ACE Weekly 12/26/2007 - 01/01/2008

All ACE spacecraft subsystems are performing nominally.

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Orbit/Attitude:

	Type        Attitude
	Date        12/28/2007
	DOY         362 2007
	Thrusters   2R 4R+ 4R-
	Duration    13:06 min
	Start       16:22:55z
	Stop        16:36:01z
	HGAStart    -4.98deg
	HGAStop     +7.45deg
	SunStart    10.85deg
	SunStop      6.77deg
	Nutation     0.44deg
	Firing      67 pulses
	FuelUsed      0.2196lbs
	FuelRemain  152.6968lbs
	FinalSCMass 1386.957lbs

The next attitude maneuver is scheduled for Monday, 01/07/2008.
Station-Keeping #46 has been tentatively scheduled for Thursday 01/17/2008.

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OCRs:

None

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Activities:

34m HEF S-Band Transmitter
DSS-45 was tested Monday 12/28/2007.  The ACE MOC successfully binded at
19:41:00 (BOT-19min) but the bind was lost at 19:43:11.  The ACE MOC
software attempted a bind once a minute and was finally successful at
20:01:41.  The reasons remain unknown (DR#C106089).  The GSFC Metric
Tracking Data Evaluation (MTDE) group received good Range and Doppler data.
The uplink signal strength measured by the spacecraft was
	Hi-Gain Antenna   =  -98 dBm
	BroadBeam Antenna = -112 dBm
This signal strength is more than adequate and is comparable to DSS-27
(another 34m antenna with 200W transmitter).


The risk of data loss has increased for the December-January time frame.  If
there are problems with the passes, it may not be possible to
acquire additional DSN time.  Refer to 12/25/2007 weekly for further
explanation.

For 3 supports (Friday 12/14, Friday 12/21 and Wednesday 12/26), DSS-46 has
had significant problems with transmitting commands received via SLE.  DSN
is aware of the problem and provided additional engineers to monitor the
DSS-46 pass on Monday 12/31.  During the Monday 12/31 pass, there were no
problems observed.  DSN is reviewing their log files for any differences in
the configuration for these successful and unsuccessful passes.

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Anomalies:

DOY 360  12/26/2007  S-ACE-0259  G07-0111  DSS-46 SLE - CMDs Not Transmitted
ACE MOC had a successful bind with the station.  However, the station's SLE
indicated commands received but not processed.  Station rebooted the TCP but
only one command would be successful and the bind would be lost.  The
station rebooted the TCP for each command sent until the playback had
started.  DR#C106073
IMPACT:  SSR Playback delayed 2 hours.

DOY 361  12/27/2007  S-ACE-0260  G07-0106  DSS-46 Red Due to Lightening
The station's Antenna Interface Unit (AIU) appeared to have taken a direct
lightning strike and could not be reset prior to the scheduled ACE track.
IMPACT:  Fortunately, additional DSN time was available and the SSR Playback
was completed on DOY 362.