NEAR Mission Status Report 05 May 2000

MISSION OPERATIONS:
 
NEAR Shoemaker remained in Operational Mode with Flight Computer #1 and Attitude Interface Unit #2 in control of spacecraft attitude.  Except for two brief periods, the spacecraft instrument suite remained "ON" and operational throughout the 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.
 
As previously mentioned, there were two periods this past week when the full instrument complement was not operational.  The MSI was offline from day 121 at 13:22 UTC till 00:15 UTC the next day, approximately 11 hours. Fortunately, there were no MSI science activities scheduled during this period and instrument science was not effected.  Unfortunately, the critical OpNavs scheduled 1.5 and 4.5 hours after OCM 6 were lost. Routine daily OpNavs acquired later the next day substituted for the lost critical OpNavs.
 
The NLR went offline on day 123 at 09:02:08 UTC when the instrument over-current rule tripped.  Approximately 4.5 hours later, during the subsequent high gain DSN track, the instrument was turned back on 13:36:04 UTC.  Approximately 4 hours later, at 17:32:25 UTC, the NLR was promoted to its flight application to resume weekly science activities.  With approval from the NLR instrument engineer and Spacecraft System Engineer, the NLR over current autonomy rule act-on count was increased from 2 seconds to 3 seconds to prevent a re-occurrence.
 
Science activities conducted this week included Eros observations by the full instrument suite: MSI, NIS, MAG, NLR and XGRS.  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:
 
July 7  Eros Orbit Correction Maneuver 7  (50km x 35km transfer orbit) July 14 Eros Orbit Correction Maneuver 8  (35km orbit circularization) July 23 Eros Orbit Correction Maneuver 9  (35km x 50km transfer orbit) July 30 Eros Orbit Correction Maneuver 10 (50km orbit circularization)