ACE Weekly 08/02/02 - 08/08/02 All ACE spacecraft subsystems are performing nominally. No maneuvers were executed this week. The next attitude maneuver is scheduled for 08/13/02. ============================================================================ OCRs Executed: SWPX-035, DOY 02218, 1614UT - Compensate for gain loss over the past 10 months. The SWEPAM team will need to monitor the realtime data during commanding to verify that the increased high voltage level does not cause excessive counts. ============================================================================ 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. Once all analysis has been completed, the new HGA constraint will be determined. 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 ============================================================================ TPOCC Release 5.2 String 2 Testing Status Testing on String 2 is still in progress. Expected completion date is August 19, 2002. ============================================================================ 26m Automation Demo Status An additional test was supported on August 2nd. The FOT has submitted the test results and are awaiting DSN's r`esponse to the discrepancies reported. ============================================================================ Anomalies: DOY 02217 (08/05/2002)ACE Anomaly #G02-0089 DSN - Delayed AOS Station failed to bring telemetry online at scheduled BOT of 1255UT. Station reported having receiver problems. At ~ 1305UT the station reported that they had the wrong exciter frequency selected. IMPACT: AOS was delayed by ~ 23 minutes however all data was recovered. DOY 02217 (08/05/2002)ACE Anomaly #G02-0089 DSN TGC Backup Channel Put Online At 1605UT telemetry ceased flowing into the MOC. The station brought the TGC backup channel online to correct the problem. Telemetry was restored at 1609UT, and no further problems were encountered. IMPACT: Unable to get a complete autonomy dump causing TPOCC to register false miscompares with the Ground Reference Image (GRI). DOY 02220 (08/08/2002)ACE Anomaly #G02-0091 DSN - Station AGC Level Very Low At approximately 1550UT, the MOC observed that station receiver AGC levels were dropping rapidly, reaching -130 dB/mW by 1551UT. By ~ 1623UT, the level had fallen to -140 dB/mW. The station was unable to correct the problem in R/T. IMPACT: End of day activities could not be performed due to low AGC levels which introduced too much risk for further commanding. ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ 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 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~