ACE Weekly 03/18/2009 - 03/24/2009

All ACE spacecraft subsystems are performing nominally.

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Orbit/Attitude:

	Type        Attitude       SK-50
	Date        03/23/2009     03/23/2009
	DOY         082 2009       082 2009
	Thrusters   2R 4R+ 4R-     3A 4A
	Duration    16:03 min      49.751 sec
	Start       15:43:11z      17:41:48z
	Stop        15:59:14z      17:42:38z
	HGAStart    -7.30deg	   +7.90deg
	HGAStop     +7.90deg       +7.51deg
	SunStart     8.95deg        8.58deg
	SunStop      8.58deg        8.52deg
	SpinStart   5.0129rpm      5.0177rpm
	SpinStop    5.0177rpm      5.0054rpm
	Nutation     0.27deg        0.13deg
	Firing      81 pulses      Continuous
	FuelUsed      0.2604lbs      0.1777lbs
	FuelRemain  144.1036lbs    143.9259lbs
	FinalSCMass 1378.364lbs    1378.186lbs

The next attitude maneuver is scheduled for Thursday 04/16/2009.

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OCRs:

None

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Activities:

Data Capture:  100%  DOY 074-081 2009

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Anomalies:

DOY 064  03/05/2009  S-ACE-0420  G09-0016  TAPS2 Data Capture Failure
The trending software (TAPS) data capture daemon stopped receiving
telemetry data on DOY 064.  The data capture daemon occasionally fails
when work on the network is being performed.  This last occurred
06/28/2007.
IMPACT:  Minimal.  The data was copied from TAPS1.


DOY 077  03/18/2009  S-ACE-0421  S09-0002  Increase in SBE_CT_A
SSR A Single Bit Error Count (SBE_CT_A) increased from 510 to 525 since
last checked on DOY 123 (03/16/2009).  SBE_CT is tracked as a measure of
SSR health.
IMPACT:  Minimal.  Single Bit Errors are automatically corrected by the
SSR and occur infrequently.  No non-correctable errors (Hard Single Bit
Errors & Double Bit Errors) have occurred throughout the mission.

SBE_CT_A              SBE_CT_B
12/01/1999   15       09/06/2003   286
02/25/2003   30       09/22/2004   608
06/05/2003   270      11/15/2004   858
07/26/2007   510      11/07/2006   2118
03/18/2009   525      01/12/2007   3125
                      06/21/2007   3238
                      04/26/2008   3999
                      05/10/2008   4533  (slice 253)


DOY 079  03/20/2008  S-ACE-0422  G09-0017  No Lock on Receiver B
When DSS-24 established the uplink at BOT, the spacecraft Receiver B did
not lock on the uplink.  This occurs 1-3 times a year.  Since
Transmitter A is transmitting, DSN sweeps the uplink to lock on Receiver
A.  During this sweep, Receiver B usually also locks on the uplink
automatically.  There is no problem with the spacecraft, but the FOT
tracks these occurrences with anomaly reports for trending purposes.
This last occurred on 11/26/2008 (AR#G08-0118)
IMPACT:  Minimal.  C&DH B timers were reset on the next day (DOY 080).