ACE Weekly 11/28/2012 - 12/04/2012

All ACE spacecraft subsystems are performing as expected.  

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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.

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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.


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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)

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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.



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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.


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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