ACE Weekly 09/02/2009 - 09/08/2009
All ACE spacecraft subsystems are performing nominally.
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Orbit/Attitude:
Type Attitude
Date 09/04/2009
DOY 247 2009
Thrusters 2R 4R+ 4R-
Duration 14:47 min
Start 15:01:26z
Stop 15:16:13z
HGAStart -6.98deg
HGAStop 7.51deg
SunStart 5.68deg
SunStop 11.71deg
SpinStart 5.0312rpm
SpinStop 5.0352rpm
Nutation 0.20deg
Firing 75 pulses
FuelUsed 0.2387lbs
FuelRemain 140.9796lbs
FinalSCMass 1375.240lbs
The next attitude maneuver and Station-Keeping #52 are scheduled for
Thursday 09/24/2009
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OCRs:
None
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Activities:
Data Capture: 99.99% DOY 242-249 2009
31 second gap during SSR failover (DOY 244 2009 14:08:16-14:08:47)
The LCROSS mission is no longer declaring spacecraft emergency, but has
increased their DSN usage. DSS-24 and DSS-54 continue to be
unavailable. For most of the passes in the upcoming week, SSR playback
will not be finished until the following pass. If there are no problems
with the passes, all data will be captured.
A DSS-54 Return To Service test will be performed on Wednesday
09/09/2009.
A Multi-Mission Operations Center (MMOC) test will be performed on
Thursday 09/10/2009 (DOY 254 0020-0100z). The spacecraft will be
commanded to hi-rate and data from the previous pass will be redumped.
All data will have been captured by the legacy system.
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Anomalies:
DOY 245 09/02/2009 S-ACE-0458 G09-0051 TPOCC Procedure Problems
The SSR redump procedure (s_ops_plbk_complete) did not start and the
final state of health check procedure did not complete (g_end_day). For
g_end_day, the BinDump command was sent and the spacecraft switched to
BinDump format. TPOCC, however, remained at the line in WAIT UNTIL
(P@DNLK_FORMAT_ID = "BIN_DUMP"). For s_ops_plbk_complete, the
automation software checks TPOCC for the SSR status. When the SSR
playback completed, the automation software did not see the change in
SSR status in TPOCC.
Impact: The pass completed without further commanding. No redumps were
needed and the spacecraft downlink format returned to RTSW at the end of
the pass. Typically, TPOCC has problems when a hardware failure is
imminent or when a process is using excessive cpu/memory. There have
been no problems with subsequent passes.
DOY 248 09/05/2009 S-ACE-0459 S09-0005 Increase in SBE_CT_B
SSR B Single Bit Error Count (SBE_CT_B) increased from 5067 to 5646
since last checked on DOY 238 (08/26/2009). 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)
07/31/2009 4697
08/02/2009 5067 (slice 253)
09/05/2009 5646