ACE Weekly 06/27/03 - 07/03/03

All ACE spacecraft subsystems are performing nominally. No maneuvers were 
executed this week. The next attitude maneuver is scheduled for 07/11/03.

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Orbit Events:

The next SEV transit will occur during the 09/01/03 - 09/23/03 
timeframe.  Expected mininum SEV angle will be 1.77 degrees.

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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. 
Release 4.1.5 was installed on 06/24/03. Testing is progressing on both 
TAPS#1 and TAPS#2.

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Automation (ROBOTT):
FOT testing of ROBOTT Release 0.1 is ongoing.  The Automation Team is 
performing testing on the Command & Control system. The first release to 
the FOT is still TBD.

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Anomalies:

DOY 03178 (6/27/2003) - ACE Anomaly Report #S03-0013 - SSCPAP5V Yellow Low 
Limit Violation.
At 17:32:02, SSCPAP5V violated its yellow low limit at a value of 4.208. It 
returned within high/low limits at 17:32:39.  Notified Jim Raines via phone 
and email.  IMPACT:  Unknown at this time.

DOY 03179 (6/28/2003) - ACE Anomaly Report #G03-0055 - GDS 26m (DSS-16) 
SFDU Bit Rate Not Correct
On DOY 179, the pass started with ACE transmitting telemetry at the 498 bps 
data-rate (14:11:31-14:24:51).  DSS-16 was correctly processing the 
telemetry, but the SFDU Bit Rate gave a value of 87648.  The ACE MOC ground 
software uses the SFDU Bit Rate for the clock calibration calculations and 
our clock calibration was wrong for DOY 180.  The SFDU Bit Rate problem had 
been fixed in delivery 3.1 of the 26m Upgrade software.  And the SFDU Bit 
Rate had the correct values during the demos in October 2002.  But this has 
been the first time we've used the 26m Upgrade equipment at 498 bps since 
it was transitioned on 03/24/2003 (DOY 083 2003).   IMPACT:   Bad clock 
calibration report sent to ACE Science Center. ASC subsequently discarded 
bad report.     DR# N101134

DOY 03183 (07/02/2003) - ACE Anomaly Report #G03-0056  Incorrect Timing 
Coefficient
While looking at the results of prepass.gen during the pass, it was noticed 
that the offset for DOY 182 was unusually high.   Notified FDF of the 
problem and had them update the timing coefficient file correctly. Copied 
the backup clock calibration to the current file and ran prepass.gen a 
second time.  IMPACT:  None, the second clock calibration report file was 
sent to and accepted by ASC.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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
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