ACE Weekly 05/30/03 - 06/05/03

All ACE spacecraft subsystems are performing nominally. An attitude 
maneuver was successfully executed on 05/30/03. The next attitude maneuver 
is schedule for 06/06/03.

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Orbit Events:

Currently in SEV transit:

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

============================================================================
OCRs Executed:

EPAM-002

EPAM-003

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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. Release 4.1.3 was 
installed on 05/27/03 but it was determined that a re-release was required 
because there were some installation problems on both systems (TAPS#1 and 
TAPS#2). Release 4.1.4 was installed on 05/30/03.  A problem was found on 
TAPS #1 and a re-installation of Release 4.1.4 was required on TAPS #1 on 
06/04/03.

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Automation (ROBOTT):

Testing of the Offline and HSM systems is progressing. Testing by the 
Automation team for Command and Control is still paused due to testing at 
WIND. The first release of Command and Control to the FOT is still TBD.

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

Day 03150 (05/30/2003) ACE Anomaly Report #S03-0009 - Mnemonic 
S3DPU_CONV_SEC_I Red Limit Violation
At 16:02:20 and at 16:02:32, the S3DPU_CONV_SEC_I violated the red high 
limit with a value of 443.186.  Notified Mark Popecki.  The FOT informed 
him that there was an X1 class solar flare and an associated CME headed 
straight for Earth.  M. Popecki believes that these event messages are due 
to the solar activity.  He asked the FOT to check the values for the 
SSDIDLECTR which had dropped down as low as 27 during the pass.  For most 
of the pass, the idle counter was around 42.  This in an indication that 
the S3DPU is collecting a lot of data.  Nominally,  when there is no solar 
activity, the idle counter is around 80.  IMPACT:  NONE

Day 03150 (05/30/2003) ACE Anomaly Report #G03-0043 - GDS 26m 
(DSS-16)  Dropped Blocks
At 16:15, the FOT informed DSS-16 of degraded data.  DSS-16 stated that 
everything was fine on their end.  JPL COM was notified of the problem and 
stated they could see dropped blocks but no data hits.  At 16:22, JPL COM 
reported that 10 blocks were dropped between 16:05 - 16:16.   IMPACT: 
None.  Data was recovered.  DR# N101062

Day 03150 (05/30/2003) ACE Anomaly Report #G03-0044 -  Problem with 
Attitude Determination System (ADS) - String 1
When FDF tried to start the ADS software on String 1, it would not 
start.  FDF tried numerous times with the same result.  One of the times, 
ADS was started, but no data was written to the correct 
files.  IMPACT:  Since this was a maneuver day, String 2 had to be used by 
FDF as the primary for obtaining an attitude solution, and String 3 was 
used as the backup.  There were also problems on String 3 (Reference AR 
G03-0045).

Day 03150 (05/30/2003) ACE Anomaly Report #G03-0045 -  Problem with 
Attitude Determination System (ADS) - String 3
When the calc_att script is run on String 3, the output is different than 
expected.  Calc_att on String 2 gives the correct output and this file was 
used for comparison.  Since string 3 needed to be used as the backup for 
the maneuver (Ref. AR 03-0044), FDF brought up ADS using just the 
Deterministic, not the Kalman Filter.  The ace.startup.ads.ops file in 
/home/ace/relx.ops/obj_hp/setup/ had been changed when testing was being 
performed.  This file was never changed back to the original.  On Day03152 
(Monday), the correct ace.startup.ads.ops file was copied from String 1 to 
String 3.

Day 03154 (06/03/2003) ACE Anomaly Report #G03-0046 - GDS 26m 
(DSS-16)  Command Subcarrier Left ON
At 15:45 FOT noticed that the command subcarrier was ON from looking at the 
CLCW_NO_BIT_LOCK            mnemonic.  DSS-16 set the subcarrier to 
OFF.  When FOT tried a NO-OP command to verify command capability the 
command was not accepted by the SC.  FOT had DSS-16 reconfigure to the 
NOMINAL configuration.  Command capability was subsequently verified by the 
FOT.  IMPACT:  None at this time, however subcarrier left ON is non-nominal 
configuration.  DR# G102829

Day 03154 (06/03/2003) ACE Anomaly Report #G03-0047 - GDS 26m 
(DSS-16)  Telemetry Dropout
At 17:06 telemetry went offline and stopped flowing from DSS-16.  AT 17:17 
DSS-16 informed us that they were having problems with the CS SCP for all 
out going data and should be back up within ~5 minutes.  AT 17:29 the DSN 
OPS CHIEF called and stated that they were having problems with the LAN out 
at JPL, no ETA at to when it would be fixed.  At 17:36 telemetry came back 
online.  Telemetry was offline from 17:06 to 17:36.   IMPACT:  None.  All 
data was subsequently recovered.  DR# G102830

Day 03156 (06/05/2003) ACE Anomaly Report #S03-0010 - Wrong EPAM Command
FOT was contacted by David Lohr, EPAM Instrumenter, to perform OCR 
EPAM-002.  Command "EPAM_DATA CMD_DATA=h'6200' " was sent to the Spacecraft 
and was verified on the Spacecraft.  After ~2-5 minutes, David Lohr 
notified us that he did not see the expected result.  After further 
investigation by the EPAM instrumenters, it was determined that first 
command had the incorrect hex value.  The instrumenters then submitted a 
second OCR to send the correct command.  However, that command did not have 
the expected result either.  The FOT launched their own investigation and 
recalled that the EPAM instrumenters had performed this same activity back 
in 1998.  Investigation revealed that the same command as listed above was 
sent then and did not achieve the desired result.  The FOT looked at the 
command build and found that the ground software was adding an additional 
parity bit which resulted in a NO-OP command being sent. The FOT notified 
the instrumenter of its findings and what the correct command should be. 
The instrumenter has concurred and the correct command is expected to be 
sent Monday 6/9/2003 (DOY 160).


~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Glen A. Miller
ACE Flight Operations Observatory Engineer
Honeywell Technology Solutions Inc.
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
Email: gamiller@pop500.gsfc.nasa.gov
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~