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Mission Status 2009
Kevin V. Gilliland Stardust Spacecraft Team
October 7, 2009
All subsystems are nominal. Stardust's most recent contact was yesterday, Tuesday, October 6. The next will be Tuesday, October 13. Attitude control continues to be efficient. The spacecraft was moved to a Sun pointing attitude during the long periods between contact periods, and, since no antenna pointing was required, wider 10-deg deadbands were used. All small forces data packets were received and processed successfully. Occasional star camera outages and Z-axis control error counts continue, as expected. The star camera is now pointing toward the constellation Sagittarius. Jupiter is also in the field of view. The Lockheed-Martin program manager and JPL project manager traveled to Finland last month, to meet with the Comet and Interstellar Dust Analyzer (CIDA) science team. The meeting served to plan CIDA's role in the coming Tempel-1 Encounter. Stardust is now 1.71 AU (approximately 159 million miles) from the Sun, and 1.72 AU (approximately 160 million miles) from the Earth. Stardust is near aphelion of its 1 ½ year orbit.
Background sequence SN029 is executing now.
October 21, 2009
All subsystems are nominal. Stardust's most recent contact was Saturday, October 17. The next will be later today. Earlier this month, the spacecraft was oriented to perform a calibration. Stardust was moved to an attitude—relative to the Sun—similar to our approach to Tempel-1 in January, 2011. The spacecraft remained in the calibration attitude for 48 hours in order to estimate the solar torque to improve the trajectory small forces modeling. Last week, project scientists presented findings from recent Hubble and Earth-based observations of Tempel-1. Observations are required to determine the rotation period of the comet and the phasing of surface features to plan our arrival time. Preliminary findings show that the rotation period is well known, with more study required to determine the time of arrival.
Background sequence SN029 is executing now, with SN030 ready to load.
October 28, 2009
All subsystems are nominal. Stardust's most recent contact was Saturday, October 24. The next will be Thursday, October 29. When not in contact, the spacecraft commands its processing rate from 20 MHz to 10 MHz. The processor rate change has the effect of changing the temperature of the processing and interface components. Thermal engineers monitor the temperature of one of the interface components, in order to avoid a temperature range of 43 °C to 45 °C. Throughout the mission, we have seen that the interface is vulnerable to spontaneous resets when in this range. Commanding to 10 MHz between passes brings the temperature of the interface below 43 °C. While the resets are rare and well-tolerated, the temperature range is avoided when possible. Flight Software engineering monitors the processor load at each speed; the lower rate has no negative effect on processing between contact periods. Systems engineers have been calibrating the Comet and Inter-Stellar Dust Analyzer (CIDA) sensitivity threshold. In recent passes they’ve collected data on how sensitivity levels are compatible with an assumed particle-free environment.Background sequence SN029 is executing now. Sequence SN030 is on board and will be the active sequence November 1.
