ACE Weekly 04/11/03 - 04/17/03

All ACE spacecraft subsystems are performing nominally. An dog-leg attitude 
maneuver was performed successfully on 04/14/03. The next attitude maneuver 
is scheduled for 04/25/03.

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Orbit Events:

The next expected SEV transit is to occur:

Entry: 06/01/03 at 1442Z
Minimum angle: 2.18 degrees on 06/13/03 at 1618Z
Exit: 06/25/03 at 1652Z

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OCRs Executed:

NONE

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Ongoing Activities:

TAPS:
Trending, Analysis and Plotting System (TAPS) development continues with 
emphasis being placed on fixing the DRs attributed to the current release. 
Testing is progressing on both TAPS#1 and TAPS#2.

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Automation (ROBOTT):
Offline and HSM are scheduled to be moved to String 2 on April 15th. 
Command and Control is still being tested by the Automation team. Date for 
release to FOT for testing is still TBD.

Testing will soon begin with the receiving 0158 Monitor data into the 
GENSAA Data Server (GDS).  Assuming all stations send the 0158 monitor data 
to the MOC, testing should be complete by next week.

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Anomalies:

DOY 03102 (04/12/2003) - ACE Anomaly Report #G03-0027 DSN 34m (DSS-27) 
Delayed Commanding
Station 27 had troubles getting and maintaining lock on the spacecraft at 
the beginning of track.  Numerous resweeps of the spacecraft had to be 
performed.  Data was not online until 14:55 (14:50 pass start) and 
commanding was delayed until 15:48 (58 minutes after pass 
start).    IMPACT:  Delayed pass activities.  All lost data was recovered 
on next day's pass.  Additional commands needed to be sent to configure 
spacecraft back into the high data rate.  The inability to command 
inhibited the FOT from disabling an onboard timetag bin which executed and 
put the spacecraft back into the low data rate.  DR# G102630

DOY 03104 (04/14/2003) - ACE Anomaly Report #G03-0028 DSN 34m (DSS-27) SFG 
Problems
Prior to pass start the SFG1 connection was lost. Station operator was 
unable to log into SFG1 to start application. Reboot from machine itself 
still did not connect.  Swapped to SFG2. Still not a complete interface. 
Station operator discovered CISCO switch port for SFGs was in DISABLE 
state. RE-enabled the port and switched back to SFG1. Data resumed and 
commanding enabled.  IMPACT:  Unable to command for 130 minutes delaying 
planned spacecraft maneuver.  Pass had to be extended in order to execute 
spacecraft maneuvers.  All data was recovered.  DR# N100953

DOY 03105 (04/15/2003) - ACE Anomaly Report #G03-0029 DSN 34m (DSS-27) 
Unstable VCOs / Wrong U/L Freq
At 15:00, the FOT requested DSS-27 to change their uplink frequency to 
2098.006 (incorrectly using 2097.99 mHz) and resweep for the uplink.  The 
FOT also informed the station of VC2 hits and high VCOs.  At 15:07, DSS-27 
confirmed changing the uplink frequency to 2098.006 and bringing down their 
carrier.  At 15:10, DSS-27 gave  the FOT a go for command.  The FOT 
immediately noticed good VCOs and the VC2 hits stopped.  A DR was requested 
due to the wrong uplink frequency being used by DSS-27.  At 15:24, the FOT 
started receiving VC2 hits again and informed DSS-27.  DSS-27 stated 
everything appeared fine on their end.  JPL was informed and confirmed 
seeing the degraded data.  IMPACT:  Delayed pass activities.  All data was 
recovered.  DR# G102647

DOY 03105 (04/15/2003) - ACE Anomaly Report #G03-0030 DSN 34m (DSS-27) 
Telemetry Outage / SFG Problems
At 17:03, DSN Monitor and telemetry data dropped out.  The FOT called JPL 
Comm several times but didn't get an answer.  The Ops Chief was called and 
informed of the telemetry loss.  The Ops Chief informed the FOT that they 
are seeing several alarms, some stating the SFG is full.  At 17:20, 
telemetry was back online.  IMPACT:  Delayed pass activities.  All data was 
recovered.  DR# N100958

DOY 03105 (04/15/2003) - ACE Anomaly Report #G03-0031 DSN 34m (DSS-27)  Bad 
Ground Receipt Time
Earth Receipt Time off by -0.054 msec for entire pass.  There's an OPD at 
DSN for them to reboot the TCA before each pass . . . but this is the 3rd 
support with bad time-tags within the past month.
076     DSS-27  -0.073          entire pass
091     DSS-27  -0.020          entire pass
105     DSS-27  -0.054          entire pass
IMPACT:  The incorrect time-tags generate incorrect calibrations of the 
spacecraft clock (done daily, using 2 days worth of data).  The scientists 
decided to disregard the incorrect calibration and instead extrapolated the 
calibration from DOY 104.  DR REQUESTED

DOY 03107 (04/17/2003) - ACE Anomaly Report #G03-0032 DSN 34m 
(DSS-54)  Telemetry Dropout
At 16:27:49 telemetry went off line.  Notified DSS-54 that we were no 
longer receiving telemetry.  DSS-54 switched from TCA channel 1 to TCA 
channel 2.   At 16:31:21 telemetry came back on line.  IMPACT:  None.  All 
data was recovered.  DR# M101543

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Glen A. Miller
Honeywell Technology Solutions Inc.

ACE Flight Operations Team
Goddard Space Flight Center
Building 14, Room W10A
Mail Stop 428.2
Greenbelt, MD 20771

Office: 301-286-7071
Pager: 800-425-3174
Fax:    301-286-1729
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~