October 18, 1998
- Operational power for the Clouds and the Earth's Radiant Energy System (CERES) Proto-Flight Model (PFM)
instrument aboard the Tropical Rainfall Measuring Mission (TRMM) spacecraft was removed at approximately
5:00 AM EDT October 18, 1998. A TRMM telemetry monitor designed to place CERES in the safe mode (elevation
head stowed, azimuth brake applied) and remove operational power was triggered after the Data Acquisition
Assembly (DAA) +15 Volt converter exceeded a predefined limit of 18.0 Volts. The 18.0-Volt limit was chosen
in order to provide operating margins for components downstream of the voltage converter.
- This action occurred after approximately 4.5 days of instrument operations in various modes designed to
collect data for engineering assessments. This operational time provided valuable data that will be used by
the CERES Tiger Team in determining the status of the voltage converter (degradation rates and sensitivity)
and will aid in planning for future operations to restore the instrument to a science operations mode.
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