ACE Weekly 01/21/2009 - 01/27/2009

All ACE spacecraft subsystems are performing nominally.

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Orbit/Attitude:

	Type        Attitude
	Date        01/21/2009
	DOY         021 2009
	Thrusters   2R 4R+ 4R-
	Duration    13:56 min
	Start       17:59:31z
	Stop        18:13:27z
	HGAStart    -6.88deg
	HGAStop      7.49deg
	SunStart     5.70deg
	SunStop     16.54deg
	SpinStart  5.0016rpm
	SpinStop   5.0052rpm
	Nutation     0.08deg
	Firing      70 pulses
	FuelUsed      0.2283lbs
	FuelRemain  145.0476lbs
	FinalSCMass 1379.308lbs

The next attitude maneuver is scheduled for Monday 02/02/2009.

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OCRs:

None

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Activities:

DOY 026 01/26/2009 - DSS-24 Return To Service Demo
DSS-24 is returning to service after Ka-Band Phase 2 upgrade
(11/03/2008-02/01/2009).  The station had trouble acquiring the low-rate
data during the last 10 minutes of the support.  The station eventually did
acquire low-rate data after the end of track.  The station will investigate
the glitch.  In spite of the glitch, the Demo was deemed successful.  DSS-34
had already undergone a Ka-Band Phase 2 upgrade (the ACE Return To Service
Demo was 09/24/2008).


Data Capture:  100%  DOY 021-027 2009

The risk of data loss has returned to normal.  The viewperiod from northern
hemisphere antennas has been increasing since mid-December and is now 9
hours each day.  Five of the 7 DSN antennas that ACE uses are in the
northern hemisphere.  Also, the overlap between Mars missions has decreased.
Mars has moved ~1 hour ahead of the sun and the current position of ACE
gives ~4 hours of viewperiod that is outside of the Mars viewperiod.

There was no data loss from October 2008 through January 2009.  Although
there were several passes delayed by ~30 minutes due to problems, there were
no passes that were completely lost.  This along with a heightened awareness
of the limited DSN resources during station daylight hours, resulted in no
data loss.


A test of the Multi-Mission Ops Center will be performed Thursday 01/29/2009
1545-1745z.  The ACE and WIND spacecrafts will be commanded with the new
mission software currently under development (ITOS).

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Anomalies:

DOY 020  01/20/2009  S-ACE-0410  G09-0007  DSN Tracking Data To FDF
FDF did not receive tracking data from 01/16/2009 through 01/21/2009.  This
is the same problem as anomaly# G08-0122 that occurred last November
(11/19/2008-11/30/2008).  DSN was notified of the problem on 01/20/2009.
JPL had switched tracking data stots that were incorrectly configured.
IMPACT:  JPL will retransmit the lost tracking data to FDF if necessary.
FDF was still able to perform ACE orbit determination (OD) on 01/20/2009.
The problem was resolved before the next scheduled ACE OD on 01/30/2009.  

DOY 021  01/21/2009  S-ACE-0411  G09-0008  DSS-27 Antenna Stop
The ground antenna stopped in the middle of a support (1607-1626z).  The
ground station performed a remote reset.  DR#G109188
IMPACT:  20 minute telemetry outage was redumped at the end of the support.

DOY 022  01/22/2009  S-ACE-0412  G09-0009  DSS-46 CMD/SLE Problems
DSS-46 was unable to process SLE commands at Beginning Of Track (BOT).  The
problem was resolved when the station unloaded and reloaded the desktop.
DR#C106790
IMPACT:  Activities delayed 15 minutes.

DOY 026  01/26/2009  S-ACE-0413  S09-0001  S3DPU_I limit violation
S3DPU current (S3DPU_I) briefly violated the red high limit (RH > 145mA).
The S3DPU Idle Counter (SSDIDLECTR) was at 72.
	2009-026-18:54:48 - 18:54:50   149.744-150.528mA 
IMPACT:  The last brief S3DPU_I violation was 2008-345:23:33:35.  S3DPU_I is
higher when the instruments are processing more data as indicated by a low
SSDIDLECTR.