ACE Weekly 08/06/04 - 08/12/04 All ACE spacecraft subsystems are performing nominally. An attitude maneuver was successfully executed on 08/12/04. 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. - All of the DRs fixed in ROBOTT v0.7 have been tested, 23 have been verified, 2 have been cancelled and 2 have failed (DR CDSID 20858 and DR CDSID 20870). 28 new DRs have been written against v0.7. - 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. Testing of v0.8 by the FOT will begin 08/13/04. ============================================================================ Extra Spacecraft Activities: None ===================================================================== Anomalies: DOY 04219 (08/06/04) ACE Anomaly G04-0089 - TAPS - Dropped Frames While reviewing short term data is was noticed that TAPS drops data every 7 minutes 9 seconds. In addition, further investigation revealed that TAPS drops 3 frames of data for every bad VC2 when it should only drop 2 frames. IMPACT: Lost trending data. DR to be submitted. DOY 04220 (08/07/04) ACE Anomaly G04-0090 - ROBOTT - Software Reboot At 13:02:47, during the procedure G_INITIAL_CONTACT, telemetry dropped out from DSS-16. Within five seconds telemetry was back online but G_INITIAL_CONTACT had stopped at the WAIT which checks to ensure the spacecraft receivers are in lock. C&C had paused commanding. The FOT waited to see if C&C would resume commanding but it didn't. Finally, after several minutes the FOT entered a "go" to resume commanding. G_INITIAL_CONTACT completed without any further problems. However at 13:50:30, ROBOTT rebooted and came back up on String 1. During that reboot DSS-16 experienced a telemetry dropout from 13:58 - 14:01 (DR#G104691). At 14:00, everything was back up. IMPACT: Delay in daily pass activities. DR CDSID 00021024, DR# G104691 DOY 04219 (08/06/04) ACE Anomaly G04-0091 - GDS (DSS-16) TCP Reboot The Reed-Solomon decoder at DSS-16 continues to show excessive corrections. During the pass with DSS-16 the FOT asked the station to swap from TCP1 to TCP2. After swapping TCPs, the corrections ceased. IMPACT: None DOY 04221 (08/08/04) ACE Anomaly G04-0092 - ROBOTT - C&C Paused Commanding At 13:41:33, telemetry paused for a few seconds and then resumed. However, C&C paused commanding and never resumed. IMPACT: Procedure S_OPS_PLBK_COMPLETE was not performed. SSR Failover was not enabled. Procedure G_END_DAY was not performed. AOS Timetag bins were not loaded which resulted in a low rate acquisition on next day's pass. DOY 04222 (08/09/04) ACE Anomaly G04-0093 - ROBOTT - C&C Did Not Resume Soon after g_initial_contact started, a telemetry drop occurred which paused C&C. Telemetry was back online in the same second, but C&C did not resume itself. FOT intervention was needed to resume C&C, but the procedure did not continue. C&C never issued the "go" directive at the hard wait. FOT intervention was needed again to enter a "go". IMPACT: Without FOT intervention, the system would have been "Paused" for the entire pass. This is similar to other known problems and DR CDSID 21024 and 20995 were already open for this. DOY 04223 (08/10/04) ACE Anomaly G04-0094 - ROBOTT - C&C Froze Due to TimeOutCC Rule The FOT attempted a test to see what would happen if C&C tried to add CC privileges when ac1xt3 had the privileges. Once C&C detected that CC privileges failed to be added, the TimeOutCC rule started firing on and off. This cause a loop in this rule and the whole C&C system froze. The test was done after all commanding had completed, but the FOT had to run g_acedown manually. DOY 04223 (08/10/04) ACE Anomaly G04-0095 - GDS 34m (DSS-24) APC Interface Lost DSS-24 lost the interface to the Antenna Pointing Controller (APC). This caused a 50 minute telemetry outage and 62 minutes of command loss. IMPACT: Delayed pass activities, loss of command capability. DR# G104698 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~