ACE Weekly 01/02/2008 - 01/08/2008 All ACE spacecraft subsystems are performing nominally. ============================================================================ Orbit/Attitude: Type Attitude Date 01/07/2008 DOY 007 2008 Thrusters 2R 4R+ 4R- Duration 14:52 min Start 16:17:19z Stop 16:32:11z HGAStart -6.40deg HGAStop 7.35deg SunStart 9.47deg SunStop 8.91deg Nutation 0.26deg Firing 76 pulses FuelUsed 0.2464lbs FuelRemain 152.4504lbs FinalSCMass 1386.710lbs The next attitude maneuver and Station-Keeping #46 are scheduled for Thursday, 01/17/2008. ============================================================================ OCRs: None ============================================================================ Activities: The risk of data loss has increased for the December-January time frame. If there are problems with the passes, it may not be possible to acquire additional DSN time. Refer to 12/25/2007 weekly for further information. DSS-46 has had successful SLE passes since 12/31/2007. Next month (Thursday 02/07/2008 and Friday 02/08/2008), ACE will again have DSS-66 passes. ACE has only had one DSS-66 SLE pass (11/30/2007). We have asked DSN to forward any lessons learned from DSS-46 to DSS-66. ============================================================================ Anomalies: DOY 007 (01/07/2008) S-ACE-0261 (G08-0001) - ROBOTT Stopped ROBOTT cron stopped on DOY 006. ROBOTT has a known issue (CDSID#22925) that if a pass is near the DOY 006-007 day boundary, then ROBOTT stops taking passes starting on DOY 007. Unfortunately, this had not been incorporated into the ACE scheduling guidelines; the DOY 006 pass was 2015-2345z. Fortunately, the DOY 007 pass was a maneuver and the FOT discovered the problem before the pass had started. IMPACT: Manual intervention necessary to restart ROBOTT cron. DOY 007 (01/07/2008) S-ACE-0262 (G08-0002) - ROBOTT Incorrect Times Week 01 2008 starts with Monday 12/31/2007 (as expected). Starting with Week 02, ROBOTT has been misreading the schedule and has configured Command and Control for DOY 365 2008. Note, this is the first year where Week 01 included dates from the previous year since ROBOTT was started in 2004. IMPACT: On DOY 007 and DOY 008, ROBOTT/C&C was not working and the passes were taken manually. The cause of the problem was discovered on DOY 008 and a workaround has been implemented ... the local copy of the Week 01 schedule was modified and the 12/31/2007 pass deleted. Note, this problem will occur again in Week 02 2009. DOY 008 (01/08/2008) S-ACE-0263 (G08-0003) - ROBOTT C&C Failed After the DOY 365/Week 01 problem was solved, the FOT updated ROBOTT/C&C with the correct pass times. For unknown reasons, C&C did not execute the g_initial_contact procedure and crashed. IMPACT: The DOY 008 pass was taken manually.