ACE Weekly 08/09/02 - 08/15/02 All ACE spacecraft subsystems are performing nominally. An attitude maneuver was executed on 08/13/02. The next attitude maneuver is scheduled for 08/23/02. This is Paul Douglas' last week with ACE. The FOT would like to thank Paul for all his hard work over the years and wish him Good Luck at his new job. ============================================================================ OCRs Executed: None ============================================================================ Ongoing Activity: The engineering test to determine the new HGA constraint is continuing. The current constraint is 6.0 deg., with current tests reaching 6.5 degrees. The FOT has been monitoring the Signal Strength, the MFR AGC levels, and the Signal-to-Noise Ratios(SNR). The drop in RF levels from an HGA angle of 0 deg to 6 deg has been approximately 3dB. There has been no loss of telemetry due to the increased HGA angles. Analysis is ongoing to determine new HGA angle constraint. The following HGA angles and range values are from FDF. Man Date Pre Man Post Man Earth-ACE Range 03/28/02 -4.58 deg +4.38 1408287 km 04/04/02 -4.35 +4.50 1414808 04/11/01 -5.09 +3.79 1428491 04/18/02 -5.16 +3.85 1440512 04/26/02 -5.77 +5.56 1455949 05/06/02 -5.72 +5.43 1493008 05/17/02 -5.81 +5.31 1527979 05/28/02 -4.34 +4.88 1550263 06/06/02 -2.38 +5.96 1576064 06/20/02 -6.57 -3.66 1590405 06/26/02 -6.43 +5.94 1592458 07/12/02 -6.5 +6.5 1598879 07/30/02 -6.5 +6.5 1567441 08/13/02 -5.34 +6.43 1532343 ============================================================================ TPOCC Release 5.2 String 2 Testing Status Testing on String 2 is still in progress. No major discrepancies have been reported. Expected completion date is August 23, 2002. ============================================================================ Anomalies: DOY 02224 (08/12/2002)ACE Anomaly #G02-0092 TPOCC - Lost connection state with manager ac1fe1a lost connection with state manager at 13:19:27. At the time the FOT had been bringing up pages and generating a quick page. Telemetry and commanding unaffected. IMPACT: ac1fe1a unable to display telemetry pages. DOY 02224 (08/12/2002)ACE Anomaly #G02-0093 DSN - D27 Problems Received degraded telemetry throughout pass with D27. Station reported SUN RFI at the TGC. IMPACT: Not able to complete dumping of recorders. Next day's pass extended to accommodate additional recorder dumps. DR# G101495 DOY 02224 (08/12/2002)ACE Anomaly #G02-0094 DSN - No Monitor Block Data At 13:54:44 monitor blocks went offline. D27 informed us that the Complex Supervisor software had died. The station restored monitor block data at 14:23. IMPACT: Loss of monitor block for ~ 30 minutes. DR# G101493 DOY 02224 (08/12/2002)ACE Anomaly #G02-0095 DSN - Antenna problems At 14:06:50 telemetry went offline. D27 reported the antenna lost pointing due to the Complex Supervisor software being down. IMPACT: No telemetry for 50 minutes. The data was recovered during the next day's support. DR# G101494 DOY 02227 (08/15/2002)ACE Anomaly #G02-0096 DSN - Incorrect Modulation Index After the first three commands of the day were sent to the spacecraft, the RCVR AGC's dropped significantly. The station reset the mod index and commanding was nominal thereafter. IMPACT: Yellow Low limit violations on RCVR_B_AGC. All commands sent were verified. DR# G101507 DOY 02227 (08/15/2002)ACE Anomaly #G02-0097 DSN - Tlm Loss/Bad TCA at D27 At 16:06:36 telemetry went offline, while the FOT was sending the LOS TTBin Load to the spacecraft. Telemetry came back online at 16:07:02 and the cmd was retransmitted and verified. At 16:23:48 the FOT started to see VC2 sequence errors. D27 reacquired the receivers to restore telemetry. For the degraded telemetry D27 swapped the TCA to Ch 2 and performed a hard reset of Ch 1. Telemetry improved at 16:28:33. IMPACT: LOS TTBin Load needed to be retransmitted. Approximately 9 minutes of telemetry loss was all recovered later in the pass. DR# G101506 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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 Fax: 301-286-1729 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~