Terra Weekly Mission Status Update Weekly Update Archive May 28 - June 3, 2004 The Terra spacecraft is operating nominally. All five instruments are in science mode. There will be no MODIS lunar calibration roll maneuvers for the month of June due to the fact that the lunar view would require a roll in excess of the maximum value of 20 degrees allowed by the mission rules. On Wednesday, May 19 (DOY 140), MISR scheduled three calibration activities requiring movement of the goniometer. Two of the three calibrations events proceeded normally, but the goniometer did not return to the correct position following one of the events after being specifically commanded to a specific position. Analyzing this incident, the MISR Instrument Operations Team (IOT) informed the Flight Operations Team (FOT) that the instrument occasionally exhibits what they describe as a known “idiosyncrasy,” where under certain circumstances the goniometer OFF position command does not execute properly. Additional calibrations were pre-empted until analysis of the incident could be completed by the MISR team. Extensive testing using the MISR engineering testbed was performed by JPL engineers during the week subsequent to the calibration incident. This testing has confirmed the known behavior of the goniometer mechanism. It is concluded that the incorrect homing and stoppage in the wrong position observed during the calibration sequence of May 19 was a manifestation of the idiosyncrasy that occurs occasionally, and is not an issue. New calibrations are expected to be scheduled in the next reporting period.