ACE Weekly 10/31/2012 - 11/06/2012

All ACE spacecraft subsystems are performing as expected.  

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Orbit/Attitude:

	Type        Attitude
	Date        11/06/2012
	DOY         311 2012
	Thrusters   2R 4R+ 4R-
	Duration    11:41 min
	Start       20:45:17z
	Stop        20:56:58z
	HGAStart    -7.50deg
	HGAStop     +8.78deg
	SunStart     6.77deg
	SunStop     10.75deg
	SpinStart   5.0780rpm
	SpinStop    5.0809rpm
	Nutation     0.14deg
	Firing      60 pulses
	FuelUsed      0.1868lbs
	FuelRemain  118.5548lbs
	FinalSCMass 1352.815lbs

The next attitude maneuver is scheduled for Tuesday 11/13/2012.

Please refer to the new section at the end for the sun angles since
starting weekly attitude maneuvers in reference to the SWEPAM
instrument.

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OCRs:

None

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Activities:

Data Capture:  100%  DOY 302-309 2012

A third WS1 certification test was attempted on Friday 11/2/2012.  This
test was to be performed on the current operational system; previous
tests were done with the current backup system.  However, the WS1
firewalls hadn't been updated to allow a connection to the operational
MMOC computer.  The WS1 firewall will be updated in 2 weeks.  This
restarts the count for 3 consecutive successful certification tests.
The next certification test is scheduled for 11/20/2012, which coincides
with a day we are unable to get a DSN pass.

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Anomalies:

DOY 308  11/03/2012  S-ACE-0654  G12-0015  MMOC in test mode
The ACE context on the operational system was configured for a WS1 test
on Friday 11/02/2012.  The ACE context was not reconfigured back for
operations. The Saturday 11/03/2012 pass started with "add_prompts"
enabled and a redump of data scheduled.
IMPACT:  Manual intervention required on Saturday, activities were
delayed 20 minutes while "add_prompts" was disabled and the redump of
old data was terminated.  There was no data loss.

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Average Sun Angles With Weekly Attitude Maneuvers

The following table will be updated each week to provide a history of
the spacecraft sun angle.  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.

Dates        Avg SEV  Avg Sun  Comments
-----------  -------  -------  --------------------------------------
10/18-10/23  5.1deg   11.0deg
10/23-10/28  3.3deg    9.3deg
10/28-11/06  2.0deg    7.3deg  sun-sev=5.3 due to 9days between mnvrs

Notes:
* SEV = Sun-Earth-Vehicle angle.
* When the spacecraft antenna is pointed directly towards earth, the
  spacecraft's sun angle will be equal to the Sun-Earth-Vehicle angle.
* The SEV angle is determined by the size of the orbit around L1.
* With the spacecraft antenna performance and weekly maneuvers, the
  sun angle will be ~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.