ACE Weekly 10/24/03 - 10/30/03 All ACE spacecraft subsystems are performing nominally. An attitude maneuver was successfully executed on 10/24/03. The next attitude maneuver is scheduled for 11/06/03. Recent solar activity has had some effect on the ACE spacecraft. Normally the ACE Spacecraft experiences a 2% drop in solar array output over a year's time, however the recent solar activity has dropped the solar array output an additional 1% in one week's time. (This is an expected result based on past experience with increased solar activity.) The ACE spacecraft utilizes only 50% of the solar array power available so this 1% degradation is negligible. In addition some instruments are experiencing some limit violations and increased activity. The FOT is monitoring all instruments and notifying instrumenters of any and all unexpected events. ============================================================================ Orbit Events: The next SEV transit will occur November 26th through December 20th. The minimum SEV angle expected will be approximately 1.19 degrees. ===================================================================== OCRs Executed: OCR SWPX-036 was scheduled for execution on DOY 03301 (10/28/03) but was delayed by Jim Griffee because of the solar activity. It is now scheduled for execution on DOY 03308 (11/04/03). ===================================================================== Ongoing Activities: TAPS: The FOT is currently testing Release 4.1.8 to ensure all DRs flagged as "essential to transition" have been fixed. The next release 4.1.9 is schedule for delivery on 11/04/03. ---------------------------------------------------------------------------- Automation (ROBOTT): - ROBOTT version 0.2 (Offline) is operational on String 1. - The next release of Offline and HSM has been pushed back to November 5th to allow for more DRs to be included in the release and to allow for further testing of those DR fixes on String 3. - Command & Control is still being tested by the Automation team with not much progress due to WIND/POLAR having some problems this week. - The first draft of the SUG is expected soon. ===================================================================== Anomalies: DOY 03297 (10/24/2003) ACE Anomaly G03-0107 - GDS 26m (DSS-16) - Command Not Reaching Spacecraft ACE FOT noticed that the first command did not make it to the spacecraft, but were receiving command echoes from CPA; Notified DSS-16 to monitor commands on their end. ACE FOT resent first command; no success. ACE FOT verified command mod index of 0.86 with DSS-16. ACE FOT requested that DSS-16 manually reset the command modulation index to 0.86. ACE FOT resumed commanding and all commands made it to the spacecraft. IMPACT: Delayed pass activities for ~12 minutes. DR# G103565 DOY 03297 (10/24/2003) ACE Anomaly S03-0022 - Mnemonic S3DPU_CONV_SEC_I Limit Violation The mnemonic, S3DPU_CONV_SEC_I, violated its red high limit twenty times during the pass. Due to the length of the dog-leg maneuver, the S3DPU Idle Counter was not monitored. However, after the pass on DOY 298, all the data will be obtained for the S3DPU Idle Counter and S3DPU_CONV_SEC_I and passed on to Mark Popecki. M. Popecki responded that this was probably related to data processing due to the increased solar activity. Impacts: Unknown at this time. FOT to continue monitoring. DOY 03301 (10/28/2003) ACE Anomaly G03-0108 - GDS 26m (DSS-16) - TCP Halt DSS-16 notified FOT that the TCP required a reboot. Telemetry was offline from 15:57:08 to 16:00:10. IMPACT: Delayed pass activities. All data subsequently recovered. DR# G103580 DOY 03301 (10/28/2003) ACE Anomaly S03-0023 - Mnemonic STAR_FA_CNT Limit Violation. The mnemonic STAR_FA_CNT (star false alarm count) violated the red high limit of 128, 10 times throughout the pass. IMPACT: Unknown. There was severe solar activity at this time, but it is not known if this is what caused the violations. FOT still investigating. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Glen A. Miller ACE Flight Operations Observatory Engineer Honeywell Technology Solutions Inc. Goddard Space Flight Center Building 14, Room W10A Mail Stop 428.2 Greenbelt, MD 20771 Office: 301-286-7071 Pager: 800-425-3174 Fax: 301-286-1729 Email: gamiller@pop500.gsfc.nasa.gov ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~