ACE Weekly 05/07/2008 - 05/13/2008

All ACE spacecraft subsystems are performing nominally.

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Orbit/Attitude:

No maneuvers were completed this week.  The next attitude maneuver and
Station-Keeping #48 are scheduled for Tuesday 05/20/2008.

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OCRs:

None

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Activities:

The discussion and investigation continues as to why telemetry was not
received at GSFC for the DSN passes on 5/3/2008-5/5/2008 (DOY 124-126) and
other network problems.

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Anomalies:

DOY 128  05/07/2008  S-ACE-0317  G08-0056  ROBOTT/C&C Failed
The MOC automation software (C&C) failed to execute the initial commanding
procedure (g_initial_contact).  Since SSR playback was behind schedule and
DSN time was limited, it was decided to execute the pass manually.  This
problem last occurred on 01/08/2008 (AR#G08-0003)
IMPACT:  The DOY 128 pass was taken manually.

DOY 131  05/10/2008  S-ACE-0318  S08-0002  Increase in SBE_CT_B
SSR B Single Bit Error Count (SBE_CT_B) increased from 3999 to 4533 since
last checked on DOY 123 (05/02/2008).  SBE_CT is tracked as a measure of SSR
health.  This is the first time the SSR has provided the address where the
Single Bit Error occurred (slice 253)
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
                      05/10/2008   4533  (slice 253)
                      

DOY 134  05/13/2008  S-ACE-0319  G08-0056  Telemetry Not Received at GSFC
A network problem caused only a few frames of telemetry data to reach the
ACE MOC from DSS-27.  JPL Comm and Goddard Comm Control were unable to
resolve the problem.  The MOC automation software (ROBOTT) is designed to
command only when telemetry is online in order to perform state-of-health
checks.  Low-rate data recorded at DSN CDR.  DR#N104858
IMPACT:  SSR playback not started.  SSR Failover will occur on DOY 135 at
1115z.