ACE Weekly 09/06/2011 - 09/12/2011

The SWICS instrument trigger anomaly is still being investigated.  All
other ACE spacecraft subsystems are performing as expected.

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Orbit/Attitude:

No maneuvers were completed this week.  The next attitude maneuver is
scheduled for Wednesday 09/21/2011.

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OCRs:

DOY 250 (09/07/2011)  1240-1247z  SWICS MOCR 338
SWICS was powered on after being powered off on DOY 245.  The trigger
problem returned as the instrument temperature increased.  The FSR is
back at the same high value, ~30,000, that had been seen before the
instrument was powered off.  The voltages were not turned back on.
(FSR=Front SEDA Rate, SEDA=Secondary Electron Detector Assembly)

DOY 251 (09/08/2011)  1609-1644z & 1752-1805z  SWICS MOCR 338
SWICS CPT Functional Test was performed.  This put the instrument
through several calibration steps, which use the internal TOF and energy
calibration pulsers and cycled the instrument through the four possible
trigger modes (TOF only; energy only; TOF and energy; and TOF *or*
energy).  The instrument responded correctly in each of these modes.
(CPT=Comprehensive Performance Test, TOF=Time Of Flight)

The internal calibration pulsers seem to interfere with the noise signal
and the FSR dropped to ~512.  It is believed that the pulsers exclude
some of the normal event circuit, portions of which could be causing the
trigger problem.  The instrument team is investigating this in detail.
The pulsers also exclude real events and thus impact science data.

At the end of commanding on DOY 251, the instrument was left in manual
mode with the pulsers off and the trigger mode set to TOF and energy.
The voltages have remained off since DOY 238.  More testing/commanding
will be performed Tuesday 09/13/2011.


DOY 250 (09/07/2011) MOCR 339 SSR Procedure Changes for GRAIL
Three major changes in Solid State Recorder (SSR) procedures were
implemented to reduce data loss during the GRAIL launch and early orbit.
It is expected that these changes should reduce the data loss from
around 15% to about 7%.  Items 1 & 2 are temporary and Item 3 is
permanent.

1) When starting an SSR playback, the other SSR is NOT put into record.
   Instead, the real-time (VC1) data format is switched to science and
   a Time-Tag Bin (#3) is loaded to start recording at 1 minute before
   End Of Track (EOT).
2) The Time-Tag Bin (#3) executes the same Block Bins (#2,#3) that are
   used by the SSR failover Autonomy Bins (#41,#42) when the SSR is
   full.  The Block Bins have been reloaded to re-enable SSR failover
   after recording starts.
3) At the start of a pass, the procedures will attempt to finish the
   playback from the previous pass.  But if the remaining time is short
   (<30 minutes) the other SSR playback will not be started.  The SSR
   will remain recording until it is full and an SSR failover occurs.


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Activities:

Data Capture:  99.99%  DOY 247-254 2011
DOY 250 15:21:40-15:22:17  38 seconds  ADC covers

The 38 second gap occurred when the new SSR procedures were first
implemented.  The ADC data format includes data from 4.5 of the 9
instruments CRIS, EPAM, MAG, SWEPAM-Ion & SIS.  Not included are
SWEPAM-Electron, SWICS, SWIMS, SEPICA & ULEIS.  SEPICA is powered off
and SWICS is having a trigger problem.

GRAIL finally launched on Saturday 09/10/2011.  Data loss due to limited
antenna time is expected to begin Thursday 09/15/2011 (DOY 258).

FDF has provided the IP address for their new product server.  The MMOC
was finally able to establish a connection on Monday 09/12/2011.  User
accounts and other configuration are being worked on.

For NOAA Space Weather Prediction Center, the NICT antenna (Japan) will
be unavailable 9/13 through 9/15.  There is currently a 6 hour gap
between the WCDA antenna (Wallops, Virginia) and the DLR antenna
(Germany).  NOAA SWPC is working with their partners to fill this gap.

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Anomalies:

None