ACE Weekly 04/17/2012 - 04/23/2012

All ACE spacecraft subsystems are performing as expected.

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Orbit/Attitude:

	Type        Attitude
	Date        04/23/2012
	DOY         114 2012
	Thrusters   2R 4R+ 4R-
	Duration    17:08 min
	Start       18:39:46z
	Stop        18:56:54z
	HGAStart    -7.58deg
	HGAStop     +7.71deg
	SunStart    12.30deg
	SunStop      5.34deg
	SpinStart   5.0460rpm
	SpinStop    5.0509rpm
	Nutation     0.16deg
	Firing      87 pulses
	FuelUsed      0.2632lbs
	FuelRemain  122.4216lbs
	FinalSCMass 1356.682lbs

The next attitude maneuver is scheduled for Friday 05/04/2012.

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OCRs:

None

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Activities:

Data Capture:  100%  DOY 099-106 2012

The next Solar Exclusion Zone transit (SEZ) is coming up with a minimum
Sun-Earth-Vehicle angle (SEV) of 0.67 degrees on Sunday 5/6/2012.  This
angle is larger than the Nov 2011 transit (0.42 deg) and the Feb 2012
sun crossing (0.16 deg).  The radio solar flux had been extremely low
(<115 sfu) for the past month.  But since April 15, the solar flux has
jumped up to 150 sfu (4/22/2012).  Estimates are that if the solar flux
jumps above ~200 sfu, then there will be data loss (<24 hours) during
the May transit.

WS1 ranging test on Wednesday 04/18/2012.  WS1 continues adjusting the
range equipment configuration to work for ACE.

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Anomalies:

Update on AR#S12-0001  S-ACE-0639  SWEPAM-E Overcount Alarm
The SWEPAM-Electron Overcount Alarm continues to flag since DOY 102
20:32:24z, with 2 brief instances where it returned to zero (DOY 107
1429-1434 & DOY 114 1945-1949).  From the instrument team: "It seems to
be related to a combination of higher counts as we approach solar
maximum, and the fact that around the same time we lowered the count
level we also changed to spending more time operating in a mode in which
alarm flags are not cleared."  The instrument team will look at the data
to determine the next course of action.  IMPACT:  The instrument
automatically reduces voltages when the overcount alarm occurs.