ACE Weekly 05/10/2011 - 05/16/2011

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 Tuesday 05/17/2011.

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OCRs:

None


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Activities:

Data Capture:  100%  DOY 128-135 2011

This week, ACE will get to 1.41 degrees from the center of the sun (as
seen from Earth) and will get closer in the upcoming transits.  DSN is
not expected to have any problems receiving high-rate data (87648bps)
when the Sun-Earth-Vehicle (SEV) angle is greater than 0.5 degrees.  The
SSR recorders are large enough (2x43 hours) to record all science data
while the SEV angle is less than 0.5 degrees.

	05/19/2011	1.41 degrees
	08/17/2011	0.78 degrees
	11/14/2011	0.41 degrees
	02/08/2012	0.18 degrees
	05/06/2012	0.71 degrees
	08/05/2012	1.23 degrees

However, DLR (Germany) is having difficulties receiving the ACE low-rate
signal (496bps) with their 4m antenna for NOAA Space Weather.  During
the last sun crossing (June 2004), RAL (England) and WCDA (Wallops) were
able track ACE low-rate, even when it was in front of the sun.  NICT
(Japan) was able to track as ACE was close to the edge of the sun.  But
RAL, Wallops and NICT use ~12m antenna.  The DLR antenna replaced the
RAL antenna for NOAA Space Weather services on Oct 1, 2009.

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Anomalies:

DOY 131  05/11/2011  S-ACE-0609  G11-0036  Data Forwarding Problem
ACE and WIND data forwarding both disconnected and automatically
reconnected at 1658z.  NOAA SWPC (ACE) and PWG (WIND) reported no data
after 1640z.  ACE data forwarding was stopped and restarted at 1705z.
NOAA SWPC started receiving ACE data for 16:55z; indicating that data
from DSN was delayed ~10 minutes.  DSN did not report any alarms in
their DCD (Data Capture and Delivery).  The ace_data_fwd and
wind_data_fwd tools did not report any errors and netstat showed
ESTABLISHED connections.
IMPACT:  Minimal.  No data to NOAA Space Weather for 15 minutes.