STARDUST Status Report

September 1, 2000

There were two Deep Space Network (DSN) tracking passes during the past week. All subsystems onboard the spacecraft are performing normally. During the last 2 passes using the Medium Gain Antenna (MGA) and Solid State Power Amplifier 1 (SSPA 1), power started off normally but dropped 2 dB during each pass. The SSPA's have been powered off between passes during the last year because this drop in gain would always occur when the SSPA's were left on for long periods of time after launch. This will be studied because of the potential for the SSPA's to not recover this loss of gain when powered off.

A Dust Flux Monitor (DFM) checkout test was successfully performed to verify the instrument would still provide more than thirty minutes of nominal operation. This was the first time the DFM had been powered on since September 1999. The DFM operated nominally for 36.5 minutes when it entered its noisy state and was then powered off. The noisy state is associated with an abrupt instrument operating change where there are rapid fluctuations in current. This test successfully verified that more than thirty minutes of nominal operation is still possible, sufficient to capture 95% of the expected Comet Wild 2 encounter science data.

After a few minutes DFM was powered on again for 1 minute to see if power cycling the DFM would reset the instrument to normal operations. Normal operations did not return after power cycling, therefore DFM is expected to only be powered on for 20 minutes at Earth flyby this coming January and at the Comet Wild 2 encounter in 2004.

The last two images of the Navigation Camera Charge Couple Device (CCD) heater test were taken. The pre-test, 1, 2, 4, 8 hour and part of the 16-hour image sets have now been transmitted to the ground. Next week, the remaining 32, 56, 100, 144, and 341 hour image sets will be transmitted.

The Cometary Interplanetary Dust Analyzer (CIDA) was power off and the flight processor clock speed was reduced to 10 MHz. These actions were taken to keep the Command and Data Handling (CDH) temperature below 43 degrees C. Flight experience has shown that Payload Attitude Control Interface (PACI) card resets occur when the CDH temperature is between 43-45 degrees C. As internal temperatures are rising to near this temperature range as the spacecraft comes closer to the Sun on its way to an Earth flyby in January, thermal analysis indicates that by powering off the CIDA and reducing the clock speed the CDH temperature will remain below 43 C.

Next October, CIDA will return to operation and the clock speed increased to 20 MHz, which will push the CDH temperature to above 45 C, thus keeping the temperature outside of the region where PACI resets occur.

For more information on the STARDUST mission - the first ever comet sample return mission - please visit the STARDUST home page: