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Mission Status 2009
Kevin V. Gilliland Stardust Spacecraft Team
October 31, 2009—Special Report
At the start of Thursday’s DSN pass Stardust-NExT was acquired in safe mode. Analysis of the recorded data showed the spacecraft entered safe mode late Monday evening.The Attitude Knowledge Performance Monitor requested safe mode because the Star Camera failed to respond to commands issued by the processor. Also impacted were the CIDA instrument and the Sun Sensor. Both of these components were not able to communicate with the processor. The Sun Sensor returned to nominal operations during the safe mode execution and the Star Camera returned to nominal after it was power cycled as part of the response by the Safe Mode Executive. CIDA will be returned to nominal operations during our DSN pass on Monday, November 2. This safe mode was nearly identical to the Oct 2003 safe mode event. That entry was caused by a solar flare that caused communications problems with the Star Camera, Sun Sensor, CIDA and Navigation Camera. Interestingly, that same day in October 2003, the Genesis and Odyssey spacecrafts also entered safe mode due to the same solar flare. The investigation into the cause of the current event is continuing. The spacecraft team successfully exited safe mode during Saturday’s afternoon pass and returned spacecraft operations to normal.
November 4, 2009
All subsystems are once again nominal, after an eventful week. Stardust entered Safe Mode at 09-300/01:59:47 (Monday, October 26) while out of contact. The flight computer’s communication with the Star Camera was interrupted, resulting in a request for Safe Mode. While the Star Camera communication errors persisted, the spacecraft performed a Sun Search slew, then began Sun Coning in order to provide a power-safe attitude. Safe Mode’s actions eventually cleared the error; with valid Star Camera images, the spacecraft left Sun Coning to Sun Point. Later, Safe Mode configured for Earth Point communication using the Medium Gain Antenna, and waited for our contact. The spacecraft was found in Safe Mode when the Thursday, October 29, contact began. All recovery steps were executed successfully and Stardust returned to normal operations Saturday, October 31. Safe Mode recovery was accomplished with our scheduled contact periods; no requests for additional DSN coverage were required. Investigation into the cause of the Safe Mode entry continues. The most recent contact was Monday, November 2. The next is later today. Sequence SN030 is now the active sequence.
November 11, 2009
All subsystems are nominal.The most recent contact was Sunday, November 8. This has been a busy week, with 4 passes since the previous report. The next pass, however, is not until Tuesday, December 1. Thermal engineers have kept a close eye on the interface card temperatures. Between passes the temperature is reduced by using a slower 10 MHz processor speed. Lowering the temperature avoids a thermal region of known sensitivity, where resets are more frequent. This week Stardust passes aphelion, the last of this Tempel-1 mission. The spacecraft is 1.73 AU from the Sun. Stardust is 2.08 AU from Earth, and the range continues to increase, as Earth is moving faster (relative to the Sun) than the spacecraft. Sequence SN030 is now the active sequence. SN031 is on board and will become active Sunday, November 30.
