ACE Weekly 06/21/2011 - 06/27/2011

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 maneuver are scheduled for Thursday 06/30/2011.

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OCRs:

None


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Activities:

Data Capture:  100%  DOY 149-156 2011

The GRAIL mission is expected to launch 09/08/2011.  ACE has reduced DSN
antenna time during September.  The current published DSN schedule
(through 09/18/2011) has ACE losing ~10% data.  The remainder of the
September DSN schedule is being negotiated.

The SOHO mission is experiencing uplink problems with DSN DSS-27.  On
Tuesday 06/21/2011, the ACE pass with DSS-24 was shortened from 3.5
hours to 1.5 hours so that SOHO could use DSS-24 after having problems
with DSS-27.  The ACE playback was caught up over the next 2 passes.  No
data loss occurred.  Manual intervention was required to shorten the
Tuesday pass since the pass had already started.

The DSS-27 ground antenna will be down for the next 4 weeks starting
Monday 6/27/2011.  DSS-27 is having an Antenna Controller Replacement
(ACR), a 250-Watt S-Band Uplink Install and Cable Wrap Protection.  ACE
uses DSS-27 for most of the passes since ACE's RF Link Margin does not
have problems with DSS-27.  Fortunately, ACE has not had problems
acquiring time with on the other DSN antennas during these 4 weeks.
This is mostly due to longer summertime viewperiods for ACE and other
missions viewperiods having little overlap with ACE.

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Anomalies:

DOY 173  06/22/2011  S-ACE-0617  G11-0044  JPL SLE TLM Provider Problem
The JPL SLE TLM Provider stopped sending telemetry 1 hour after the pass
had started.  JPL requested that ACE disconnect and reconnect the SLE
TLM connections, but at that moment the MMOC SLE software (MUS) crashed.
The MUS software was restarted within 10 minutes and several connections
to MUS were re-established.  DR#N107434
IMPACT:  Manual intervention required.