ACE Weekly 04/02/2014 - 04/08/2014 All ACE spacecraft subsystems are performing as expected. ======================================================================== Orbit/Attitude: Type Attitude Date 04/08/2014 DOY 098 2014 Thrusters 2R 4R+ 4R- Duration 9:53 min Start 20:24:13z Stop 20:34:06z HGAStart -8.34 deg HGAStop +8.75 deg SunStart 12.32 deg SunStop 12.79 deg SpinStart 4.9886 rpm SpinStop 4.9907 rpm Nutation 0.18 deg Firing 50 pulses FuelUsed 0.1585 lbm FuelRemain 107.7584 lbm FinalSCMass 1342.018 lbm The next attitude maneuver is scheduled for Tuesday 04/15/2014. A summer campaign to increase the spacecraft sun angle will start next week. More information will be included in next week's report. ======================================================================== OCRs: None ======================================================================== Activities: Data Capture: 100% DOY 089-096 2014 ======================================================================== Anomalies: Update on Anomaly #G14-0005 (S-ACE-0677) DSS-15 Earth Receive Time (ERT) The DSN Earth Receive Time continues to have occasional problems after the spacecraft's data-rate change (from low-rate RTSW to high-rate). The problem is occurring in less than half of ACE's passes at Goldstone. 2014-071-21:14:12 DSS-15 ERT behind by 0.271 seconds 2014-082-20:54:40 DSS-24 ERT behind by 0.182 seconds 2014-084-20:15:34 DSS-15 ERT behind by 0.273 seconds 2014-089-16:36:28 DSS-15 ERT behind by 0.091 seconds 2014-092-16:20:13 DSS-15 ERT behind by 0.092 seconds 2014-096-15:39:21 DSS-15 ERT behind by 0.092 seconds 2014-098-20:02:22 DSS-24 ERT behind by 0.091 seconds DSN reports that this is an intermittent problem (DR# G114836/AR 118839) with the Receiver, Ranging, and Telemetry (RRT) software v11.3.6 that is currently undergoing soak testing. The ERT is behind by an integer multiple of telemetry frames (high-rate = 0.091 seconds per frame). DSN believes that halting and re-acquiring the TLP corrects the ERT. The clock reports sent to ASC and NOAA are not significantly impacted by the slight offsets. Updated clock reports have been sent to ASC. Note that one clock report (DOY 096) did result in the day boundary being rounded to a different second, which was manually rectified by ASC. The FOT has told DSN that this is not critical enough to stop the soak testing and that DSN can proceed with the halt/re-acquire TLP to correct the ERT.