ACE Weekly 01/28/2015 - 02/04/2015 ACE spacecraft subsystems are performing as expected. This weekly report covers 8 days in order to include the maneuver. ======================================================================== Orbit/Attitude: Type Attitude Date 02/04/2015 DOY 035 2015 Thrusters 2R 4R+ 4R- Duration 7:54 min Start 15:49:53z Stop 15:57:47z ra,decStart 304.91,-11.11 ra,decStop 311.85,-10.91 ra,decExpect 312.67,-44347 Deviation 0.84 deg (-10% short) HGAStart -8.53 deg HGAStop +8.84 deg SunStart 13.54 deg SunStop 7.93 deg SpinStart 4.9999 rpm SpinStop 5.0004 rpm Nutation 0.27 deg Firing 40 pulses FuelUsed 0.1275 lbm FuelRemain 101.2344 lbm FinalSCMass 1335.494 lbm The maneuvers have been short of the target every ~3 months (last occurrence in Nov 2014). We believe that the nitrogen fills the internal lines as the fuel in the external lines is slowly used. When the nitrogen reaches the thrusters, it is expelled and the reduced pressure causes the fuel from the A tanks to backfill the B internal lines. The process repeats every ~3 months. Equilibrium will eventually set in when the excess nitrogen from the B tanks is expelled (matching the amount of nitrogen in the A tanks). Analysis is ongoing to determine if and when to close the B latch valves. The next attitude maneuver will be next week, but the date is uncertain due to upcoming DSCOVR launch and antenna availability. ======================================================================== OCRs: None ======================================================================== Activities: Data Capture: 100% DOY 025-032 2015 Santiago (Near Earth Network) continues their ranging tests while ACE is in the low downlink rate. The data will be used in preparing for the DSCOVR mission. More tests are scheduled for the coming week. 01/28/2015 DOY 028 1505-1616z 01/29/2015 DOY 029 1501-1613z 01/30/2015 DOY 030 1711-1811z The SSMO scheduling team continues to work on the schedule for the DSCOVR launch (expected 2/8/2015). MAVEN will be doing "Deep Dip 1" and has increased DSN coverage starting 2/10/2014. The risk of data loss is higher than usual for February. ======================================================================== Anomalies: DOY 034 02/03/2014 S-ACE-0622 G11-0049 ITOS processes not finishing Starting Tuesday 02/03/2014 (DOY 034), some processes started with the ITOS "system" directive were hung and not finishing. Some processes completed successfully (e.g. ace_create_s_dumplist, pass_summary, etc) and others did not (ace_data_fwd, ace_clock_report, moving files). The WIND ITOS context was not impacted. ITOS was restarted Wednesday (DOY 035). This problem last occurred on 10/24/2012 (DOY 298 2012). IMPACT: Empty clock report file sent to ASC on DOY 034 & 035; corrected files was resent on 2/4/2015 (DOY 035). No data forwarding to NOAA SWPC for ~1 hour on 2/4/2015. Other hung system processes had minimal impact.