ACE Weekly 08/26/2009 - 09/01/2009

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 09/04/2009.  Station-Keeping #52 is scheduled for
Thursday 09/24/2009

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OCRs:

None

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Activities:

Data Capture:  99.99%  DOY 235-242 2009
31 second gap during SSR failover (DOY 240 2009 06:20:51-06:21:21)
31 second gap during SSR failover (DOY 244 2009 14:08:16-14:08:47)

The LCROSS mission declared a spacecraft emergency on Saturday
08/22/2009 (DOY 234).  ACE has given up passes on DOY 239 and DOY 243
resulting in brief 31-second gaps during the SSR failover.  Further
passes may be lost.  (Note, the DOY 244 gap actually falls in next
week's reporting period.)

Background Information: ACE utilizes 6 DSN antennas (24,27,34,45,54,65).
DSS-54 has been unavailable since July 1 due to the KA-Band Phase 2
upgrade.  DSS-54 is expected to return to service on October 5.  DSS-24
is unavailable for the month of September.
	ACE ground automation gives some flexibility in moving passes
and this has been the major factor in avoiding major data loss in the
past week.  There are 2 minor disadvantages to the ACE ground automation
system that should be mentioned: 1) Problems with commanding will result
in a lost pass (e.g. the JPL router problem on DOY 211) 2) Unable to use
DSN stations with only S-Band downlink.  Over the years DSN problems
have become more infrequent and there is only one DSN station that has
S-Band downlink but no S-Band uplink (DSS-15).  Therefore, on the whole,
ACE ground automation fits well for ACE's needs.

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:

None