ACE Weekly 05/07/2008 - 05/13/2008 All ACE spacecraft subsystems are performing nominally. ============================================================================ Orbit/Attitude: No maneuvers were completed this week. The next attitude maneuver and Station-Keeping #48 are scheduled for Tuesday 05/20/2008. =========================================================================== OCRs: None ============================================================================ Activities: The discussion and investigation continues as to why telemetry was not received at GSFC for the DSN passes on 5/3/2008-5/5/2008 (DOY 124-126) and other network problems. ============================================================================ Anomalies: DOY 128 05/07/2008 S-ACE-0317 G08-0056 ROBOTT/C&C Failed The MOC automation software (C&C) failed to execute the initial commanding procedure (g_initial_contact). Since SSR playback was behind schedule and DSN time was limited, it was decided to execute the pass manually. This problem last occurred on 01/08/2008 (AR#G08-0003) IMPACT: The DOY 128 pass was taken manually. DOY 131 05/10/2008 S-ACE-0318 S08-0002 Increase in SBE_CT_B SSR B Single Bit Error Count (SBE_CT_B) increased from 3999 to 4533 since last checked on DOY 123 (05/02/2008). SBE_CT is tracked as a measure of SSR health. This is the first time the SSR has provided the address where the Single Bit Error occurred (slice 253) IMPACT: Minimal. Single Bit Errors are automatically corrected by the SSR and occur infrequently. No non-correctable errors (Hard Single Bit Errors & Double Bit Errors) have occurred throughout the mission. SBE_CT_A SBE_CT_B 12/01/1999 15 09/06/2003 286 02/25/2003 30 09/22/2004 608 06/05/2003 270 11/15/2004 858 07/26/2007 510 11/07/2006 2118 01/12/2007 3125 06/21/2007 3238 04/26/2008 3999 05/10/2008 4533 (slice 253) DOY 134 05/13/2008 S-ACE-0319 G08-0056 Telemetry Not Received at GSFC A network problem caused only a few frames of telemetry data to reach the ACE MOC from DSS-27. JPL Comm and Goddard Comm Control were unable to resolve the problem. The MOC automation software (ROBOTT) is designed to command only when telemetry is online in order to perform state-of-health checks. Low-rate data recorded at DSN CDR. DR#N104858 IMPACT: SSR playback not started. SSR Failover will occur on DOY 135 at 1115z.