ACE Weekly 01/04/2013 - 01/08/2013

All ACE spacecraft subsystems are performing as expected.  This report
covers 5 days.  Weekly maneuvers & reports had shifted to Thursdays over
the holidays and are now back on Tuesdays.

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Orbit/Attitude:

	Type        Attitude
	Date        01/08/2013
	DOY         008 2013
	Thrusters   2R 4R+ 4R-
	Duration    5:06 min
	Start       18:53:12z
	Stop        18:58:18z
	HGAStart    -8.90deg
	HGAStop     +8.99deg
	SunStart    14.07deg
	SunStop     15.45deg
	SpinStart   5.0794rpm
	SpinStop    5.0805rpm
	Nutation     0.18deg
	Firing      26 pulses
	FuelUsed      0.0876lbs
	FuelRemain  117.0592lbs
	FinalSCMass 1351.319lbs

The next attitude maneuver and station-keeping #64 are scheduled for
Tuesday 01/15/2013.

We have had one southern hemisphere ranging pass between the previous
maneuver (1/3/2013) and this maneuver (1/8/2013).  However, there will
be no more southern hemisphere ranging before the station keeping
maneuver next week.  Southern Hemisphere ranging will be more available
(2 per week) after the station keeping maneuver.

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OCRs:

None

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Activities:

Data Capture:  100%  DOY 365-006 2013


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Anomalies:

None

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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
12/04-12/11   16.0deg    10.9deg    5.1deg
12/11-12/18   16.8deg    11.3deg    5.5deg
12/18-12/27   16.5deg    10.7deg    5.8deg
12/27-01/03   16.0deg     9.1deg    6.9deg
01/03-01/08   15.2deg     7.2deg    8.0deg


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 average 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.