ACE Weekly 05/18/2007 - 05/24/2007

All ACE spacecraft subsystems are performing nominally.

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Orbit/Attitude:

No maneuvers were completed this week.  The next attitude maneuver is
scheduled for Friday, 05/25/2007.

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OCRs:

DOY 142 (05/22/2007)  GND-179  ROBOTT v1.0.3 Install String 2
This release of the ROBOTT ground automation software provides patches for
transferring files on the Restricted IONet.

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Activities:

RIONET - Testing on String 2 with the new ROBOTT installation continues.  An
operational test will be scheduled next week.

Space Link Extension (SLE) - ACE SLE version 2.1 was delivered to the
Library on April 28, 2006.  Installation in the ACE MOC will not occur until
after the MOC is converted to the RIONET.

A telecon has been scheduled for Thursday 05/31/2007 to discuss the issues
with DSN's SPS viewperiod generation and FDF ephemeris files.

Planning continues for integrating ACE operations into a multi-mission ops
center (MMOC).

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Anomalies:

DOY 138  05/18/2007  S-ACE-0181  G07-0039  TPOCC Crash
The TPOCC ground software displays and TSTOL connection terminated on the
front end workstation.  Other front end processes were not impacted,
including telemetry and commanding processes.  ROBOTT/C&C saw that there was
a terminated TSTOL connection and rebooted itself to ensure that it had a
good connection.  This is possibly an indicator that a hardware failure may
occur.  A similar problem occurred 09/05/2003 (AR#G03-0082) and 11/28/2003
(AR#G03-0119).  On 12/25/2003 (AR#G03-0127), the root drive on the front end
finally failed.
IMPACT:  Minimal since other front end processes (TLM/CMD) were not
impacted.  If the front end does fail completely, a manual failover to the
backup string will be necessary since the other half of the MOC is on the
Restricted IONet.  This would have a larger impact if it occurred while the
MOC was not staffed.

DOY 138  05/18/2007  S-ACE-0182  G07-0040  S3DPU_I Red High
S3DPU current (S3DPU_I) briefly violated the red high limit (RH > 145mA).
	2007-138-11:52:57 - 11:52:59  149.744-154.448mA
IMPACT:  (from Mark Popecki) The increase in the current matches well with
an increase in solar wind density in the middle of the 18th. This suggests
that the current increase is related to event processing. The stability of
the mean is reassuring that there is no upward drift in the current.

DOY 139  05/19/2007  S-ACE-0183  G07-0041  DSS-46 Range Pass Lost
DSS-46 was Red due to several problems and was unable to support the ACE
range support.  Due to a hydraulics replacement on DSS-46 and other DSN
maintenance activities, ACE did not have any southern hemisphere ranging
since DOY 133 (Sunday 05/13/2007).  Because of this, additional DSS-46 time
was acquired later on DOY 140.  DR#C105721
IMPACT:  There should still be sufficient southern hemisphere ranging
between the attitude maneuvers on DOY 130 (Thursday 05/10/2007) and DOY 145
(Friday 05/25/2007).

DOY 139  05/19/2007  S-ACE-0183  G07-0041  DSS-66 AutoTrack Problems
Heavy rains at DSS-66 caused problems with the station's AutoTrack.  The
station switched over to ProgramTrack mode.  DR#M104261
IMPACT:  Minimal.  Playback and commanding had already been completed when
the brief pause in tracking had occurred.

DOY 144  05/24/2007  S-ACE-0184  G07-0042  DSS-66 No TLM at BOT
DSS-66 was unable to maintain lock on the low-rate telemetry at BOT (1400z).
DSS-66 resolved the problem and acquired lock at 1412z.  DR#M104277
IMPACT:  Activities delayed 12 minutes.