UARS Weekly Status Report

26 April 2002




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                UARS WEEKLY STATUS REPORT - 26 Apr 2002

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

Nothing received.

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

SUSIM began its first scans after yaw on April 17.  Since then,
the instrument has performed its daily mid-resolution and MgII
solar scans during periods of predicted UARS telemetry.

Ed Esfandiari has written IDL routines to automatically generate
(on the fly) the RSS mode DCL runsteams needed for SUSIM
reprocessing.  Using these tools, we were able to reprocess at
level-1 more than 1000 days of SUSIM UARS data in just 2 days!  We
then estimate that we will be able reprocess the entire SUSIM
dataset from a low level 1 to level 3BS in about a week.

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

Nothing received.

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

     PEM continues to receive NMC data files from NOAA.  No problems have
been encountered.

     PEM support of the UARS Traceability Mission for the TIMED mission has
been organized with the GVUI team.  Predicted TIMED-UARS conjunctions from
the high geographic latitudes were compared with the expected magnetic position
and the PEM climatology.  Positional and anticipated precipitation flux 
information showed that the expected electron precipitation as a function of 
magnetic activity had the highest probably of a successful conjunction on
April 19.  Continued monitoring has shown changes in conjunction times.  For
conjunctions within 300 km, there are now 4 times shown:

Contact #    Date    Day  Time   Geo Lat   ILAT   MLT   Hemisphere
                                  (deg)   (deg)   (hr)
    1      April 18  108  21:30   56.87   54.43   2.96  North
    2      April 18  108  22:18  -56.89   66.06   6.07  South
    3      April 23  113  14:56   56.98   53.06  20.04  North
    4      April 23  113  15:44  -56.98   47.76   9.11  South


Contact times have remained about the same in geographic position, but not in
magnetic position.  The MLT of contact 3 has changed the most.  Definitive UARS
orbit positions will determine the final locations.


*Beginning of power orbit day (PEM activation): array current >5 amps, array 
     voltage >53.5 volts, and battery current >2.0 amps.  
 End of power orbit day (PEM deactivation): time in power orbit day >4 minutes,
     array current <9 amps, and battery currents <0.2 amps.
 Power orbit day variation: ~39-40 min at yaw to ~50-51 min at maximum beta.

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

Nothing received.

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

Nothing received.

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

Nothing received.

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

Nothing received.

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

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 13 April 2002 (Orbit 57889, GMT Day 103) through 19 April
2002 (Orbit 57994, GMT Day 109).

                         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           106/1340      57943     Power ON
       SUSIM         107/1338      57958     Power ON START
       SUSIM         107/1437      57958     Power ON CONTINUED
       SUSIM         108/1254      57977     Power ON COMPLETED
       PEM           108/1336      57871     Power ON
       HALOE         109/1436      57988     Power ON
       HALOE         109/2011      57992     Power ON COMPLETED

A Reverse-to-Forward Yaw Around maneuver (number 108) was successfully
executed  in  Orbit  57899 beginning 103/16:10:22Z and  completing  at
103/16:47:32Z on 13 April 2002.  The SOLSTICE instrument  was  in  day
only  and  all  other instruments were in their off  or  standby  mode
(including HRDI and PEM).  Due to the SA position at 269 degrees,  the
effective  night  length  of the spacecraft  after  the  maneuver  was
approximately  56.1 minutes.  Post maneuver analysis of data  indicate
that  during  the  Yaw Around, the end-of-night load bus  voltage  was
24.30 volts and the average depths of discharge (DODs) on Batteries  2
and  3  were approximately 21.09 and 20.62 percent respectively.   The
next (forward-to-reverse) YAW is scheduled for 23 May 2002 (DOY 143).

The  beta  angle  ranged between the angles of 1.58 degrees  to  25.85
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 1.59 degrees C.  Additional
battery  performance data for each battery on 12  April  2002  and  19
April 2002 are provided in Appendix D.

The  clock  error  ranged from -14.0 to 13.1 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          =    02
    PEM AXIS       =    02
    SUSIM          =    03

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

    FOT       =    1

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

One  (1)  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 successfully executed the yaw maneuver on 13 April 2002  from
the  new  Eclipse  ground system.  There were no problems  encountered
with  the  new system during the maneuver.  The instrument power  offs
and  turn  ons  went well also with only a few minor  timing  problems
which  can easily be remedied before the next instrument configuration
change.  The Eclipse system appears to have passed its test during the
maneuver  period and only a few minor modifications  are  left  to  be
completed.  Once again the FOT would like to thank all those who had a
part in implementing the new ground system.

                               MEETINGS

The FOT did not attended any meetings this week.

                       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 19 April 2002

ORBIT   AOS        NO.      SUBSYS      REASON
-----   ---        ---      ------      ------
57896   103/1136   02-126   OBC/CLK     CLK ADJ FR 20.6 TO 0.0 MSEC/DAY
57899   103/1539   02-127   MACS        TAM TO MONITER MODE
57899   103/1539   02-128   MACS/OBC    YAW SCRIPT
57899   103/1627   02-129   MACS        TAM ALIGN/UPDATE MODE
57901   103/1851   02-130   OBC/CLK     CLK ADJ FR 0.0 TO -20.6 MSEC/DAY
57925   105/0939   02-131   OBC/CLK     CLK ADJ FR -20.6 TO 0.0 MSEC/DAY
57932   105/1958   02-132   OBC/CLK     CLK ADJ FR 0.0 TO 20.6 MSEC/DAY
57943   106/1340   02-133   PEM AXIS    POWER ON
57947   106/1846   02-134   OBC/CLK     CLK ADJ FR 20.6 TO 0.0 MSEC/DAY
57956   107/1018   02-135   OBC/CLK     CLK ADJ FR 0.0 TO -20.6 MSEC/DAY
57958   107/1338   02-136   SUSIM       POWER ON START
57958   107/1437   02-136   SUSIM       POWER ON CONTINUED
57977   108/1254   02-136   SUSIM       POWER ON COMPLETED
57978   108/1336   02-137   PEM         POWER ON
57988   109/1436   02-139   HALOE       POWER ON
57992   109/2011   02-140   HALOE       POWER ON COMPLETED
                                   
                                   
                                   
                              APPENDIX B
                  OUT-OF-LIMITS & ALERTS OCCURRENCES
                       Week ending 19 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 19 April 2002

                     CLOCK DRIFT RATE ADJUSTMENTS

ORBIT          TIME                   CLOCK RATE CHANGE
-----          -----                  -----------------
57896          103/1140               CLK ADJ FR 20.6 TO 0.0 MSEC/DAY
57901          103/1839               CLK ADJ FR 0.0 TO -20.6 MSEC/DAY
57925          105/0945               CLK ADJ FR -20.6 TO 0.0 MSEC/DAY
57932          105/2010               CLK ADJ FR 0.0 TO 20.6 MSEC/DAY
57947          106/1846               CLK ADJ FR 20.6 TO 0.0 MSEC/DAY
57956          107/1023               CLK ADJ FR 0.0 TO -20.6 MSEC/DAY


                              APPENDIX D
                     UARS BATTERY PERFORMANCE DATA
                       Week ending 19 April 2002


     12 April 2002 - GMT Day 102 Beta = 7.14 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/-134.0 +4.50/+3.87  +27.8/-15.8  25.0     1.010    20.6
3   +22.4/-22.4  +3.55/+2.60  +26.7/-15.8  25.0     1.010    20.3


     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

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




                              APPENDIX E
                         UARS ANOMALY REPORTS
                       Week ending 19 April 2002

                     NEW ANOMALY REPORTS GENERATED
AR NO.    SUBSYS    ORBIT     TIME      TTR       PROBLEM/DATA LOSS
------    ------    -----     ----      ---       -----------------
02-025    FOT       57899     103/1627  14170     Generic Late Acquisition


                 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