September 29, 1998
PROTO-FLIGHT MODEL CONVERTER TIGER TEAM CONTINUES INVESTIGATION --
- The Tiger Team examining the anomalous operation of the +15 volt converter on the Clouds and the Earth's
Radiant Energy System (CERES) instrument aboard the Tropical Rainfall Measuring Mission (TRMM) continues
its investigation. The anomaly exhibits characteristics that can be attributed to several potential causes.
Recently, following component testing and further data examination, the team has ruled out two potential
causes: radiation damage to the voltage converter components, and, a defective voltage monitor circuit.
Additional effort continues to assess potential failure mechanisms of the converter components that may
be attributed to mechanical and electrical attachment, premature part degradation, and/or thermal stress
- A high fidelity computerized model of the converter (PSPICE) will be developed to aid in understanding the
anomaly. This model will be developed by TRW and will later be enhanced by a separate corporation (STI) which
specializes in circuit modeling. Prior to STI's circuit model development, a non-disclosure agreement with
the voltage converter manufacturer will be required and is expected shortly after initiation of the STI task.
- In the interim, activity continues at TRW to determine the upper voltage operational limits on components
downstream of the converter, and to ascertain the thermal conditions in the vicinity of the converter.
These determinations will assist the Team in making a decision as to the proper conditions for re-powering
the instrument to gather additional diagnostic data.
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