ACE Weekly 01/10/2012 - 01/16/2012

All ACE spacecraft subsystems are performing as expected.

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Orbit/Attitude:

	Type        Attitude
	Date        01/12/2012
	DOY         012 2012
	Thrusters   2R 4R+ 4R-
	Duration    12:27 min
	Start       17:11:24z
	Stop        17:23:51z
	HGAStart    -4.83deg
	HGAStop     +7.86deg
	SunStart     6.49deg
	SunStop     16.44deg
	SpinStart   5.0407rpm
	SpinStop    5.0443rpm
	Nutation     0.18deg
	Firing      63 pulses
	FuelUsed      0.2018lbs
	FuelRemain  124.2648lbs
	FinalSCMass 1358.525lbs

The next attitude maneuver is scheduled for Monday 01/30/2012.

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OCRs:

A proposal (MOCR 387) has been submitted to allow the spacecraft to
violate the 4 degree sun constraint and drift (no nutation) to a sun
angle of 2 degrees during the February 2012 Solar Exclusion Zone (SEZ)
transit.  This allows the spacecraft antenna to be pointing more
directly towards earth and reduce the risk of data loss.

The 4 degree sun constraint reads as follows: "Operation at a sun angle
(angle between spacecraft +Z axis and sun) much less than 4 deg will
cause: loss of sun pulse or cause multiple sun pulses per spin to be
observed (which makes the apparent spin rate appear faster than it
really is). Multiple sun pulses per spin can occur at small spin
axis/S/C-sunline angles because nutation causes the spin axis to rotate
about the system angular momentum vector changing the rate at which the
sun is moving about the geometric Z-axis."

During the November 2011 solar exclusion zone transit, the sun angle
drifted below 4 degrees (11/15/2011 through 11/20/2011) with the minimum
sun angle of 3.1 degrees on 11/17/2011.  There was no impact to the sun
pulse timing.

On DOY 250 1997, 13 days into the mission, an orbit shaping maneuver
dropped the sun angle to 2.3 degrees.  The sun pulse timing was impacted
due to nutation (up to +/-0.5 seconds in the 12 second rotation), but
the sun pulse still occurred at this small sun angle.

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Activities:

Data Capture:  100%  DOY 008-015 2012

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Anomalies:

None