UARS Weekly Status Report

03 May 2002




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                UARS WEEKLY STATUS REPORT -  3 May 2002

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

SOLSTICE continues under day only operations due to low power
conditions. We are performing default solar observations during this
time.

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

SUSIM successfully performed its daily mid-resolution and MgII
solar scans during periods of predicted UARS telemetry.

On May 20, Dr. Patrick Crane is leaving the SUSIM group to take a
scientist position with the NRL Remote Sensing Division.  Since 1993,
Pat has worked to help to operate and understand the SUSIM instrument
and improve its data.  We wish thank him for his contributions and
wish him the best of luck in his new endeavors.

***********
ACRIM
***********

Nothing received.

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

Nothing received.

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

Nothing received.

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

Nothing received.

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

Nothing received.

***********
WINDII
***********

Nothing received.

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

The MPG attended the UARS Status Review Meeting on 2 May 2002. 
Review on 21 March 2002.

The MPG continues to serve as the point-of-contact for UARS
instrument operations to support re-engineering of the UARS
Mission Operations Concept to develop capabilities for the
Science Traceability Mission.
 
Daily processing of instrument Daily Activity Plans continues
with no problems.

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

Nothing received.
                  
***********
FOT
***********

                           REPORTING PERIOD

This report covers 20 April 2002 (Orbit 57995, GMT Day 110) through 26
April 2002 (Orbit 58099, GMT Day 116).

                         SPACECRAFT OPERATION

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

                    INSTRUMENT OPERATIONAL CHANGES

       Instrument    Time          Orbit     Comment
       PEM           115/0049      58070     AXIS 1,2 POWER OFF
       PEM           115/0049      58070     ZEPS / HEPS DAY-ONLY
       WINDII        115/1327      58078     POWER ON

The  beta  angle ranged between the angles of 29.45 degrees  to  53.74
degrees  for  this  report period.  The beta angle is  now  increasing
towards a maximum angle of 73 degrees on 03 May 2002 (DOY 123).

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 23.8 V end-of-night (EON) load  bus
voltage.   Battery  temperatures are stable with a  temperature  delta
between Battery 2 and Battery 3 of 0.96 to 1.27 degrees C.  Additional
battery  performance data for each battery on 19  April  2002  and  26
April 2002 are provided in Appendix D.

The  clock  error  ranged from -9.8 to 10.3 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            =    03
    PEM AXIS       =    03
    WINDII         =    03

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

    FOT       =    0

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

TRANSPONDER FREQUENCIES:
    Transponder A:  01/333  - 2287.496855
    Transponder B:  02/043  - 2287.498879

                        GROUND SYSTEM OPERATION

Zero  (0) 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

The  FOT is in the process of implementing some minor changes  to  the
Eclipse  system  to  help optimize operations.  All  of  the  existing
documentation is also in the process of being updated to  reflect  the
new  ground  system  nomenclature.  A few new  SOPs  have  yet  to  be
written, while the handful that have already been written need  to  be
finalized and signed off on.

A  discussion regarding the UARS power issues will be held at the UARS
Monthly meeting on 02 May 2002.  The purpose of this discussion is  to
determine a course of action that will improve the power situation for
the summer yaw maneuvers.  Options include turning off the instruments
early and delaying their turn on, rolling the spacecraft, driving  the
array or changing the V/T limit on the batteries.

                               MEETINGS

None this report period.

                       FUTURE SIGNIFICANT EVENTS

The  next UARS Yaw slew is scheduled for 23 May 2002 (DOY 143).   This
maneuver  will  be  a  Forward to Reverse  Flight  maneuver  (Northern
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 26 April 2002

ORBIT   AOS        NO.      SUBSYS      REASON
-----   ---        ---      ------      ------
58017   111/1152   02-141   OBC/CLK     CLK ADJ FR 0.0 TO 20.6 MSEC/DAY
58035   112/1657   02-142   OBC/CLK     CLK ADJ FR 20.6 TO 0.0 MSEC/DAY
58070   115/0049   02-143   PEM         AXIS 1,2 POWER OFF
58070   115/0049   02-144   PEM         ZEPS / HEPS DAY-ONLY
58078   115/1327   02-145   WINDII      POWER ON
58084   115/2345   02-146   OBC/CLK     CLK ADJ FR 0.0 TO 20.6 MSEC/DAY
58094   116/1437   02-147   WINDII      RESET TO CLEAR ERROR E06
                                   
                                   
                                   
                              APPENDIX B
                  OUT-OF-LIMITS & ALERTS OCCURRENCES
                       Week ending 26 April 2002

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 26 April 2002

                     CLOCK DRIFT RATE ADJUSTMENTS

ORBIT          TIME                   CLOCK RATE CHANGE
-----          -----                  -----------------
58017          111/1211               CLK ADJ FR 0.0 TO 20.6 MSEC/DAY
58035          112/1659               CLK ADJ FR 20.6 TO 0.0 MSEC/DAY
58084          115/2348               CLK ADJ FR 0.0 TO 20.6 MSEC/DAY


                              APPENDIX D
                     UARS BATTERY PERFORMANCE DATA
                       Week ending 26 April 2002


     19 April 2002 - GMT Day 109 Beta = 25.85 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  +728.0/+728.0  -3.16/-4.38   +0.0/ +0.0    0.0     0.000     0.0
2   +11.2/ -89.6  +5.14/+4.18  +29.2/-15.2   24.8     1.030    20.7
3   +22.4/-33.6   +4.50/+2.91  +28.4/-15.2   24.8     1.020    20.4


     26 April 2002 - GMT Day 116 Beta = 53.74 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  +728.0/+728.0  -3.16/-4.38   +0.0/ +0.0    0.0      0.000     0.0
2   +11.2/-100.8  +5.14/+3.87  +24.0/-15.2   24.8      1.040    20.2
3   +22.4/-56.0   +3.87/+2.91  +24.0/-15.2   24.8      1.040    19.9

     V/T LEVEL CHANGES
ORB#           TIME       LVL FR-TO
-----          ----       ---------
-no changes    V/T 5




                              APPENDIX E
                         UARS ANOMALY REPORTS
                       Week ending 26 April 2002

                     NEW ANOMALY REPORTS GENERATED
AR NO.    SUBSYS    ORBIT     TIME      TTR       PROBLEM/DATA LOSS
------    ------    -----     ----      ---       -----------------
-None this report period


                 ANOMALY CLOSURE INFORMATION RECEIVED
AR NO.    SUBSYS    ORBIT     TIME      TTR       PROBLEM/DATA LOSS
------    ------    -----     ----      ---       -----------------
02-025    FOT       See List  Apr 13    N/A       Generic Late Acquisition


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


                         OPEN ANOMALY REPORTS
AR NO.    SUBSYS    ORBIT     TIME      TTR       PROBLEM/DATA LOSS
------    ------    -----     ----      ---       -----------------
02-004    SOLSTICE  56883     036/0050  N/A       Solstice in Wrong Mode
02-023    FOT       57767     094/2027  24285     Early LOS on OMNI Pass
02-024    FOT       57783     095/2209  24285     SOLSTICE INOPS in Day