ACE Weekly 09/20/2011 - 09/26/2011

SWICS is in the same state as of last week (9/19/2011) and collecting
partial science data.  All ACE spacecraft subsystems are performing as
expected.

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Orbit/Attitude:

	Type        Attitude
	Date        09/21/2011
	DOY         264 2011
	Thrusters   2R 4R+ 4R-
	Duration    15:38 min
	Start       13:45:14z
	Stop        14:00:52z
	HGAStart    -7.79deg
	HGAStop     +7.61deg
	SunStart    17.81deg
	SunStop      5.64deg
	SpinStart   5.0146rpm
	SpinStop    5.0186rpm
	Nutation     0.20deg
	Firing      79 pulses
	FuelUsed      0.2492lbs
	FuelRemain  126.7820lbs
	FinalSCMass 1361.042lbs

The next attitude maneuver is scheduled for Friday 10/07/2011.

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OCRs:

No SWICS commanding performed this week.  SWICS remains in ESA-energy
only mode with the MCP voltages off.  This bypasses the TOF system and
collects partial science data.  (MCP=MicroChannel Plate,
ESA=ElectroStatic Analyzer, TOF=Time-Of-Flight).

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Activities:

Data Capture:  99.88%  DOY 261-268 2011
264-06:14:54 - 264-06:15:48         55 sec  DSN DCD problems
265-03:13:32 - 265-03:14:15         44 sec  gap in redump
265-05:16:51 - 265-15:18:44   1 min 54 sec  gap in redump
265-15:25:05 - 265-15:33:10   8 min  5 sec  antenna problem - RT

ACE is doing much better in data capture than originally expected.  Not
recording during passes saves ~15 minutes of antenna time each day (1.75
hours/week).  We also scoured the DSN schedule after GRAIL launched and
found 7 slivers of available antenna time, 35-55 minutes in duration.
This provided 5.7 hours of antenna time over the first 3 weeks of GRAIL.
ACE needs ~19 hours of antenna time per week.  We're still behind in the
SSR playback, but hope to catch up in October when GRAIL is not using so
much antenna time.

Mars Reconnaissance Orbiter (MRO) looked at the possibility of taking
ACE's Friday pass (09/23/2011) to recover from safe-mode.  We told MRO
that we would not release the antenna time and that they would need to
declare a spacecraft emergency to take it.  Eventually, DSN Maintenance
released their antenna time which allowed SOHO to move and give time to
MRO.

FDF Product Server Update
FDF resolved 2 problems this week.  1) The ACE folder had been missing
from the RIONet server (stewart) and is now there.  2) The folders were
not visible on the bonham server are now visible with some (but not all)
accounts.

The Wallops Command and Data Acquisition (WCDA) ground station uses FDF
INP files to provide ACE data to the NOAA Space Weather Prediction
Center (SWPC).  On Friday 09/23/2011, WCDA's account on the current FDF
Product Server was terminated and WCDA was not able to track ACE.  The
FDF analyst emailed the INP files and WCDA tracking was restored that
same day.  INP files are generated every Monday.  We are waiting to hear
if WCDA has a working account on the new system.

During Monday's solar activity, the ULEIS shutter autonomously closed to
6% between 0934z and 1341z.  Exact times for shutter movement will be
provided in next week's report when the recorded data has been
downlinked.

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Anomalies:

DOY 264  09/21/2011  S-ACE-0627  G11-0053  DSN DCD Problems
DSN's Data Capture and Delivery (DCD) system had a double storage
failure.  No telemetry was sent to the MMOC for the remainder of the ACE
pass.  The DCD system did save the data and was available after the
pass.  DR#N107619
Impact:  There is a 55 second gap due to the playback not being cleanly
terminated at the end of the pass (aka SSR stuck in playback).

DOY 264  09/21/2011  S-ACE-0627  G11-0053  DSS-27 Antenna Tracking
20 minutes before End-Of-Track (EOT), the ground station had an "Antenna
Drive Cabinet Comm Lost" alarm.  Telemetry was restored in 8 minutes.
Commanding to the spacecraft was not re-established.  DR#G111980
Impact:  Since the SSR was not in record, the 8 minutes of data loss is
not recoverable.