ACE Weekly 07/10/2012 - 07/16/2012 All ACE spacecraft subsystems are performing as expected. The SWEPAM-Electron overcount alarm stopped flagging when the noisy CEM (#2) was masked off. See OCRs below. ======================================================================== Orbit/Attitude: Type Attitude Date 07/12/2012 DOY 194 2012 Thrusters 2R 4R+ 4R- Duration 17:06 min Start 18:08:12z Stop 18:25:18z HGAStart -8.15deg HGAStop +7.75deg SunStart 5.74deg SunStop 14.85deg SpinStart 5.0588rpm SpinStop 5.0632rpm Nutation 0.08deg Firing 87 pulses FuelUsed 0.2627lbs FuelRemain 120.6628lbs FinalSCMass 1354.923lbs The next attitude maneuver is scheduled for Thursday 08/02/2012. ======================================================================= OCRs: DOY 193 (07/11/2012) 1823-1833z SWPE-044 SWEPAM-E v1.14 Code Dump As part of the analysis of the SWEPAM-E overcount alarm, a dump of the entire on-board executable image was performed. DOY 198 (07/16/2012) 1803-1804z SWPE-045 SWEPAM-E Mask CEM #2 Recent analysis shows that the SWEPAM-Electron Channel Electron Multiplier (CEM) #2 (of 0-6, SWEPAM-E has 7) has become noisy which was causing the overcount alarm to flag. That channel has been masked and the overcount alarm has stopped. The possibility of noisy Channel Electron Multipliers was planned for when the instrument was built. Background Information: The SWEPAM-E overcount alarm started flagging intermittently on 1/22/2012. The alarm was flagging ~45% of the time in April and May; and almost continuously since 6/1/2012. The overcount alarm causes the instrument's voltages to be reduced and results in little scientifically useful data. Cumulatively, the overcount alarm had flagged for 73.5 days over the past 6 months. Preliminary from the instrument team concerning CEM #2 data being zeroed out: "There will be holes in the measured distribution. The effect on the scientifically-useful pitch angle distribution will be variable, depending on the magnetic field orientation relative to the instrument FOV, but we should be able to observe well-resolved distributions most of the time." Which is significantly better than having the instrument in continuous overcount alarm. DOY 198 (07/16/2012) 1805-1806z SWPI-046 SWEPAM-I CEM Voltage increase The instrument team has increased the CEM voltage level on the SWEPAM-Ion instrument from 2 to 3 (max possible=15) to determine if this improves instrument performance. ======================================================================== Activities: Data Capture: 100% DOY 190-197 2012 During last week's solar activity, the ULEIS shutter autonomously closed and reopened Sat Jul 14 2012, DOY 196 15:21:12z closed to 25% Sat Jul 14 2012, DOY 196 17:27:04z closed to 6% Sun Jul 15 2012, DOY 197 07:23:20z opened to 25% Sun Jul 15 2012, DOY 197 09:46:16z opened to 100% ======================================================================== Anomalies: DOY 192 07/10/2012 S-ACE-0646 G12-0008 DSS-27 Red The ground station's UPS tripped off causing the station to lose power. After power was restored, the station had problems with the uplink equipment. The uplink was available 13 minutes before the end of the pass, but too late to perform any activities. DR# G112964 & G112965 IMPACT: No pass activities performed. Data was recovered on the following pass. No SSR failover since there was less than 43 hours between the pass on Monday (7/9) and Wednesday (7/11). NOAA SWPC was not impacted since the spacecraft remained in the RTSW format. DOY 194 07/12/2012 No SOAR generated DSS-27 Antenna pointing The ground station had antenna pointing problems (+350 mdeg offset) due to an azimuth encoder issue. There was no data loss and therefore no anomaly report generated. But the downlink signal strength was reduced from -121dBm to -137dBm before the pointing was adjusted. DR# G112990 DOY 196 07/14/2012 S-ACE-0523 S10-0007 Increase in SBE_CT_B SSR B Single Bit Error Count (SBE_CT_B) increased from 12864 to 13302 between 7/12/2012 and 7/14/2012. SBE_CT is tracked as a measure of SSR health. 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 10995 2012 13302