ACE Weekly 04/11/03 - 04/17/03 All ACE spacecraft subsystems are performing nominally. An dog-leg attitude maneuver was performed successfully on 04/14/03. The next attitude maneuver is scheduled for 04/25/03. ============================================================================ Orbit Events: The next expected SEV transit is to occur: Entry: 06/01/03 at 1442Z Minimum angle: 2.18 degrees on 06/13/03 at 1618Z Exit: 06/25/03 at 1652Z ============================================================================ OCRs Executed: NONE ============================================================================ Ongoing Activities: TAPS: Trending, Analysis and Plotting System (TAPS) development continues with emphasis being placed on fixing the DRs attributed to the current release. Testing is progressing on both TAPS#1 and TAPS#2. ---------------------------------------------------------------------------- Automation (ROBOTT): Offline and HSM are scheduled to be moved to String 2 on April 15th. Command and Control is still being tested by the Automation team. Date for release to FOT for testing is still TBD. Testing will soon begin with the receiving 0158 Monitor data into the GENSAA Data Server (GDS). Assuming all stations send the 0158 monitor data to the MOC, testing should be complete by next week. ============================================================================ Anomalies: DOY 03102 (04/12/2003) - ACE Anomaly Report #G03-0027 DSN 34m (DSS-27) Delayed Commanding Station 27 had troubles getting and maintaining lock on the spacecraft at the beginning of track. Numerous resweeps of the spacecraft had to be performed. Data was not online until 14:55 (14:50 pass start) and commanding was delayed until 15:48 (58 minutes after pass start). IMPACT: Delayed pass activities. All lost data was recovered on next day's pass. Additional commands needed to be sent to configure spacecraft back into the high data rate. The inability to command inhibited the FOT from disabling an onboard timetag bin which executed and put the spacecraft back into the low data rate. DR# G102630 DOY 03104 (04/14/2003) - ACE Anomaly Report #G03-0028 DSN 34m (DSS-27) SFG Problems Prior to pass start the SFG1 connection was lost. Station operator was unable to log into SFG1 to start application. Reboot from machine itself still did not connect. Swapped to SFG2. Still not a complete interface. Station operator discovered CISCO switch port for SFGs was in DISABLE state. RE-enabled the port and switched back to SFG1. Data resumed and commanding enabled. IMPACT: Unable to command for 130 minutes delaying planned spacecraft maneuver. Pass had to be extended in order to execute spacecraft maneuvers. All data was recovered. DR# N100953 DOY 03105 (04/15/2003) - ACE Anomaly Report #G03-0029 DSN 34m (DSS-27) Unstable VCOs / Wrong U/L Freq At 15:00, the FOT requested DSS-27 to change their uplink frequency to 2098.006 (incorrectly using 2097.99 mHz) and resweep for the uplink. The FOT also informed the station of VC2 hits and high VCOs. At 15:07, DSS-27 confirmed changing the uplink frequency to 2098.006 and bringing down their carrier. At 15:10, DSS-27 gave the FOT a go for command. The FOT immediately noticed good VCOs and the VC2 hits stopped. A DR was requested due to the wrong uplink frequency being used by DSS-27. At 15:24, the FOT started receiving VC2 hits again and informed DSS-27. DSS-27 stated everything appeared fine on their end. JPL was informed and confirmed seeing the degraded data. IMPACT: Delayed pass activities. All data was recovered. DR# G102647 DOY 03105 (04/15/2003) - ACE Anomaly Report #G03-0030 DSN 34m (DSS-27) Telemetry Outage / SFG Problems At 17:03, DSN Monitor and telemetry data dropped out. The FOT called JPL Comm several times but didn't get an answer. The Ops Chief was called and informed of the telemetry loss. The Ops Chief informed the FOT that they are seeing several alarms, some stating the SFG is full. At 17:20, telemetry was back online. IMPACT: Delayed pass activities. All data was recovered. DR# N100958 DOY 03105 (04/15/2003) - ACE Anomaly Report #G03-0031 DSN 34m (DSS-27) Bad Ground Receipt Time Earth Receipt Time off by -0.054 msec for entire pass. There's an OPD at DSN for them to reboot the TCA before each pass . . . but this is the 3rd support with bad time-tags within the past month. 076 DSS-27 -0.073 entire pass 091 DSS-27 -0.020 entire pass 105 DSS-27 -0.054 entire pass IMPACT: The incorrect time-tags generate incorrect calibrations of the spacecraft clock (done daily, using 2 days worth of data). The scientists decided to disregard the incorrect calibration and instead extrapolated the calibration from DOY 104. DR REQUESTED DOY 03107 (04/17/2003) - ACE Anomaly Report #G03-0032 DSN 34m (DSS-54) Telemetry Dropout At 16:27:49 telemetry went off line. Notified DSS-54 that we were no longer receiving telemetry. DSS-54 switched from TCA channel 1 to TCA channel 2. At 16:31:21 telemetry came back on line. IMPACT: None. All data was recovered. DR# M101543 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Glen A. Miller Honeywell Technology Solutions Inc. ACE Flight Operations Team 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 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~