The onboard pointing performance of the OrbView-2 (OV-2) spacecraft for the first five years of the SeaWiFS mission is presented. Adjustments to the onboard attitude control system (ACS) since launch are described, and various issues and anomalies regarding the performance are discussed. Overall, this relatively low-cost spacecraft has performed quite effectively after various in-flight adjustments, however, a variety of sensor and computational anomalies have caused occasional minor pointing disturbances. Many of these disturbances have implications for the navigation processing performed for the science data by the Sea-viewing Wide Field-of-view Sensor (SeaWiFS) Project at the NASA Goddard Space Flight Center. Possible further adjustments to the OV-2 ACS have been investigated which could lead to improved pointing performance, and conclusions from these analyses are presented. Some of the various sensor and software anomalies are fairly well understood, but some others remain puzzling. Particularly vexing are various timing anomalies resulting from the way the clocks for three separate onboard processors are synchronized to each other and Global Positioning System (GPS) time. The pattern of occurrence of some of the sensor anomalies could merit further review and trending, which may be useful to monitor for any degradation in performance as the mission continues.
