UARS Weekly Status Report

06 May 2005




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                UARS WEEKLY STATUS REPORT - 06 MAY 2005

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***********
SOLSTICE
***********

SOLSTICE continues daylight only operations in support of the yaw 
maneuver and low power availability. Otherwise, the instrument is in 
good health gathering solar data on all available orbital tracking 
periods. On average, we received 62% of each day's data amounting to 
about 316 minutes of solar observing time per day.

***********
SUSIM
***********

SUSIM was turned off on April 16 and remains off.

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PEM
***********

Nothing received.

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HALOE 
***********

Nothing received.

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MLS
***********

Nothing received.

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HRDI
***********

Nothing received.

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MPG
***********

The MPG continues to serve as the point-of-contact for UARS
instrument operations in support of the Science Traceability
Mission of UARS.

Daily processing of instrument Daily Activity Plans continues
with no problems.

***********
CDHF
***********

Nothing received.
                  
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FOT
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                           REPORTING PERIOD

This report covers 23 April 2005 (Orbit 74519, GMT Day 113) through 
29 April 2005 (Orbit 74624, GMT Day 119).


                         SPACECRAFT OPERATION

The observatory is now in Reverse Flight (Northern Hemisphere viewing)
and   is  performing  nominally  under  two-battery  operations.   The
instrument operational changes were:


                    INSTRUMENT OPERATIONAL CHANGES

       Instrument    Time          Orbit     Comment
       SOLSTICE      113/0157      74520     POWER OFF
       SOLSTICE      114/2304      74549     POWER ON TO DAY ONLY
       HALOE         114/2304      74549     POWER OFF
       HRDI          115/1319      74558     HEATERS DISABLED


A Forward-to-Reverse Yaw Around maneuver (number 139) was successfully
executed in Orbit 7619 beginning 119/ 15:03:38Z and completing at 119/
15:40:48Z on 29 April 2005.  All instruments were in their off or
standby mode (except for SOLSTICE in day-only).  Due to the SA
position at 284 degrees, the effective night length of the spacecraft
after the maneuver was approximately 49.70 minutes.  Post maneuver
analysis of data indicate that during the Yaw Around, the end-of-night
load bus voltage was 26.40 volts and the average depths of discharge
(DODs) on Batteries 2 and 3 were approximately 20.16 and 10.25 percent
respectively.  The next (reverse-to-forward) YAW is scheduled for 30
May 2005 (DOY 150).

The beta angle ranged between the angles of 22.6 degrees to 01.6
degrees for this report period.  The beta angle is now increasing
towards a maximum angle of 38 degrees on 14 May 2005 (DOY 134).

Spacecraft battery 1, 2, and 3 performance monitoring continues.
Battery 1 remains OFF the charge relay.  Battery 2 and Battery 3 are
currently maintaining greater than 23.6 V end-of-night (EON) load bus
voltage.  Battery temperatures are stable with a temperature delta
between Battery 2 and Battery 3 of 5.14 to 4.77 degrees C.  Additional
battery performance data for each battery on 22 April 2005 and 29
April 2005 are provided in Appendix D.

The clock error ranged from 10.6 to -10.0 msec during this report
period.  Clock rate adjustments are listed in Appendix C.

All instrument and subsystem engineers were advised on the initial
excursion of ALERTS or Out-Of-Limits conditions detected by the FOT
for this report.  A summary is listed below and the details of ALERT
and Out-Of-Limits occurrences are listed in Appendix B.

    OUT-OF-LIMITS  =    00
    ALERTS         =    00

The following real-time command sheets were executed for the listed
operational element(s) during this report period (see Appendix A).

    FOT       =    09
    HALOE     =    01
    HRDI      =    01
    SOLSTICE  =    03


UARS Anomaly Reports initiated during this report period are listed in
Appendix E and summarized below.

    FOT       =    06

Three (3) Anomaly Reports remained OPEN at the end of this report
period (see Appendix E).


                        GROUND SYSTEM OPERATION

Three (3) operational support problems occurred this period.  Anomaly
Reports are included in Appendix E.

The data loss calculations are no longer being supplied by Data
Capture Facility (DCF).


                       OTHER SIGNIFICANT EVENTS


                       UARS SATELLITE OPERATIONS


This week the FOT continued to closely monitor the status of the
batteries.  The batteries maintained their VT-5 charge level and were
able to support the HALOE fulltime and SOLSTICE day-only operations
prior to the yaw.  This was almost the full operational load scheduled
with only SUSIM not powered on.  The day prior to the yaw maneuver the
battery C/D ratios began to fall to 1.00-1.02, so VT-6 was commanded.
UARS then flew through the yaw with no power problems and maintained
it VT-6 configuration into the weekend.  Next week the FOT will
consult with the NASA power branch to determine the best time to go
back to VT-5.


Also this week, the FOT continued its testing of the solar array
drive.  On Monday the B drive continued its success of Friday and ran
up and down the safe-zone at the orbital rate, which was very
promising.  The array then showed some small signs of pausing or
sticking on the last slew of the day.  During Wednesday's testing the
B-drive stalled again and the testing of the A drive continued.
Although the promise of Monday diminished during the week, this
clearly showed that if the A drive can be neutralized the B-side runs
very well.  The testing will continue with the goal of finding a way
to again neutralize the A-side.


                               MEETINGS


-None this report period



                       FUTURE SIGNIFICANT EVENTS

The next UARS Yaw slew is scheduled for 29 May 2005 (DOY 149).  This
maneuver will be a Reverse to Forward Flight maneuver (Southern
Hemisphere viewing).



Attachments:   Appendix A,      Real-time Command Sheets
               Appendix B,      Out-Of-Limits   &   ALERT  Occurrences
               Appendix C,      Clock &  Solar  Array  Rate  Corrections
               Appendix D,      UARS Battery Performance Data
               Appendix E,      UARS Anomaly Reports


                              APPENDIX A
                       REAL-TIME COMMAND SHEETS
                       Week ending 29 April 2005

ORBIT   AOS        NO.      SUBSYS      REASON
-----   ---        ---      ------      ------
74520   113/0053   05-143   SOLSTICE    REBOOT
74520   113/0157   05-144   SOLSTICE    POWER OFF
74549   114/2304   05-147   SOLSTICE    POWER ON TO DAY ONLY
74549   114/2304   05-146   HALOE       POWER OFF
74554   115/0734   05-148   OBC/CLK     CLK ADJ FR -20.6 TO 0.0 MSEC/DAY
74558   115/1319   05-149   HRDI        HEATERS DISABLED
74561   115/1822   05-150   SADDE       SADDE TESTING
74561   115/1925   05-151   TMON        TMON GROUP #49 DISABLED
74573   116/1351   05-152   SADDE       SADDE TESTING
74591   117/1815   05-153   SADDE       SADDE TESTING
74603   118/1346   05-154   MPS         VT L-5 TO VT L-6
74607   118/1922   05-155   SADDE       SADDE TESTING
74608   118/2145   05-156   OBC/CLK     CLK ADJ FR 0.0 TO -20.6 MSEC/DAY
74618   119/1343   05-157   MACS        YAW - FWD TO REV



                              APPENDIX B
                  OUT-OF-LIMITS & ALERTS OCCURRENCES
                       Week ending 29 April 2005

The following Out-Of-Limits occurrences were detected:

MNEMONIC       STATE   DESCRIPTION                ORBITS
--------       -----   -----------                ------
-None this report period.


The following ALERT occurrences were detected:

MNEMONIC     DESCRIPTION                          ORBITS
--------     -----------                          ------
-None this report period.


                              APPENDIX C
                 CLOCK & SOLAR ARRAY RATE CORRECTIONS
                       Week ending 29 April 2005

                     CLOCK DRIFT RATE ADJUSTMENTS

ORBIT          TIME                   CLOCK RATE CHANGE
-----          -----                  -----------------
74554          115/0734               CLK ADJ FR -20.6 TO 0.0 MSEC/DAY
74608          118/2145               CLK ADJ FR 0.0 TO -20.6 MSEC/DAY

                              APPENDIX D
                     UARS BATTERY PERFORMANCE DATA
                       Week ending 29 April 2005

     22 April 2005 - GMT Day 112 Beta = 26.0 deg, SA Pos = 269 deg

     DIFF V (mV)    TEMP (C)      CURR (amp)  EON V    AVE C/D  AVE
BAT  MAX/MIN        MAX/MIN       MAX/MIN     MIN      RATIO    DOD(%)
---  -------        --------      ----------  -----    -------  ------
1   -112.0/-156.8  -3.68/-4.94   +00.0/+00.0  05.9     0.00      0.0
2    291.2/ -28.0  +7.08/+5.79   +31.6/-20.0  25.3     1.03     22.95
3    257.6/-700.0  +2.60/+1.97   +20.8/-12.0  25.1     1.04     14.10

     29 April 2005 - GMT Day 119 Beta = 01.6 deg, SA Pos = 269 deg

     DIFF V (mV)    TEMP (C)      CURR (amp)  EON V    AVE C/D  AVE
BAT  MAX/MIN        MAX/MIN       MAX/MIN     MIN      RATIO    DOD(%)
---  -------        --------      ----------  -----    -------  ------
1   -50.4/-078.4   -3.68/-4.94   +00.0/+00.0  06.1     0.00      0.0
2   -67.2/-112.0   +7.74/+6.11   +33.6/-18.0  26.4     1.03     22.72
3   235.2/-700.0   +2.60/+1.34   +18.8/-10.4  26.2     1.06     11.07


     V/T LEVEL CHANGES
ORB#           AOS TIME   LVL FR-TO
-----          --------   ---------
74603          118/1346   LV5 -> LV6



                              APPENDIX E
                         UARS ANOMALY REPORTS
                       Week ending 29 April 2005

                     NEW ANOMALY REPORTS GENERATED
AR NO.    SUBSYS    ORBIT     TIME      CDS       PROBLEM/DATA LOSS
------    ------    -----     ----      ---       -----------------
05-026    SOLSTICE  74520     113/0053  N/A       SOLS TEMP LIMITS
05-023    FOT       74546     114/1928  30832     Generic Late Acquisition
05-027    FOT       74548     114/2224  39337     Data Drop Out
05-023    FOT       74553     115/0544  30832     Generic Late Acquisition
05-023    FOT       74568     116/0542  30832     Generic Late Acquisition
05-023    FOT       74589     117/1603  30832     Generic Late Acquisition

                 ANOMALY CLOSURE INFORMATION RECEIVED
AR NO.    SUBSYS    ORBIT     TIME      CDS       PROBLEM/DATA LOSS
------    ------    -----     ----      ---       -----------------
05-025    FOT       74518     112/2157  39315     Intermittent Dropouts

                ANOMALY INVESTIGATION REPORTS GENERATED
AIR NO.   SUBSYS    ORBIT     TIME      CDS       PROBLEM/DATA LOSS
------    ------    -----     ----      ---       -----------------
-None this report period.

                         OPEN ANOMALY REPORTS
AR NO.    SUBSYS    ORBIT     TIME      CDS       PROBLEM/DATA LOSS
------    ------    -----     ----      ---       -----------------
05-023    FOT       See List  Apr 05    30832     Generic Late Acquisition
05-026    SOLSTICE  74520     113/0053  N/A       SOLS TEMP LIMITS
05-027    FOT       74548     114/2224  39337     Data Drop Out