ACE Weekly Report:  09-13-00

All ACE spacecraft subsystems are performing nominally.  An Attitude 
maneuver was successfully executed on 09-08-00.  The next attitude 
maneuver is scheduled for 09-14-00.

On 09-11-00 commands were sent to SEPICA to load baseline data to SEPICA Fan3
Memory Bank0, Block2.  "This sequence is part of a continuing effort to
understand recent problems with deflection ("Y") measurements.  Routine data
processing was directed to the spare memory on 09-12-00, and so far the
results are promising. The next solar active period will fill in measurements
that are not covered by the built-in calibration source."  The instrument team
will then know "if the data processing is completely normal again. If this has
fixed the problem by using a different section of memory, then the original
memory might be damaged."

History - SEPICA Anomaly:

On 07-07-00 the SEPICA Instrument team informed the FOT that they had recently
determined that "since day 2000/107, three measurement channels have not been
coming out of SEPICA. These channels are known as Y10, Y11 and Y12.  The
information they provide is essential for ionic charge state measurement,
which is one of the primary missions of the SEPICA instrument."

Initial observations by the SEPICA Instrument team led them to believe it was
a data processing problem, as opposed to a hardware failure.  Several OCRs
have been executed as part of a continuing investigation and to trouble shoot
the problem.  The latest status report from the instrument team states, "We
are getting good data from one half and good data from part of the other half.
One half is sufficient for science output."

The Instrument team believes that the memory may be damaged and hope to test
this by redirecting data to spare memory.  The FOT is working with the
Instrument team to develop and verify the necessary command load procedures.
This command activity was performed on 09-11-00.