ACE Weekly 11/28/2012 - 12/04/2012 All ACE spacecraft subsystems are performing as expected. ======================================================================== Orbit/Attitude: Type Attitude Date 12/04/2012 DOY 339 2012 Thrusters 2R 4R+ 4R- Duration 8:13 min Start 16:34:31z Stop 16:42:44z HGAStart -8.53deg HGAStop +9.02deg SunStart 13.05deg SunStop 18.25deg SpinStart 5.0720rpm SpinStop 5.0739rpm Nutation 0.15deg Firing 42 pulses FuelUsed 0.1353lbs FuelRemain 117.6192lbs FinalSCMass 1351.879lbs The next attitude maneuver is scheduled for Tuesday 12/11/2012. ======================================================================== OCRs: DOY 335 (11/30/2012) 2107-2114z SIS-050 6 cmds The SIS data was noisy after the attitude maneuver on 11/27/2012 when the sun angle was increased to 16.8 degrees (the instrument deck is warmer with larger sun angles). These commands disabled noisy M1B HV strip # 33 and raised the threshold on M1A HV strip # 31. There are a total of 512 strips in the M1 and M2 detectors in the two SIS telescopes. So far 41 strips have been disabled and 2 VLSI readout channels were not working at launch. DOY 338 (12/03/2012) 1846-1853z SIS-051 7 cmds The previous commanding didn't reduce the noisy data. Two more strips needed to be disabled: M1A GND #29 & M1A HV #42. Also M1A HV #42 had its threshold raised. This eliminated the noisy data. There are a total of 512 strips in the M1 and M2 detectors in the two SIS telescopes. So far 43 strips have been disabled and 2 VLSI readout channels were not working at launch. ======================================================================== Activities: Data Capture: 100% DOY 330-337 2012 ACE completed the third WS1 certification test on 11/30/2012. The ACE Mission Director approved operations with WS1. The first operational pass is Friday 12/7/2012. See below for a review of WS1 testing for the past year. Antenna time is limited from Sunday 12/9 to Friday 12/14. Playback will fall behind by 30-60 minutes (5-10 hours of science data). No data loss is expected. The reasons for limited antenna time are: * GRAIL viewperiod at DSN overlaps ACE (new moon) * LRO viewperiod at WS1 overlaps ACE (new moon) * DSN DSS-54 antenna down for repairs * Short northern hemisphere views (Goldstone & Madrid) during winter * Mission views overlapping in December and January (Mars,Voyager,etc) ======================================================================== Anomalies: DOY 335 11/30/2012 S-ACE-0656 G12-0017 D34 unable to connect to DCD1 At 2313z, DSN's Data Capture and Delivery (DCD2) experienced a hardware failure. DSS-34 was unable to connect to DCD1. No telemetry was delivered to the MMOC for the last hour of the pass (2313-0015z). No DSN DR issued. IMPACT: No data loss. But no data to NOAA SWPC for 1 hour. Final state-of-health checks and redumps performed on the following pass. Manual intervention required to clean up ITOS procedures. ======================================================================== Average Sun Angles With Weekly Attitude Maneuvers Dates Avg Sun Avg SEV Sun-SEV (indicates extra s/c tilt) ----------- ------- ------- ---------------------------------- 10/18-10/23 11.0deg 5.1deg 5.9deg 10/23-10/28 9.3deg 3.3deg 6.0deg 10/28-11/06 7.3deg 2.0deg 5.3deg 11/06-11/13 8.4deg 3.8deg 4.6deg 11/13-11/20 10.3deg 6.3deg 4.0deg 11/20-11/27 12.7deg 8.6deg 4.1deg 11/27-12/04 14.9deg 10.1deg 4.8deg The following is background information that will be included in each weekly report. The project has accepted the SWEPAM team proposal to keep the spacecraft at larger sun angles with weekly attitude maneuvers. The SWEPAM-Ion instrument has a series of channel electron multipliers (CEMs) and larger sun angles allows more responsive CEMs to measure the solar wind. The maximum sun angle follows the Sun-Earth-Vehicle angle (SEV). The SEV angle is determined by the size/shape of the orbit around L1. When the spacecraft antenna is pointed directly towards earth, the spacecraft's sun angle will be equal to the Sun-Earth-Vehicle angle. With weekly maneuvers, the sun angle can be kept 4-6deg more than the SEV angle. This results in the spacecraft antenna aspect angle being kept between 5 and 9 degrees and never pointing directly back at earth. For reference, the SWEPAM team prefers sun angles above 13 degrees. With the current size of the L1 orbit, the sun angle will be above 13 degrees for ~45% of the time. ======================================================================== The following is a timeline of the highlights of WS1 testing 2011/07/22 SSMO asks if WS1 can support ACE and WIND 2011/08/04 NEN RF link calc reports WS1 can support ACE, but not WIND 2011/10 WS1 successfully receives ACE low-rate data 2011/11/21 WS1 successfully receives ACE high-rate data 2012/01/27 WS1 sends ACE data to the MMOC 2012/03/01 Uplink test - ACE RCVR A locks onto WS1 signal (150W) 2012/03/09 NO_OP cmds sent to spacecraft with ITOS, some PTP issues 2012/03/12 WS1 tracks during a maneuver with s/c antenna angle 8.5deg 2012/05/17 successful range data sent to FDF 2012/05/24 PTP updates fix previous command problems 2012/05/27 MMOC data forwarding to ASC & NOAA updated for WS1 2012/06/04 MMOC clock calibration updated for WS1 2012/08/13 WS1 schedule starts being sent to MMOC 2012/09/09 MMOC procedures updated for WS1 2012/09/10 SSMO review of WS1 status and certification plan 2012/09/24 WS1 fixed ground receipt time issue 2012/09/27 MMOC fixed issues reading millisecond field 2012/10/12 VC2 disconnect network problem fixed 2012/10/31 MMOC connects to station status server 2012/11/02 Firewall issues discovered and fixed 2012/11/20 NOAA processing of SIS data from WS1 fixed by delaying data 2012/11/20 1st successful WS1 certification test, IDR files sent to ASC 2012/11/27 2nd successful WS1 certification test, IDR files sent to ASC 2012/11/30 3rd successful WS1 certification test, IDR files sent to ASC 2012/11/30 ACE Mission Director certifies WS1 for ACE operations