ACE Weekly 06/03/2015 - 06/09/2015 All ACE spacecraft subsystems are performing as expected. ======================================================================== Orbit/Attitude: Type Attitude Date 06/09/2015 DOY 160 2015 Thrusters 2R 4R+ 4R- Duration 5:19 minutes Start 15:49:35z Stop 15:54:54z ra,decStart 76.73,38.91 ra,decStop 82.91,39.73 ra,decExpect 83.23,39.70 Deviation 0.24 deg (-4.7%) HGAStart -10.48 deg HGAStop +10.99 deg SunStart 16.07 deg SunStop 17.55 deg SpinStart 5.0129 rpm SpinStop 5.0141 rpm Nutation 0.07 deg Firing 27 pulses FuelUsed 0.0893 lbm FuelRemain 97.8835 lbm FinalSCMass 1332.144 lbm The next attitude maneuver is scheduled for Tuesday, 06/16/2015. ======================================================================== OCRs: None ======================================================================== Activities: Data Capture: 100% DOY 151-158 2015 ======================================================================== Anomalies: Update from last week's (5/27/2015 - 6/02/2015) reporting period: DOY 148 05/28/15 S-ACE-0704 Data Gaps during SSR Playback (DR# N109954) During the DSS-24 contact on DOY-148 (BOT=0000 UT, EOT=0230 UT), multiple instances of data gaps were identified during the SSR playback of ACE data. Consecutive data gaps in playback data with a duration as long as 4.4 min and as low as 2 seconds were observed during the contact (overall data gaps play back start: 147/16:01:56 (UT) and data gaps End time: 147/21:54:16 (UT)). Inspection of the ITOS event log indicates that (real-time) multiple occurrences of frame sequence errors (and skipped frames) were recorded during the 148:00:02:40.9 (UT) through 148:02:16:05.494 (UT) real time contact time frame. The ACE FOT has also confirmed that the data gaps are only present in the playback data (vc4) and not real time frames (vc1). Furthermore, the data gaps identified in the IDR data is consistent with the data gaps observed via inspection of the SLE files. The root cause of the anomaly is unknown at this time but DR# N109954 has been documented and the issue is under investigation. IMPACT: The net (playback) data captured for DOY 147 corresponds to 96.686% (that is, a data loss of 3.314% or 47.717 minutes). With the goal of confirming that the DOY 147/148 SLE file playback data gaps matched the results identified with the IDR data, the FOT retrieved the IDR files from DSN on 6/5/2015, and using the M-MOC tools confirmed that the data gaps are equivalent for the two data products (i.e., the % of gaps and the actual times of the gaps matched exactly).