Kepler Mission Manager Update
On July 4, Kepler passed a point 12,500,000 kilometers (7,767,140 miles) from Earth. In a regularly scheduled communication with Kepler on July 2, engineers determined the spacecraft had entered safe mode. Safe mode is a self-protective measure that a spacecraft takes when a malfunction occurs. Engineers diagnosed the health and safety of the spacecraft subsystems. All subsystems were found to be normal, with the photometer turned off (the photometer is automatically turned off in a safe mode event). After downloading engineering health and status files, the Kepler project team continued taking steps to return the spacecraft to science operations. Science data collected since June 19 were downloaded to ground controllers, the photometer was powered back on, and Kepler was reoriented back to its science data collecting attitude. By late July 3, Kepler had returned to normal science operations.
Engineers determined that this event was caused by a processor reset, as it was with a similar safe mode event on June 15. They continue to evaluate data from both events to determine their root cause.