NASA's Chandra X-Ray Observatory Safe Mode Fault Identified, Normal Operations To Resume

Earlier this week NASA reported that its Chandra X-ray Observatory had ceased normal operations and had entered safe mode. The fear was that the space telescope might have suffered a gyroscope failure. Chandra entered safe mode on October 10 and NASA says that operations will resume with the cause of safe mode now identified.

The gyroscope inside the space telescope was the root cause of Chandra entering safe mode, but the gyroscope hasn't failed completely. NASA reports that safe mode was caused by a "glitch" in the gyroscope that resulted in a 3-second period of bad data that led the onboard computer to calculate an incorrect momentum for the spacecraft. When Chandra identified that data as erroneous, it entered safe mode.

To rectify the issue, NASA says that the team operating Chandra switched to the backup gyroscope and placed the gyroscope with the glitch in reserve. The team has to apply pre-tested flight software updates before returning Chandra to normal operations.

Normal operations are expected to resume by the end of the week. When the spacecraft entered safe mode, several things happened. Safe mode is designed to swap critical hardware to backup units and to rotate the observatory so that the solar panels get maximum sunlight.

NASA scientists say that the transition to safe mode was normal behavior for Chandra with the event that occurred. Like many of NASA's spacecraft exploring the solar system, Chandra is functioning well beyond its expected lifetime. The observatory is 19-years old and was originally expected to operate for five years before having its life extended to ten years.

SOURCE: NASA