ACE Weekly 10/05/2010 - 10/11/2010

All ACE spacecraft subsystems are performing nominally.

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Orbit/Attitude:

No maneuver was completed this week.  The next attitude maneuver is
scheduled for Friday 10/15/2010.

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OCRs:

None

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Activities:

Data Capture:  96.40%  DOY 276-283 2010
There is a 6 hour 3 minute 5 second gap for DOY 280. 12:31:38 - 18:34:42
See Anomaly Reports: G10-0055, G10-0060 and G10-0061

Two smaller gaps due to ground station (DSN DR#G110650).
Not redumped due to being behind in SSR playback.
342 seconds  2010-282-08:17:04 - 08:22:45
 22 seconds  2010-282-08:22:51 - 08:23:12

There is a higher than normal risk of data loss from October 2010
through February 2011.  If there are problems with the passes, it may
not be possible to acquire additional DSN time.  This is expected during
winter months.  See weekly reports on 01/25/2007, 12/25/2007 and
10/14/2008.  Note, there was not as much competition for DSN antenna
time last year; see weekly report on 12/15/2009.

* Mars is on the opposite side of the sun, which occurs every 2 years.
The viewperiods for the Mars missions (MRO, MEX, M01O, etc) and others
(Messenger, New Horizons, Voyager, etc) overlap with with L1 missions
(SOHO, WIND, ACE) for the next few months.
* In the winter months, viewperiods from antennas in the northern
hemisphere are shorter.  Since 4 of the 6 antennas are in the northern
hemisphere (Madrid, Spain & Goldstone, California), overall antenna time
is reduced.
* DSN continues a maintenance schedule where every antenna is
unavailable during daylight hours one day each week.


NOAA Space Weather Prediction Center does not have a backup antenna.
NOAA SWPC currently has antenna time with NICT (Japan), DLR (Germany),
and Wallops (Virginia).  This week, NICT will be down on 10/09, 10/10
and 10/13 for maintenance.  The network connection to the Air Force
Satellite Control Network (AFSCN) was lost on September 1, 2010 with the
closing of the Onizuka Air Force Base.  There are plans to add a network
through Vandenberg Air Force Base, but that has not been implemented.
Note, the NOAA SWPC operations is separate from the Goddard flight
operations, but this information is worth noting and therefore included
in this weekly report.

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Anomalies:

DOY 280  10/07/2010  S-ACE-0538  G10-0055  DSS-24 Power Outage
The DSN Goldstone complex experienced a 5 minute commercial power outage
before generators came online.  Tracking and uplink resumed after 76
minutes.  DR#G110626
IMPACT:  No realtime data to NOAA Space Weather for 76 minutes.  55
minutes of data dumped on the following pass (55 minutes = 9.1 hours of
playback data).


DOY 281  10/08/2010  S-ACE-0539  G10-0056  ITOS tm_controller
ITOS was unable to process telemetry due to a "timeout reading from
tm_controller".  ITOS was restarted before beginning of track.  (DR
CDSID#00027515)
IMPACT:  Manual intervention required.  No delay in activities.

Update on ITOS tm_controller.  It appears that disconnecting remote
event windows has not eliminated the tm_controller problem.  (See last
week's report)


DOY 281  10/08/2010  S-ACE-0540  G10-0057  MUS CMD process terminated
The MMOC SLE (MUS) cmd process (ace-d24-cmd) terminated unexpectedly 2
minutes after beginning of track.  The MUS CMD process was restarted
within 6 minutes.  This last occurred on 08/28/2010 (AR#G10-0042)
IMPACT:  Manual intervention required.  Activities delayed 6 minutes.


DOY 281  10/08/2010  S-ACE-0541  G10-0058  SLE CMDs Not Transmitted
DSS-24 had successfully transmitted commands at the beginning of the
pass (1720-1836z).  At 2013z, the ground station's SLE FCLTU Production
State was interrupted.  All subsequent commands were rejected by the
station (DR#G110641).  This problem last occurred 10/01/2010
(AR#G10-0052).  MOCR 222 has been submitted for the MMOC to
automatically disconnect and reconnect SLE FCLTU when commands are
rejected by the station.
IMPACT:  SSR not commanded to Idle.  See AR#G10-0059


DOY 281  10/08/2010  S-ACE-0542  S10-0008  SSR B Stuck in Playback
When the SSR playback is longer than the pass, the SSR is commanded to
idle before switching to the low-rate (RTSW) data format.  Problems with
the SLE CMD connection (AR#G10-0058) prevented SSR B from being
commanded to Idle.  When this occurs, the SSR is stuck in Playback.
Impact:  The ground procedures are designed to handle this contingency
by idling the SSR at the beginning of the next support and redumping any
missing data.  This has occurred 5 other times in the past.
	01/12/2005 AR#S05-0002 
	12/01/2005 AR#G05-0148
	11/04/2008 AR#G08-0109
	10/04/2009 AR#S09-0007
	05/11/2010 AR#S10-0002


DOY 282  10/09/2010  S-ACE-0543  G10-0059  ITOS tm_controller
ITOS was unable to process telemetry due to a "timeout reading from
tm_controller".  ITOS was restarted before beginning of track.  (DR
CDSID#00027515)
IMPACT:  Manual intervention required.  No delay in activities.


DOY 282  10/09/2010  S-ACE-0544  G10-0060  DSS-27 Transmitter RED
DSS-27 transmitter was declared RED on DOY 280 due to being unable to
move the antenna in either axis.  (DR#G110646)
IMPACT:  The pass was lost.  See AR#G10-0061


DOY 282  10/09/2010  S-ACE-0545  G10-0061  6 hours data loss
The SSR playback was behind schedule by 55 minutes (=9 hours) due to the
DSS-24 power outage on DOY 280.  Some of that was caught up on the DOY
281 pass, but the SSR playback was still behind by 36 minutes (=6
hours).  With DSS-27 RED on DOY 282, there was limited antenna time
available and a 1-hour pass was scheduled for DSS-45.  In the past,
short passes have been taken manually.  For example, see 9/22/2009
weekly concerning the LCROSS spacecraft emergency and manual pass on DOY
266 2009.  On DOY 282 2010, however, no manual intervention occurred.
IMPACT:  The SSR ground procedures were executed without intervention.
The ground procedures noted the limited time available and did not
redump the 36 minutes of SSR carryover from the DOY 281 pass.


DOY 284  10/11/2010  S-ACE-0546  G10-0062  ITOS tm_controller
ITOS was unable to process telemetry due to a "timeout reading from
tm_controller".  ITOS was restarted before beginning of track.  (DR
CDSID#00027515)
IMPACT:  Manual intervention required.  No delay in activities.