Status Report

NEAR Mission Status Report 26 May 2000

By SpaceRef Editor
May 26, 2000
Filed under


During this past week, NEAR Shoemaker remained in Operational Mode with Flight Computer #1 and Attitude
Interface Unit #2 in control of spacecraft attitude. Both the Near-Infrared Spectrograph (NIS) and the
X-Ray/Gamma Ray Spectrometer (XGRS) are currently disabled; the remainder of the spacecraft instrument suite
is “ON” and operational.

NEAR Shoemaker is presently in a nominal 50 km circular orbit around Eros. 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 third MCM of this period, MCM 5, was successfully executed this past Wednesday,
May 24, at 13:00 UTC. The achieved momentum was well within operational tolerances, and the imparted delta V
was minor.

The Flight Computer Scan Enable anomaly workaround was incorporated into the current spacecraft command load
and appears to be functioning correctly.

The XGRS autonomously turned off Thursday, DOY 146, at MET 134688448 (18:10:19 UTC) when the Disaster
Code was asserted by the instrument, tripping the XGRS Disaster Code autonomy rule. There are no further details
available at this time. Presently, the situation is being evaluated by cognizant XGRS personnel and Mission

The NIS instrument remains disabled. The instrument was disabled a week ago Saturday, DOY 134, when an
excessive power converter current was detected. NIS instrument engineers and scientists are analyzing relevant
data to determine possible explanations for the over current condition and propose a plan of attack. Tentatively,
the NIS will be re-enabled June 5, 2000 for approximately one minute to collect a snapshot of NIS telemetry.

Except for the NIS and XGRS, science activities conducted this week included Eros observations by the full
instrument suite: MSI, MAG 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:

May 31 Momentum Correction Maneuver 6

July 7 Eros Orbit Correction Maneuver 7 (50×35 km transfer orbit)

July 14 Eros Orbit Correction Maneuver 8 (35km orbit circularization)

July 24 Eros Orbit Correction Maneuver 9 (35x50km transfer orbit)

July 31 Eros Orbit Correction Maneuver 10 (50km orbit circularization)

SpaceRef staff editor.