ACE Weekly 08/01/2011 - 08/08/2011

All ACE spacecraft subsystems are performing nominally.

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Orbit/Attitude:

	Type        Attitude       
	Date        08/03/2011
	DOY         215 2011
	Thrusters   2R 4R+ 4R-
	Duration    18:39 min
	Start       19:04:15z
	Stop        19:22:54z
	HGAStart    -8.35deg
	HGAStop     +6.75deg
	SunStart     6.78deg
	SunStop     10.61deg
	SpinStart   5.0053rpm
	SpinStop    5.0103rpm
	Nutation     0.18deg
	Firing      94 pulses
	FuelUsed      0.2926lbs
	FuelRemain  127.3744lbs
	FinalSCMass 1361.635lbs

The next attitude maneuver is scheduled for Wednesday 08/10/2011.

During Solar Exclusion Zone (SEZ) transits, it becomes more difficult to
maintain the >4 degree sun constraint and the <8 degree antenna
constraint.  A proposal to allow ACE to drift through the 4 degree sun
constraint was discussed in order to reduce the number of maneuvers
needed during the SEZ transits.  It was decided to maintain the 4 degree
sun constraint because of minimal benefit in reduced maneuvers and the
risk of possible undocumented reasons for the 4 degree sun constraint.


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OCRs:

None


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Activities:

Data Capture:  100%  DOY 212-219 2011

The GRAIL mission is expected to launch 09/08/2011.  ACE has reduced DSN
antenna time during September.  The current schedule has ACE losing ~15%
data over 3 weeks in September.  The data loss will be greater if there
are problems with any of the passes.


During last week's solar activity, the ULEIS shutter autonomously
closed.  The ULEIS shutter can also close down to 1% if there is enough
solar activity.
	Fri Aug 5 2011, DOY 217 17:19:26z closed to 25%
	Fri Aug 5 2011, DOY 217 18:06:22z closed to 6%
	Sat Aug 6 2011, DOY 218 14:20:14z open   to 25%
	Sun Aug 7 2011, DOY 219 22:33:02z open   to 100%


SOLAR EXCLUSION ZONE (SEZ):  Next week (8/17/2011), ACE will get to 0.78
degrees from the center of the sun (as seen from Earth) and will get
closer in the upcoming transits.  DSN is not expected to have any
problems receiving high-rate data (87648bps) when the Sun-Earth-Vehicle
(SEV) angle is greater than 0.5 degrees.  The SSR recorders are large
enough (2x43 hours) to record all science data while the SEV angle is
less than 0.5 degrees.

	08/17/2011	0.78 degrees
	11/14/2011	0.41 degrees
	02/08/2012	0.18 degrees
	05/06/2012	0.71 degrees
	08/05/2012	1.23 degrees


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Anomalies:

None