ACE Weekly 07/29/2009 - 08/04/2009
All ACE spacecraft subsystems are performing nominally.
========================================================================
Orbit/Attitude:
Type Attitude
Date 08/03/2009
DOY 215 2009
Thrusters 2R 4R+ 4R-
Duration 14:39 min
Start 15:39:46z
Stop 15:54:25z
HGAStart -7.39deg
HGAStop +7.94deg
SunStart 7.05deg
SunStop 17.55deg
SpinStart 5.0255rpm
SpinStop 5.0297rpm
Nutation 0.09deg
Firing 74 pulses
FuelUsed 0.2360lbs
FuelRemain 141.4192lbs
FinalSCMass 1375.679lbs
The next attitude maneuver is scheduled for Monday 08/17/2009.
=======================================================================
OCRs:
None
========================================================================
Activities:
Data Capture: 99.99% DOY 207-214 2009
31 second gap during SSR failover (DOY 212 2009 09:25:02-09:25:32)
========================================================================
Anomalies:
DOY 211 07/30/2009 S-ACE-0453 G09-0048 Unable to Command--Network
The ACE MOC SLE software was unable to bind to DSS-65. DSS-65, JPL Comm
and Goddard Comm Control were unable to resolve the problem. No
commanding (including SSR playback) was performed. DSS-65 was scheduled
for further testing later in the day. After 9 hours of troubleshooting
over a 15 hour period, a JPL router problem was discovered. A temporary
fix has been implemented until the full problem can be understood.
IMPACT: SSR failover occurred (09:25:02z) before the next pass on DOY
212 (BOT=14:25z). A short 31 second gap occurred during the SSR
failover.
DOY 212 07/31/2009 S-ACE-0454 S09-0003 Increase in SBE_CT_B
SSR B Single Bit Error Count (SBE_CT_B) increased from 4533 to 4697
since last checked on DOY 210 (07/29/2009). 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.
DOY 214 08/02/2009 S-ACE-0455 S09-0004 Increase in SBE_CT_B
SSR B Single Bit Error Count (SBE_CT_B) increased from 4697 to 5067
since last checked on DOY 212 (07/31/2009). SBE_CT is tracked as a
measure of SSR health. The SSR also saved the address in the Soft SBE
Queue; only the second time the SSR has done this. The address
corresponds to slice 253 (out of 0-1023).
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)
07/31/2009 4697
08/02/2009 5067 (slice 253)
The SBE count had been approximately doubling each year. But in the
past 2-3 years, the rate has slowed to approximately a 20% increase each
year.