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Mission Status 2009
Kevin V. Gilliland Stardust Spacecraft Team
June 20
All subsystems are nominal. Stardust had two passes this week. The next will be Tuesday, July 14. Stardust is now 1.42 AU (approximately 132 million miles) from the Sun. At this distance, the current produced by the solar array becomes too low. The solar array cell configuration is designed to be switched to operate over the large variation in the distance to the Sun encountered by the spacecraft in its long, elliptical orbits. Yesterday, commands were sent to switch to a parallel configuration to compensate and provide more current. The switch was successful, and the power system is operating well. String 2 thrusters continue to provide control, and the updated controller has reduced unnecessary firings due to star camera measurement noise. Daily fuel consumption, accordingly, is steady and near predictions. Background sequence SN025 is executing now. Sequence SN026 is on board, and will become active Sunday, July 12.
May 27
All subsystems are nominal. Stardust's most recent contact was Thursday, May 21. Stardust will now operate with monthly contacts. The next pass is Tuesday, June 16. Accordingly, the next status report will be sent on June 17. The propulsion fuel tank temperature has returned to almost nominal operating temperature. The tank was heated to collect fuel mass data. Propulsion trends show steady fuel consumption between 3.5 and 4.0 grams per day. Stardust is now 1.34 AU (approximately 125 million miles) from the Sun, and 0.37 AU (approximately 35 million miles) from Earth. From the spacecraft's view, Sun and Earth are currently separated by approximately 25 degrees. Background sequence SN024 is executing now. Sequence SN025 is on board, and will become active Sunday, June 14.
May 20
All subsystems are nominal. Stardust had three contacts this week. The next pass is tomorrow, Thursday, May 21. Propulsion and Thermal engineers continue their work to improve the accuracy of on-board fuel estimates. Last week, the fuel tank heaters were used to raise the temperature of the tank. This week, with the tank heaters set back to the usual operating temperature, the tank and its contents are slowly cooling. By analyzing the trend of the tank's temperature as it is cooling, a precise estimate of the remaining fuel mass will be derived. Today marks the 30th day since commanding to use string 2 thrusters. Attitude control is performing well and the rate of thruster firings is following predictions. Flight software executed commands to perform a memory defragmentation earlier today. This is done periodically to consolidate the available memory to improve processing time. Background sequence SN024 is executing now. Sequence SN025 is on board, and will become active Sunday, June 14.
May 13
All subsystems are nominal. Stardust had three contacts this week. The next pass is Sunday, May 17. Attitude control using the string 2 thrusters continues to perform well. Daily fuel consumption trends are following predictions. Propulsion and Thermal engineers are working to improve the accuracy of on-board fuel estimates. Background sequence SN023 is executing now. Sequence SN024 is on board, and will become active Sunday evening.
May 7, 2009
All subsystems are nominal. Stardust had two contacts this week. The next pass is tomorrow, Friday, May 8. By the end of May, we will reduce our contacts to one or two per month. Propulsion engineering trends and Navigation predictions compare favorably. As expected, fuel consumption is decreasing as the spacecraft's distance to the Sun increases. Earlier this week, a few obsolete parameter files were removed from the on-board file system. Background sequence SN023 is executing now and sequence SN024 will be sent next week.
