Stardust Status Report 27 October 2000

There were two Deep Space Network tracking passes during the past week.  During the first pass, the star camera reported that there were a few periods of several minutes in which it could only find three stars.  If the camera can detect two or fewer stars for more than three minutes, safe mode will be invoked.  In order to avoid entering safe mode, the decision was made to transition from all-stellar to gyro-based attitude
determination. This increased the time to two hours and allowed the star camera to detect less than three stars.  Once in gyro-based mode, the number of stars detected increased to five and remained there.
 
Commands were successfully sent to the spacecraft to take eight
images with the star camera and transmit them to Earth.  Early analysis of the images showed normal performance of the star camera.  These images contained many extra objects that are not in the on-board star catalog, including some of the bright stars in the Pleiades and the planet Saturn.  The investigation for the low number of stars is continuing.
 
After taking the images, the spacecraft was commanded back to
all-stellar mode. This will help preserve the inertial measurement unit’s limited life, about 3-9 months’ margin over the expected usage for the remainder of the mission.  Even though the longest outage was only twenty seconds, the star camera outage timer was increased to 5 minutes, thus providing an additional safety margin.
 
The investigation into the cause of the previous safe mode entry on October 4 has been traced to a flaw in the code that handles the communications between the star camera and the flight software. This can easily be corrected by a flight software patch, which is being designed.
 
The STARDUST Principal Investigator, Don Brownlee, made a presentation on the STARDUST Project to the engineering departments at the University of Washington.  The STARDUST Outreach team supported the Division of Planetary Science Conference with a Thematic Small Bodies display that included MUSES-CN, STARDUST, Deep Impact, Comet Nucleus Sample Return, Contour and NEAR.  The Discovery Program Office presented a poster on the its education and public outreach efforts, including STARDUST.  An article in the Times-Star, titled "NASA/JPL Stardust Mission Training" and authored by a participant in the JPL Ambassadors Program, described the positive educational experiences gained from a recent web-chat training session with STARDUST.
 
For more information on the STARDUST mission – the first ever comet sample return mission – please visit the STARDUST home page:
 
http://stardust.jpl.nasa.gov