximately 1100 UTC. A Silver Lining: the revised "User Friendly Earth Safe Macro" incorporated into system safing autonomy prevented the Instrument Suite from being turned off during this safing event, reducing spacecraft recovery time and preserving instrument calibrations.
The zenith of the week occurred Thursday, October 26 at 06:55 UTC when the spacecraft passed within 5.4 km of Eros. Images collected during the Close Flyby sequence are simply phenomenal. The navigational team and Multi-Spectral Imager team are to be congratulated for the incredible effort involved in making this flyby such a success.
The spacecraft subsystem configuration has not changed during this reporting period.
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:
Nov 3 Eros Orbit Correction Maneuver 18 (200 km orbit circularization) Dec 7 Eros Orbit Correction Maneuver 19 (200 km x 35 km transfer orbit) Dec 12 Eros Orbit Correction Maneuver 20 (35 km orbit circularization)
