ACE Weekly 01/23/03 - 01/29/04 All ACE spacecraft subsystems are performing nominally. An attitude maneuver was successfully executed on 01/28/04. The next attitude maneuver is scheduled to occur on 02/06/04. ============================================================================ Orbit Events: Per Craig Roberts (FDF): The next ACE transit begins February 22 and ends March 15 (a span of 22.49 days). This one will involve the closest angular approach to the Sun yet seen, i.e., 0.63 degree (deg) from solar center. (By comparison, the solar angular radius as seen from Earth at that epoch will be approx. 0.27 deg). The updated details and epochs (UTC) follow: 22 Feb 05:22 4.75 deg inbound 28 Feb 15:51 2.0 deg inbound 1 Mar 17:19 1.19 deg inbound 3 Mar 21:57 0.63 deg closest approach 6 Mar 13:40 1.19 deg outbound 8 Mar 17:55 2.0 deg outbound 15 Mar 16:14 4.75 deg outbound The 1.19 deg reference was included because that was the closest approach during the December transit. ACE will spend 4.85 days within the 1.19 deg zone. ===================================================================== OCRs Executed: None. ===================================================================== Ongoing Activities: TAPS: Release 4.1.13 was delivered on 01/06/04 and is currently being tested by the FOT. Open DRs have been prioritized by the FOT in preparation for transition. The next two releases 4.2 and 4.2.1 are scheduled for 02/11/04 and 03/03/04 respectively. Upon delivery of Release 4.2, TAPS should contain all functionality required to allow for TAPS transition. ---------------------------------------------------------------------------- Automation (ROBOTT): - Release 0.4 (HSM & OFFLINE) was installed on String 1 on 01/21/04. The Command & Control component was not delivered because it is NOT ready for operational use. - All DRs for Release 0.4 have been tested on String 1 and on 1/29/04 the FOT moved operations back to String 1. - FOT will begin testing next week on String 3 for C&C and the real-time monitor. ===================================================================== Anomalies: DOY 04027 (01/27/04) ACE Anomaly S04-0002 - Mnemonic STAR_BKGD Red High Limit Violation The mnemonic STAR_BKGD ( Star Scanner Background High Flag) violated the Red High limit of 20, one time during the pass at 17:48:04. The mnemonic came back within limits at 17:48:36. IMPACT: None. The STAR_BKGD has been going over 20 (red high limit) for at least the past year. But this is the first time we've observed 2 consecutive values out-of-limits during a pass. STAR_BKGD is slowly increasing as one would expect after 6 years on-orbit. The STAR_FA_CNT (Star Scanner False Alarm Count) is still less than 30. No other problems have been found. The FOT will continue to monitor the star scanner. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~