ACE Weekly 06/05/2012 - 06/11/2012

All ACE spacecraft subsystems are performing as expected.

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Orbit/Attitude:

	Type        Attitude
	Date        06/07/2012
	DOY         159 2012
	Thrusters   2R 4R+ 4R-
	Duration    15:35 min
	Start       17:53:13z
	Stop        18:08:48z
	HGAStart    -7.29deg
	HGAStop     +7.67deg
	SunStart     5.34deg
	SunStop     17.67deg
	SpinStart   5.0506rpm
	SpinStop    5.0547rpm
	Nutation     0.12deg
	Firing      79 pulses
	FuelUsed      0.2409lbs
	FuelRemain  121.1636lbs
	FinalSCMass 1355.423lbs

The next attitude maneuver is scheduled for Friday 06/22/2012.

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OCRs:

None

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Activities:

Data Capture:  100%  DOY 155-162 2012

The ACE software has been updated for the 6/31/2012 23:59:60z leap
second (MOCRs 443 and 444).

Background Information on ACE Clock Calibration
ACE doesn't have an onboard UTC clock; it has a counter that counts a
little faster than once per second.  Each day, the spacecraft counter is
fit to a line with 2 parameters: slope and offset.  The slope and offset
are used to convert the spacecraft counter to "seconds since C&DH
start".

seconds since C&DH start = (slope * SpacecraftCounter) + offset

To calculate the UTC, add the C&DH start time
(epoch=1997-237-15:48:24.6040) and subtract the number of leap seconds
that have occurred since then (leap seconds=4 starting 7/1/2012).

UTC = (slope * SpacecraftCounter) + offset + epoch - leap seconds

Daily slope and offset values, along with additional information are
available on the ACE Science Center website
(http://www.srl.caltech.edu/ACE/ASC/clock.html)

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Anomalies:

Update on AR#S12-0001  S-ACE-0639  SWEPAM-E Overcount Alarm
The SWEPAM team doubled the overcount threshold on DOY 154 0110z.  The
overcount alarm had already started flagging a day earlier (DOY 153
0100z) and even with the increased overcount threshold, the alarm has
flagged continuously since DOY 153 0207z except for DOY 156 2327z and
DOY 159 0706-1807z.  The instrument team is analyzing the data to
determine the next course of action.  IMPACT:  The instrument
automatically reduces voltages when the overcount alarm occurs.