ACE Weekly 02/20/04 - 02/26/04 All ACE spacecraft subsystems are performing nominally as ACE as begun it's SEV transit. An attitude maneuver was successfully executed on 02/23/04. An additional stationkeeping/attitude maneuver was successfully executed on 02/26/04. The next attitude maneuver is scheduled for 03/01/04. ============================================================================ Orbit Events: The current ACE transit began February 22 and ends March 15 (a span of 22.49 days). This transit 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 4.2 was delivered on 02/12/04 and is currently being tested by the FOT. Only minor problems have been found and are expected to be resolved with release 4.2.1 which is scheduled for installation on 02/27/04. - The latest SUG was released for review on 03/26/04. - Plans for transition from GTAS to TAPS are being discussed. ---------------------------------------------------------------------------- Automation (ROBOTT): - Release 0.4 (HSM & OFFLINE) is operational on String 1. - OFFLINE: Testing of the fixed DRs is progressing well. 3 DRs have been verified on String 3. - HSM: 2 DRs have been fixed on String 3; both have been verified. A third DR may be a part of the next release but has yet to be verified. - COMMAND&CONTROL: All 6 DRs for C&C have been fixed and have been verified on String 3. Some minor problems have been identified that must be fixed prior to the next release. - RTMON: There have been some minor problems encountered while testing the real-time monitor and the real-time tasks. Most of the problems involved tasks not being performed either by CRON or the "Start Real Time" button. Testing will continue with real-time monitor failover/reboot process. A true string failover test will not happen until the real-time monitor is moved over to String 2. - Testing of the next release and verification of all DRs apart of the next release should be finished by 3/1. It has tentatively been decided to install the next release on String 2 on 3/2. ============================================================================ Extra Spacecraft Activities: None ===================================================================== Anomalies: DOY 04054 (02/23/04) ACE Anomaly G04-0014 - GDS 34m (DSS-27) Delayed AOS/RNS Problems At 14:50, DSS-27 contacted the FOT to verify that telemetry was online. The FOT stated that telemetry was not online. At ~15:10, DSS-27 stated that the problem involved the Reliable Network Server (RNS) #1. RNS #1 had crashed, thus DSS-27 switched over to RNS #2. However, the FOT was still not receiving any telemetry at the MOC. At 15:40, D27 wanted to attempt to bring up another downlink channel and forward the Real-time telemetry to the MOC. The FOT gave approval for this task. At 15:45, telemetry was received at the MOC and nominal pass activities were started. IMPACT: AOS and the scheduled attitude maneuver were delayed by ~55 minutes. All telemetry was eventually recovered. DR#G104066 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~