3rd Qrtr > 4th Qrtr
Mission Status 2007
Kevin V. Gilliland Stardust Spacecraft Team
September 19, 2007
Stardust is continuing its quiescent cruise and all subsystems are nominal. There were several Deep Space Network tracks during the past week. One of the major challenges facing this mission is the need to conserve fuel. Conserving fuel would ensure the largest possible time of arrival maneuver could be performed, as planned, approximately one year before the encounter with Tempel 1. This adjustment in time of arrival maximizes the probability of imaging the Deep Impact crater. The Spacecraft Team has taken the action to improve attitude dead-band performance by updating the spacecraft’s mass properties parameters. The Stardust spacecraft was designed to maintain its attitude knowledge, during cruise, by using Star Camera images taken every second. This allows the spacecraft to stay within the desired dead-bands, currently 2-2-10 (X, Y, Z). The revised parameters will be implemented on the spacecraft during the planned DSN track on Monday, September 24. If the performance is as expected the permanent implementation will be made on September 27. Investigation into the cause of the EEPROM byte corruption is continuing. The corruption has been duplicated in the Spacecraft Test Laboratory and the initial results indicate the spacecraft is not at risk if a reboot were to happen.
September 12, 2007
Stardust is continuing its quiescent cruise and all subsystems are nominal. There have been many Deep Space Network tracks during the past week. The project has decided to delay the execution of DSM 1 to October 10, 2007 to allow additional tracking and planning time for the development of the maneuver parameters. An internal meeting was held to assign action items to determine the cause of the EEPROM byte corruption and identify any impacts to spacecraft operation. Since the corruption is in an unused portion of the EEPROM, our initial assessment is no threat to the spacecraft. Our first task is to confirm that assessment. Weekly meeting are scheduled to track the progress.
September 6, 2007
Stardust is continuing its quiescent cruise and all subsystems are nominal. There have many Deep Space Network tracks in support of the upcoming Deep Space Maneuver on September 19. Background sequence SN002 successfully starting execution on Sunday and the first task is to perform CRC checks of Stardust’s memories. The check of the file system in EEPROM did not match the ground truth indicating that some location has been corrupted. During the DSN track on Tuesday we downloaded the affected area of memory to determine where the change occurred and to assess the impact if a reboot were to occur. During a reboot the code contained in EEPROM is copied to DRAM where it executes. A corrupted EEPROM, depending on the location, could prevent the spacecraft from booting on Side A and would result in a swap to the B side. The team will be examining the memory dump and comparing with the Spacecraft Test Laboratory to determine the best course of action to correct the situation. The Deep Space Maneuver (TCM-21) is scheduled to execute on September 19 and is a 5 m/s burn. This maneuver will place the spacecraft on a trajectory to perform an Earth Gravity Assist in January 2009.
August 29, 2007
Stardust continues its quiescent cruise. All subsystems are nominal. There have been five DSN contact passes since the previous report. Passes are configured to provide ranging data for Navigation in support of the upcoming Deep Space Maneuver. The second background sequence has been prepared and will begin executing next week.
The Deep Space Maneuver (TCM-21) is scheduled to execute on September 19 and is a 5 m/s burn. This maneuver will place the spacecraft on a trajectory to perform an Earth Gravity Assist in January 2009.
August 22, 2007
Stardust continues its quiescent cruise while passing through perihelion this week, 0.92 AU (approximately 85,000,000 miles) from the sun. The first NExT background was successfully loaded onto the spacecraft during the communication track on Tuesday, August 21. The Deep Space Maneuver is presently scheduled to execute on September 19 and is a 5 m/s burn. This maneuver will place the spacecraft on a trajectory to perform an Earth Gravity Assist in January 2009.
August 16, 2007
On Monday, August 13th, at 3:39 (MDT) the STARDUST spacecraft responded, as expected, to its first “phone home” commands since February 8, 2007. The spacecraft was on side A with no reboots and all subsystems were excellent and looked like the last time we saw it. After confirming the state of the spacecraft we commanded the spacecraft out of safe mode and back into nominal cruise mode. During the second pass on Thursday, August 16th, the team continued the re-awakening process by sending commands to provide a history of spacecraft activities for the last five months. Preparations for the first background sequence are in progress.
August 8, 2007
The Stardust spacecraft is currently exiting from solar conjunction and is 281 million Km from Earth. We are developing command products to re-establish contact on Monday August 13th. After re-establishing communications we will assess the health of the spacecraft and take it out of hibernation mode. A Deep Space Maneuver is planned for mid-September to target an Earth flyby in January 2009. The Stardust-NExT (New Exploration of Tempel 1) mission is to flyby the comet Tempel 1 on February 14, 2011 in order to obtain high resolution images of the coma and nucleus, as well as measurements of the composition, size distribution, and flux of dust emitted into the coma. We have developed a reliable plan to update knowledge of the rotational phase of the comet sufficiently well to have a high probability of viewing significant portions of the hemisphere studied by Deep Impact (DI) in 2005 and a high probability of imaging the crater made by its impactor. The impact event produced so much ejecta that DI did not succeed in imaging the crater.