Monthly Newsletter

March 2001

installed on beam line II and started calibration on March 29.

XPS Status
The XPS is essentially 100% complete. Additional environmental and EMI-EMC testing has been completed and previous PFR's (problem failure report) items have been successfully resolved. A picture is worth a thousand words, so...

XPS Assembly
Mass: 2.25 kg
Power: 3.4 W
Size: 18.7 cm x 17.6 cm x 15.6 cm

SORCE Data System Status
Most long term database code is now written and being tested, capabilities to utilize command and telemetry database are being added. Ancillary services development continues, spacecraft orbit services are 95% complete, interpolation, integration, spline algorithms and operators to propagate uncertainties have been added to the math utilities, and the astronomy library is still 90% complete. Spacecraft attitude server multimission design pattern and code is in place and generic attitude processing algorithms are implemented. Attitude telemetry information from Orbital has been received and is now being examined. When orbit services are complete, SORCE specific attitude software development will begin. General science algorithms have seen progress in wavelength determination/ calibration and aperture area calibration. SOLSTICE science processing development has been made in dark correction, dead time correction, responsivity calibration access and responsivity determination algorithm. Monthly telecons with ESDIS are ongoing, the next scheduled for April 19. A schedule to drive development and testing of interfaces between ESDIS and SORCE is underway.

Microprocessor Unit & Flight Software Status MU Status
The flight MU is 33% complete. The MU PCI I/O board SSI command FPGA design has been fully tested as well as the telemetry design. The flight board is out for assembly and the completed board should be in house by early April. Fabrication of the GCI flight PCB has started at SEAKR, an outside vendor, with most work complete on SOLSTICE. SIM and TIM boards have just begun.

MU Flight Software
PCI I/O hardware integration is complete in the PCI target, SRAM and EEPROM, GCI command and GCI telemetry. A/D converter build is underway. GCI software driver and 1553 software driver and sequencing engine are complete. The XPS control task in complete, the TIM control task begun. Additional staff has been added for the SOLSTICE and SIM control tasks. Two additional CTSIMS should arrive any day and they will increase testing capabilities.

Spacecraft Systems
SORCE staff will visit the Chandler, Arizona Pegasus rocket facility April 4-5. Particular interest will be focused on payload models, fit check, and stage 3 camera mountings and camera operation. A new southerly launch trajectory has been chosen for SORCE. The casualty expectation is considered almost nil and ground asset availability requirements have been met with the incorporation of a U.S. Navy ground station in Overberg, South Africa. All SORCE mass models have been delivered to Orbital. Integration and test preparations include the delivery and fabrication of mechanical and electrical ground support equipment such as: Flotron stand, delivery of cradle materials, frame for rack mount equipment, finished cable designs, uninterruptable power supply and meters. Preliminary FMEA's (failure modes and effects analysis) have been delivered for SOLSTICE, SIM, TIM, MU and XPS. FMEA reviews and redlines are in process. Power, mass, memory and bandwidth margins continue to be in good shape.

Orbital News
Orbital completed the instrument bench doubler repair analysis and briefed GSFC, but since the bench must be entirely rebuilt due to substandard composite material present in the original bench, the study will only be utilized for future trouble shooting. The SORCE "gyroless" study is complete and a stop work order for FOG (fiber optic gyro) production is in process. The Solar Cell CDR (critical design review) was completed with Spectrolab, and there are no outstanding issues resulting from the review. Flight cards for the PRE (power system) have been received and 25 more are expected before the end of March. Additional test equipment dedicated to the SORCE project was delivered to Orbital and some work has been outsourced to improve the schedule. Overtime has also been scheduled. The late delivery of the Alenia transceiver has caused workarounds, and Alenia management will be visiting Orbital April 4, and the issue will be addressed, again. FSS (fine sun sensor) light cell board assembly is complete and awaiting engineering model shock test. APE EDU late delivery due to a lingering FPGA problem has been addressed with the addition of extra design staff.

Information Submission:
Each month SNS will present mission progress, highlights, and news. If you have any information to distribute to the SORCE Team, contact, and we will include it in the next month's issue of SNS.
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