ACE Weekly 08/13/04 - 08/19/04 All ACE spacecraft subsystems are performing nominally. No attitude maneuver was executed this reporting period. The next stationkeeping /attitude maneuver is scheduled for 08/20/04. ============================================================================ Orbit Events: From Craig Roberts (FDF): The next ACE stationkeeping maneuver (SK-33) is scheduled for 08/20/04, to coincide with a scheduled attitude reorientation maneuver. Thus SK-33 will be out of the way just as the next SEZ transit--which will have its closest approach to the Sun on 08/30/04 --is beginning. The delta-V for 08/20/04 is currently projected to be about 0.37 m/sec in the anti-Sunward direction. The burn duration is estimated at 64 seconds. ACE's Lissajous orbit has now transitioned to an opening pattern, so the ACE motion will now be counterclockwise about L1 (and for that matter, the Sun) for quite a long time to come. ===================================================================== OCRs Executed: None ===================================================================== Ongoing Activities: TAPS: - Installation of TAPS release 4.3 is occurred on 07/20/04. FOT testing of this release is ongoing. -- Of the 6 DRs fixed in release 4.3, 5 have been verified, 1 has failed. - Additional DRs will be submitted for newly found problems. ---------------------------------------------------------------------------- Automation (ROBOTT): - ROBOTT v0.7 has been used for daily operations on String 1 since Tuesday 07/27/2004 (OCR GND-140) with ROBOTT in Advisory and Auto modes. No data loss or command problems due to ROBOTT have occurred this week. - ROBOTT v0.8 was installed on Strings 2 and 3 on 08/12/04 (OCR GND_141). The installation on both strings facilitates testing the RTMON component. Out of 25 DRs, 14 have been verified, 2 have failed, and the rest will have to be tested with v0.81. - ROBOTT v0.81 is scheduled for installation on Strings 2 and 3 on 08/20/04 (OCR GND_142) after the stationkeeping/attitude maneuver. This version contains a patch to C&C based on the discrepancies found during testing of v0.8. ============================================================================ Extra Spacecraft Activities: None ===================================================================== Anomalies: DOY 04228 (08/15/04) ACE Anomaly G04-0096 - ROBOTT - C&C Did Not Add MC Privileges At 12:13:01.2 C&C issued: ACC ADD MC; FOT noticed that the MC privileges were not added to C&C. IMPACT: FOT intervention was required to allow C&C to run for the entire pass. If FOT had not intervened C&C would have not ran G_ACE_UP or any other procedure. DOY 04229 (08/16/04) ACE Anomaly G04-0097 - GDS 26m (DSS-16) Telemetry Outage At 15:12:34, telemetry was lost from DSS-16. Telemetry resumed at 15:14:36. IMPACT: None. Data retrieved from SSR playback and CDR file. DOY 04229 (08/16/04) ACE Anomaly G04-0098 - ROBOTT - C&C Froze At 15:17, after a 2 minute telemetry outage, C&C attempted to resume itself without the forward link enabled. However, DSS-16 lost lock on the spacecraft receivers. C&C froze and minutes later at 15:27:55, the C&C flag (CF=5) was set to 5. At 15:33:42, the pop-up box was received that stated, "Failover (Reboot) In Progress". At 15:35:50, after the reboot, C&C started coming up before TPOCC. This caused the FOT to receive another pop-up box that stated, "Failover (String) In Progress. The failover was set to remain on string 1. Everything came back up without any problems. However, it was noticed that CRON was killed at 11:34:09 and not restarted. Again at 11:51:40 Cron was killed and not restarted. IMPACT: Loss of command capability. CRON was killed and not restarted (known DR). All telemetry retrieved via playback and CDR. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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 gamiller@pop500.gsfc.nasa.gov ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~