Monthly Newsletter

October 2001

SORCE October 2001 Project Summary
The EOS SORCE Mission experienced noteworthy progress in all areas during the month of October 2001. The SORCE Mission is still on schedule and within budget. A launch date of July 31, 2002 is anticipated. At present all LASP and Orbital SORCE schedules are success oriented. Further hindrances, (i.e. the unforeseen replacement of inferior diodes and power converters) to current schedules could impact launch date. However, if the October 2001 work pace is sustained and instrument calibration, test and integration go smoothly, the SORCE Mission schedule may be maintained. As always SORCE plans are reviewed and adjusted on a daily basis to meet program needs.
SORCE System Status
The SORCE MIWG (Mission Integration Working Group) was held at KSC (Kennedy Space Center) October 23-24, 2001. A SORCE TIM (Technical Interchange Meeting) was held October 1, 2001. During the MIWG and the SORCE TIM the SORCE Pegasus rocket was evaluated, and SORCE "gyroless" flight status finalized. The SORCE rocket fairing passed electronic inspection and is considered flight suitable. Some minor problems were discovered on the SORCE rocket, however. Tie-bases in the aft skirt had debonded. Investigation is underway to determine the cause of the debonding. Inadequate surface abrasion prior to bonding and poor bonding material may have contributed to the problem. Tie-bases will be replaced and installed with a new process and adhesive. The Pegasus fin actuator system failed during thermal cycle. The probable cause was debris on the connector pins. The fin actuator systems will be inspected, retested and recertified. Fortunately, these processes present no schedule impact to the SORCE launch vehicle.
SORCE team members may attend the HESSI launch in mid-December 2001 and the GALEX launch in May 2001 in preparation for the SORCE launch. The next SORCE MIWG is scheduled at LASP in mid January 2002 to coincide with the SORCE IM (Instrument Module) Preship Review. SORCE power, mass and memory budgets remain healthy and confidence increases as more actual measured values replace the calculated values.
SORCE Instrument Status
XPS Instrument
The XPS instrument is complete and integrated on the SORCE IM (Instrument Module).

TIM Instrument
The TIM instrument build has been nearly complete for some time. Modifications to improve TIM performance are designed, built and incorporated on the instrument as they become evident. A case in point is the new semi-kinematic mounting base plates recently retrofit to the TIM instrument. In addition, TIM door position sensor slots have been lengthened to prevent overshoot when the door opens. The TIM door now senses its position properly. The four TIM door windows now possess superior seals, and the TIM instrument now holds a vacuum quite well. The PCB (Printed Circuit Board) thermistor has been moved to the rear wall of the TIM housing for improved performance.

TIM has logged over 500 hours of lab operation time and also has been integrated and run on the SORCE IM several times. TIM now has all flight electrical parts installed and successfully completed vibration on Nov. 6. Still remaining is the replacement of the vacuum door motor gearboxes with wet-lubed gearboxes.
TIM calibrations are well underway. Irradiance and power are being measured as well as possible. All available TIM cones are being measured for reflection. The calibrated gain as a function of temperature is also calculated. A solar simulator provides approximate solar intensity for measuring relative irradiance. "Absolute power" measurements are in progress by comparison to a trapped

Page 1