ACE Weekly 05/24/2011 - 05/30/2011 All ACE spacecraft subsystems are performing nominally. ======================================================================== Orbit/Attitude: Type Attitude Date 05/26/2011 DOY 146 2011 Thrusters 2R 4R+ 4R- Duration 13:16 min Start 14:19:54z Stop 14:33:10z HGAStart -5.85deg HGAStop +7.44deg SunStart 6.28deg SunStop 10.49deg SpinStart 5.0898rpm SpinStop 5.0933rpm Nutation 0.10deg Firing 68 pulses FuelUsed 0.2146lbs FuelRemain 128.6844lbs FinalSCMass 1362.944lbs The next attitude maneuver is scheduled for Monday 06/06/2011. ======================================================================= OCRs: None ======================================================================== Activities: Data Capture: 99.99% DOY 142-149 2011 2 small 31 second gaps due to DSN power problems and automated on-board SSR failovers 31 seconds 144-12:40:06 - 12:40:36 AR#G11-0038 31 seconds 148-09:02:44 - 09:03:14 AR#G11-0040 Update on NOAA Space Weather Prediction Center tracking of ACE NOAA continues to have a gap in their space weather tracking due to the loss of the antenna at NICT (Japan). The gap has narrowed to 3 hours as the spacecraft position and earth tilt improve visibility at WCDA (Wallops) and DLR (Germany). The Near Earth Network (NEN) Alaska Satellite Facility (ASF) and the NOAA's Gilmore Creek Facility continue to investigate their ability to track ACE. FDF is expected to provide INP files for ASF and Gilmore Creek in a few days. ======================================================================== Anomalies: DOY 146 05/26/2011 S-ACE-0612 G11-0039 D27 Equipment Problems Problems with DSS-27's Global Control Engine resulted in loss of ground antenna control (1506z). The ground station rebooted their systems and telemetry returned (1550z). Uplink was re-established at 1558z. DR#G111602 IMPACT: 44 minute realtime data outage to NOAA Space Weather. SSR redump continued on the following support (30 minutes). DOY 147 05/27/2011 S-ACE-0613 G11-0040 D27 Power Outage The DSN ground station was experiencing a power outage at ACE's Beginning Of Track (1535z). Power was restored, telemetry was online at 1701z and the uplink established 1733z. With only 1.5 hours left in the pass, the DOY 146 redump was performed and the SSRs were not swapped. DR#G111615 IMPACT: No impact to NOAA Space Weather since the spacecraft remained in the low data rate during this time. SSR failover and 31 second data gap occurred on DOY 148. DOY 148 05/28/2011 S-ACE-0523 S10-0007 Increase in SBE_CT_B SSR B Single Bit Error Count (SBE_CT_B) increased from 7339 to 7918 since last checked on DOY 145 (05/25/2011). SBE_CT is tracked as a measure of SSR health. Note, SSR errors will now be tracked in a single anomaly report. IMPACT: Minimal. Single Bit Errors are automatically corrected by the SSR. No non-correctable errors (Hard Single Bit Errors & Double Bit Errors) have occurred throughout the mission. SBE_CT_A SBE_CT_B 1999 15 2000 2001 2002 2003 270 286 2004 858 2005 2006 2118 2007 510 3238 2008 4533 2009 525 6839 2010 780 7339 2011 7918