ACE Weekly 08/09/02 - 08/15/02

All ACE spacecraft subsystems are performing nominally. An attitude 
maneuver was executed on 08/13/02. The next attitude maneuver is scheduled 
for 08/23/02.

This is Paul Douglas' last week with ACE.  The FOT would like to thank Paul 
for all his hard work over the years and wish him Good Luck at his new job.

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OCRs Executed:

None

============================================================================
Ongoing Activity:
The engineering test to determine the new HGA constraint is continuing. The 
current constraint is 6.0 deg., with current tests reaching 6.5 degrees.

The FOT has been monitoring the Signal Strength, the MFR AGC levels, and 
the Signal-to-Noise Ratios(SNR). The drop in RF levels from an HGA angle of 
0 deg to 6 deg has been approximately 3dB. There has been no loss of 
telemetry due to the increased HGA angles.  Analysis is ongoing to 
determine new HGA angle constraint.

The following HGA angles and range values are from FDF.
Man Date Pre Man   Post Man    Earth-ACE Range
03/28/02 -4.58 deg  +4.38         1408287 km
04/04/02 -4.35      +4.50         1414808
04/11/01 -5.09      +3.79         1428491
04/18/02 -5.16      +3.85         1440512
04/26/02 -5.77      +5.56         1455949
05/06/02 -5.72      +5.43         1493008
05/17/02 -5.81      +5.31         1527979
05/28/02 -4.34      +4.88         1550263
06/06/02 -2.38      +5.96         1576064
06/20/02 -6.57      -3.66         1590405
06/26/02 -6.43      +5.94         1592458
07/12/02 -6.5       +6.5          1598879
07/30/02 -6.5       +6.5          1567441
08/13/02 -5.34      +6.43         1532343

============================================================================
TPOCC Release 5.2 String 2 Testing Status

Testing on String 2 is still in progress.  No major discrepancies have been 
reported.  Expected completion date is August 23, 2002.

============================================================================
Anomalies:

DOY 02224 (08/12/2002)ACE Anomaly #G02-0092 TPOCC - Lost connection state 
with manager
ac1fe1a lost connection with state manager at 13:19:27.  At the time the 
FOT had been bringing up pages and generating a quick page. Telemetry and 
commanding unaffected.  IMPACT:  ac1fe1a unable to display telemetry pages.

DOY 02224 (08/12/2002)ACE Anomaly #G02-0093   DSN - D27 Problems
Received degraded telemetry throughout pass with D27.  Station reported SUN 
RFI at the TGC.  IMPACT: Not able to complete dumping of recorders.  Next 
day's pass extended to accommodate additional recorder dumps.  DR# G101495

DOY 02224 (08/12/2002)ACE Anomaly #G02-0094   DSN - No Monitor Block Data
At 13:54:44 monitor blocks went offline.  D27 informed us that the Complex 
Supervisor software had died.  The station restored monitor block data at 
14:23.  IMPACT:  Loss of monitor block for ~ 30 minutes.  DR# G101493

DOY 02224 (08/12/2002)ACE Anomaly #G02-0095  DSN - Antenna problems
At 14:06:50 telemetry went offline.  D27 reported the antenna lost pointing 
due to the Complex Supervisor software being down.  IMPACT:  No telemetry 
for 50 minutes.  The data was recovered during the next day's support.  DR# 
G101494

DOY 02227 (08/15/2002)ACE Anomaly #G02-0096  DSN - Incorrect Modulation Index
After the first three commands of the day were sent to the spacecraft, the 
RCVR AGC's dropped significantly.  The station reset the mod index and 
commanding was nominal thereafter.  IMPACT: Yellow Low limit violations on 
RCVR_B_AGC.  All commands sent were verified. DR# G101507

DOY 02227 (08/15/2002)ACE Anomaly #G02-0097  DSN - Tlm Loss/Bad TCA at D27
At 16:06:36 telemetry went offline, while the FOT was sending the LOS TTBin 
Load to the spacecraft.  Telemetry came back online at 16:07:02 and the cmd 
was retransmitted and verified.  At 16:23:48 the FOT started to see VC2 
sequence errors. D27 reacquired the receivers to restore telemetry.  For 
the degraded telemetry D27 swapped the TCA to Ch 2 and performed a hard 
reset of Ch 1.  Telemetry improved at 16:28:33.  IMPACT: LOS TTBin Load 
needed to be retransmitted.  Approximately 9 minutes of telemetry loss was 
all recovered later in the pass.  DR# G101506

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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
Fax:    301-286-1729
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~