Monthly Newsletter

November/December 2001

Happy Holidays

SORCE Mission Status November December 2001
Major SORCE Mission accomplishments during the month of November 2001 include the completion of the SOLSTICE instrument A/B SURF calibrations, SOLSTICE A/B shake, replacement of GCI (Generic Channel Interface) parts and the testing of the SORCE Integrated Instrument Module in the MOBI Thermal Vacuum Chamber. SORCE continues to closely monitor and adjust schedules for instrument fabrication to respond to changing priorities and facilities availability during fabrication and test. SORCE instrument delivery is now trailing the delivery of the SORCE spacecraft bus that is currently two months behind schedule. A potential launch delay may be requested.
SORCE System Status
The SORCE Integrated Thermal Analysis is complete. Preliminary SORCE IM Thermal Analysis results revealed some slightly unexpected results, but all readings are within operating parameters. In the area of SORCE contamination control initial pump rates from the IM (Instrument Module) in the LASP MOBI chamber indicated that the integrated IM is very clean. TQCM (Total Quartz Crystal Microbalance) have been used for the SORCE IM thermal vacuum test. TIM and SIM vibration tests have been done and retesting continues. Efforts to wrap up the SORCE RTM (Requirement Traceability Matrix) are underway. The SORCE Instrument Module flight harness has been wrapped and baked out.
The SORCE IM underwent a hardware stress/acceptance test in the LASP MOBI chamber. SORCE power, mass and memory budgets are now based on actual measured

values and retain healthy margins. The focus of the SORCE Electrical System during November has been the MU (Microprocessor Unit). The SORCE MU Engineering Model is functional and consists of an EM (Engineer


SORCE Instrument module harness (above)

SORCE Upgraded MOBI Vacuum Chamber (below)

Engineering Model) RAD6000 computer, an EM PCI/IO, and EM Power Card and an EM LVPC (Low Voltage Power Center). Currently, the flight model EM RAD 6000 computer is under repair and the power card needs further test. The flight MU has just finished thermal cycle test and anomalies are being resolved. The hardware versus software disposition is the principle focus of anomaly resolution. In addition, an inrush current transient occurs on the MU LVPC. The problem was traced to the Interpoint DC/DC power converters on the LVPC. A filter circuit was added on the power converter to correct the situation. Testing indicates that the transient has been eliminated. More test, characterization and qualification time is required. The MU GCI's have been repaired with replacement diodes:

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