ACE Weekly 05/24/2011 - 05/30/2011

All ACE spacecraft subsystems are performing nominally.

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Orbit/Attitude:

	Type        Attitude
	Date        05/26/2011
	DOY         146 2011
	Thrusters   2R 4R+ 4R-
	Duration    13:16 min
	Start       14:19:54z
	Stop        14:33:10z
	HGAStart    -5.85deg
	HGAStop     +7.44deg
	SunStart     6.28deg
	SunStop     10.49deg
	SpinStart   5.0898rpm
	SpinStop    5.0933rpm
	Nutation     0.10deg
	Firing      68 pulses
	FuelUsed      0.2146lbs
	FuelRemain  128.6844lbs
	FinalSCMass 1362.944lbs

The next attitude maneuver is scheduled for Monday 06/06/2011.

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OCRs:

None


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Activities:

Data Capture:  99.99%  DOY 142-149 2011
2 small 31 second gaps due to DSN power problems and automated on-board
SSR failovers
31 seconds 144-12:40:06 - 12:40:36  AR#G11-0038
31 seconds 148-09:02:44 - 09:03:14  AR#G11-0040

Update on NOAA Space Weather Prediction Center tracking of ACE
NOAA continues to have a gap in their space weather tracking due to the
loss of the antenna at NICT (Japan).  The gap has narrowed to 3 hours as
the spacecraft position and earth tilt improve visibility at WCDA
(Wallops) and DLR (Germany).  The Near Earth Network (NEN) Alaska
Satellite Facility (ASF) and the NOAA's Gilmore Creek Facility continue
to investigate their ability to track ACE.  FDF is expected to provide
INP files for ASF and Gilmore Creek in a few days.

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Anomalies:

DOY 146  05/26/2011  S-ACE-0612  G11-0039  D27 Equipment Problems
Problems with DSS-27's Global Control Engine resulted in loss of ground
antenna control (1506z).  The ground station rebooted their systems and
telemetry returned (1550z).  Uplink was re-established at 1558z.
DR#G111602
IMPACT:  44 minute realtime data outage to NOAA Space Weather.  SSR
redump continued on the following support (30 minutes).

DOY 147  05/27/2011  S-ACE-0613  G11-0040  D27 Power Outage
The DSN ground station was experiencing a power outage at ACE's
Beginning Of Track (1535z).  Power was restored, telemetry was online at
1701z and the uplink established 1733z.  With only 1.5 hours left in the
pass, the DOY 146 redump was performed and the SSRs were not swapped.
DR#G111615
IMPACT:  No impact to NOAA Space Weather since the spacecraft remained
in the low data rate during this time.  SSR failover and 31 second data
gap occurred on DOY 148.

DOY 148  05/28/2011  S-ACE-0523  S10-0007  Increase in SBE_CT_B
SSR B Single Bit Error Count (SBE_CT_B) increased from 7339 to 7918
since last checked on DOY 145 (05/25/2011).  SBE_CT is tracked as a
measure of SSR health.  Note, SSR errors will now be tracked in a single
anomaly report.
IMPACT:  Minimal.  Single Bit Errors are automatically corrected by the
SSR.  No non-correctable errors (Hard Single Bit Errors & Double Bit
Errors) have occurred throughout the mission.

	       SBE_CT_A  SBE_CT_B
	1999   15
	2000
	2001
	2002
	2003   270       286
	2004             858
	2005
	2006             2118
	2007   510       3238
	2008             4533
	2009   525       6839
	2010   780       7339
	2011             7918