ACE Weekly 04/23/2008 - 04/29/2008

All ACE spacecraft subsystems are performing nominally.

============================================================================
Orbit/Attitude:

No maneuvers were completed this week.  The next attitude maneuver is
scheduled for Monday 05/05/2008.  Station-keeping #48 is scheduled for
Tuesday 05/20/2008.

===========================================================================
OCRs:

None

============================================================================
Activities:

None

============================================================================
Anomalies:

DOY 114  04/23/2008  S-ACE-0305  G08-0045  DSS-66 Telemetry Problems
DSS-66 was unable to lock onto telemetry with either Telemetry Control
Processor (TCP) at Beginning Of Track.  TCPs were reloaded and eventually
able to lock onto telemetry.  DR#M104800
IMPACT:  Activities delayed 37 minutes.  SSR playback had already been
behind due to the lost pass on DOY 112.  SSR playback was finally caught up
on DOY 116.


DOY 117  04/26/2008  S-ACE-0306  S08-0001  Increase in SBE_CT_B
SSR B Single Bit Error Count (SBE_CT_B) increased from 3238 to 3999 since
last checked on DOY 111 (04/20/2008).  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
                      01/12/2007   3125
                      06/21/2007   3238
                      04/26/2008   3999


DOY 118  04/27/2008  S-ACE-0307  G08-0046  DSS-24 Transmitter
DSS-24 transmitter tripped off at 1448z and uplink was unavailable until
1537z.  Telemetry outages occurred from 1448-1509z and 1535-1536z.
IMPACT:  Initial commanding had completed at 1444z.  ACE MOC automation
delayed commanding for state-of-health checks until uplink was restored.
Telemetry outages caused automated attitude determination to fail; attitude
determination was manually performed on the next day.


DOY 119  04/28/2008  S-ACE-0308  G08-0047  DSS-24 Transmitter
DSS-24 transmitter interface had problems at Beginning Of Track.  Comm
personnel reseated cables.  DR#G108558
IMPACT:  Activities delayed 24 minutes.