ACE Weekly 04/09/2015 - 04/14/2015

ACE spacecraft subsystems are performing as expected.
 
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Orbit/Attitude:

	Type           Attitude
	Date          04/14/2015
	DOY            104 2015
	Thrusters      2R 4R+ 4R-
	Duration      14:25 minutes
	Start          20:06:47z
	Stop           20:21:12z
	ra,decStart    30.25,0.89
	ra,decStop     38.55,11.55
	ra,decExpect   38.96,11.79
	Deviation     0.47deg (-3%)
	HGAStart       -8.17 deg
	HGAStop        +8.51 deg
	SunStart       11.56 deg
	SunStop        15.94 deg
	SpinStart     5.0109 rpm
	SpinStop      5.0152 rpm
	Nutation        0.16 deg
	Firing         73 pulses
	FuelUsed        0.2192 lbm
	FuelRemain     99.0504 lbm
	FinalSCMass   1333.310 lbm

ACE will cross the ecliptic plane 4/29/2015.  This maneuver and the next
maneuver are longer than usual because the spacecraft attitude will
change from pointing below the ecliptic plane to pointing above the
ecliptic plane.

The longer maneuver likely expelled some trapped nitrogen and maneuver
performance is slightly below the recent average (-3% versus better than
-2%).

The next maneuver is scheduled for Tuesday 4/21/2015.

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OCRs:

None
 
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Activities:

Data Capture:  99.990%  DOY 095-102 2015
  DOY 098 08:24:09-08:24:39   31 second gap SSR full & failover
  DOY 101 12:34:15-12:34:42   28 second gap while catching up on data

Data playback had been behind schedule due to lost passes on DOY 097 &
DOY 098 (see previous report).

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Anomalies:

DOY 102 04/12/2015  S-ACE-0523  S10-0007  Increase in SBE_CT_B
SSR B Single Bit Error Count (SBE_CT_B) increased from 14066 to 14206
sometime between 04/05/2014 and 04/12/2015.  SBE_CT is tracked as a
measure of SSR health.
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             10995
	2012             13302
	2013
	2014             14066
	2015             14206