ACE Weekly 09/20/2011 - 09/26/2011 SWICS is in the same state as of last week (9/19/2011) and collecting partial science data. All ACE spacecraft subsystems are performing as expected. ======================================================================== Orbit/Attitude: Type Attitude Date 09/21/2011 DOY 264 2011 Thrusters 2R 4R+ 4R- Duration 15:38 min Start 13:45:14z Stop 14:00:52z HGAStart -7.79deg HGAStop +7.61deg SunStart 17.81deg SunStop 5.64deg SpinStart 5.0146rpm SpinStop 5.0186rpm Nutation 0.20deg Firing 79 pulses FuelUsed 0.2492lbs FuelRemain 126.7820lbs FinalSCMass 1361.042lbs The next attitude maneuver is scheduled for Friday 10/07/2011. ======================================================================= OCRs: No SWICS commanding performed this week. SWICS remains in ESA-energy only mode with the MCP voltages off. This bypasses the TOF system and collects partial science data. (MCP=MicroChannel Plate, ESA=ElectroStatic Analyzer, TOF=Time-Of-Flight). ======================================================================== Activities: Data Capture: 99.88% DOY 261-268 2011 264-06:14:54 - 264-06:15:48 55 sec DSN DCD problems 265-03:13:32 - 265-03:14:15 44 sec gap in redump 265-05:16:51 - 265-15:18:44 1 min 54 sec gap in redump 265-15:25:05 - 265-15:33:10 8 min 5 sec antenna problem - RT ACE is doing much better in data capture than originally expected. Not recording during passes saves ~15 minutes of antenna time each day (1.75 hours/week). We also scoured the DSN schedule after GRAIL launched and found 7 slivers of available antenna time, 35-55 minutes in duration. This provided 5.7 hours of antenna time over the first 3 weeks of GRAIL. ACE needs ~19 hours of antenna time per week. We're still behind in the SSR playback, but hope to catch up in October when GRAIL is not using so much antenna time. Mars Reconnaissance Orbiter (MRO) looked at the possibility of taking ACE's Friday pass (09/23/2011) to recover from safe-mode. We told MRO that we would not release the antenna time and that they would need to declare a spacecraft emergency to take it. Eventually, DSN Maintenance released their antenna time which allowed SOHO to move and give time to MRO. FDF Product Server Update FDF resolved 2 problems this week. 1) The ACE folder had been missing from the RIONet server (stewart) and is now there. 2) The folders were not visible on the bonham server are now visible with some (but not all) accounts. The Wallops Command and Data Acquisition (WCDA) ground station uses FDF INP files to provide ACE data to the NOAA Space Weather Prediction Center (SWPC). On Friday 09/23/2011, WCDA's account on the current FDF Product Server was terminated and WCDA was not able to track ACE. The FDF analyst emailed the INP files and WCDA tracking was restored that same day. INP files are generated every Monday. We are waiting to hear if WCDA has a working account on the new system. During Monday's solar activity, the ULEIS shutter autonomously closed to 6% between 0934z and 1341z. Exact times for shutter movement will be provided in next week's report when the recorded data has been downlinked. ======================================================================== Anomalies: DOY 264 09/21/2011 S-ACE-0627 G11-0053 DSN DCD Problems DSN's Data Capture and Delivery (DCD) system had a double storage failure. No telemetry was sent to the MMOC for the remainder of the ACE pass. The DCD system did save the data and was available after the pass. DR#N107619 Impact: There is a 55 second gap due to the playback not being cleanly terminated at the end of the pass (aka SSR stuck in playback). DOY 264 09/21/2011 S-ACE-0627 G11-0053 DSS-27 Antenna Tracking 20 minutes before End-Of-Track (EOT), the ground station had an "Antenna Drive Cabinet Comm Lost" alarm. Telemetry was restored in 8 minutes. Commanding to the spacecraft was not re-established. DR#G111980 Impact: Since the SSR was not in record, the 8 minutes of data loss is not recoverable.