UARS Weekly Status Report

23 APR 1999




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                UARS WEEKLY STATUS REPORT - 23 APR 1999

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

SOLSTICE continues to operate normally, collecting solar data on all 
available orbital tracking periods and stellar calibration observations, 
whenever possible.

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

NOTHING RECEIVED.

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

NOTHING RECEIVED.

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

HALOE continues successful operations with all engineering parameters
within nominal operating range.  Science data results are of excellent quality.

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

NOTHING RECEIVED.

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

NOTHING RECEIVED.

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

WINDII performed normally during its operating period of
April 13 - 19. Its next operation is scheduled for April
25 - 29. Data reprocessing is proceeding well, and is 
up to day 359. 

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

Routine processing of instrument Daily Activity Plans continues  
with no problems.  The MPG continues to assist the Project 
Scientist with the scheduling of instrument operations. 

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

The CDHF Y2K end to end testing is scheduled for Thursday April 29, 1999.
                               
The CDHF processed current day data through level 3 for all active
instruments. Additionally, CDHF personnel reprocessed: (R)= Requested
   (C) = Complete, (F)= Failed  (L) = Days remaining to reprocess.
         1 day  HRD (4.4)  PROD (L1-L3)         (1R-1C=0L)
        50 days PEM (3.32) PROD (OA-L2)         (760R-528C-1F=231L)
       131 days WIN (5.11) PROD (LOG)           (2014R-1192C=822L)
        71 days WIN (5.11) PROD (L1-L3)         (2014R-263C=1751L)

The CDHF plans to start testing CLAES V7.0 formal software delivery.

SOLSTICE Wall Clock time increase. Analyze SOLSTICE debug step 2 test
production job for "general unrecoverable error".
                  
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FOT
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REPORTING PERIOD


This report covers 10 April 1999 (Orbit 41410, GMT Day 100) through 16 April 
1999 (Orbit 41513, GMT Day 106).


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
                MLS       100/2314      41424     Off
               ACRIM      101/0200      41426     On
               SUSIM      101/1257      41433     On
                PEM       102/2242      41454     AXIS-1 Off
               WINDII     103/0208      41456     On
                PEM       107/0040      41515     AXIS On

The beta angle ranged between the angles of 41.4 degrees to 46.5 degrees 
for this report period.  The beta angle is now increasing toward a maximum 
angle of 2.9 degrees on 30 April 1999 (DOY 120).

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 1.2 to 1.6 degrees C.  Additional battery performance data 
for each battery on 09 April 1999 and 16 April 1999 are provided in 
Appendix D.


The clock error ranged from -10.9 to 11.7 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.

%     ALERTS         =     00
%     OUT-OF-LIMITS  =     01

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

%     FOT     05
%     ACRIM   01
%     MLS     01
%     PEM     03
%     SUSIM   01
%     WINDII  01

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

%     FOT     04

One (1) Anomaly Report remained OPEN at the end of this report period (see 
Appendix E).

TRANSPONDER FREQUENCIES:
          Transponder A:  99/054  -  2287.496923
          Transponder B:  99/055  -  2287.498750


GROUND SYSTEM OPERATION

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


The data loss calculations supplied by Data Capture Facility (DCF) from 
mission start through UTC Day 99/105 show the observatory data loss to be 
22 hours, 47 minutes, 46.804 seconds (an increase of 41.102 seconds since 
last report period).  This is a 0.0345 percent data loss which equals a 
99.9655 percent data capture for the mission.

The increase of 41.102 seconds occurred over four (4) days:

7 0.576 seconds on Day 100 due to data hit,
7 30.112 seconds on Day 102 due to degraded data (reason unknown),
7 1.408 seconds on Day 103 due to data hits, and
7 9.024 seconds on Day 105 due to insufficient overlap.

The FOT is still awaiting the delivery of the 8-week Ground Track Y2K test 
file from FDF.  This file was expected to be delivered this week, but was 
not received as of the end of this reporting period.

A new version of RTS 31 was built on 15 April.  The purpose of the new RTS 
was to further refine the PMON controlled operations of the PEM instrument.  
From the data observed by the FOT after the uplink of this latest RTS, it 
appears that the PEM is finally operating as desired via PMON.

The FOT was required to delete and re-add all of their confirmed TDRS 
events spanning days 106 through 115 due to an NCC database problem.  This 
was a lengthy task, as all of the new events had to be built to reflect the 
exact AOSs and LOSs of the original events.


OTHER SIGNIFICANT EVENTS

UARS SATELLITE OPERATIONS

The FOT and the PEM team have defined an RTS that successfully operates PEM 
EP6 under PMON control.  On Wednesday, 14 April, PDB-10 was disabled and 
its three command added to the beginning of RTS-31 and the EP6 responded 
correctly.

The FOT continues to investigate the feasibility of a new PMON action to 
change battery V/T curves based on loading to mitigate battery risks in sun 
pointing safehold.


YEAR 2000 OPERABILITY SUPPORT - No change


UARS PROPULSION MODULE B/D THRUSTER LINE FILL - No change


MEETINGS

FOT supported the weekly IMOC meeting on 14 April 1999. Tim Christy spoke 
about the Blossom Point project that he used to work on.  It was a Navy 
Research Lab multi-satellite operation, so it gave us some more information 
on how to conceptualize the IMOC.

FOT attended the monthly battery teleconference.  The next battery 
teleconference is scheduled for Tuesday, 11 May 1999 at 1:00 PM EDT.


FUTURE SIGNIFICANT EVENTS

The next UARS Yaw Around Maneuver (reverse-to-forward) is scheduled for 30 
April 1999 (DOY 120).


PERSONNEL CHANGES

John Speer has announced his intent to retire effective 30 April 1999.

Pete Thomas, Offline Engineer, announced his resignation effective 21 April 
1999 to pursue other opportunities.


Attachments:  Appendix A,  Real-time Commands 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 16 April 1999

ORBIT        AOS         NO.     SUBSYS         REASON
-----        ---        ---     ------         -------  
41417     100/1204     99-130     OBC     Clk Adj fr 0.00 to 20.6 msec/day
41421     100/1732     99-131     PMON    Enabled Comp Htr 18 A&B sides
41424     100/2314     99-132     MLS     Power OFF
41426     101/0200     99-133     ACRIM   Power ON
41433     101/1257     99-134     SUSIM   Power ON
41436     101/1806     99-131     PMON    Disable Comp Htr 18 B side
41454     102/2242     99-135     PEM     Power OFF AXIS1
41454     102/2242     99-136     OBC     Clk Adj fr 20.6 to 0.00 msec/day
41456     103/0208     99-137     WINDII  Power ON
41482     104/1956     99-138     OBC     Clk Adj fr 0.00 to 20.6 msec/day
41483     104/2135     99-139     PEM     RTSPEM Test
41515     107/0040     99-107     PEM     AXISPower ON

_______________________________________________________________

                               APPENDIX B
                  OUT-OF-LIMITS & ALERTS OCCURRENCES
                      Week ending 16 April 1999

MNEMONIC       STATE     DESCRIPTION                       ORBITS
---------      -----     ------------                      ------
SORLBXTMPR      Y-LO     Logic_Box Temperature     continuous


The following ALERT occurrences were detected:

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

_______________________________________________________________

                              APPENDIX C
                 CLOCK & SOLAR ARRAY RATE CORRECTIONS
                       Week ending 16 April 1999

                      CLOCK DRIFT RATE ADJUSTMENTS

     ORBIT              TIME                 CLOCK RATE CHANGE
     -----              ----                 -----------------
     41417     100/12:11 (10 Apr 99)     from 00.0 to 20.6 msec/day
     41454     102/22:50 (12 Apr 99)     from 20.6 to 00.0 msec/day
     41482     104/20:05 (14 Apr 99)     from 00.0 to 20.6 msec/day


_______________________________________________________________


                             APPENDIX D
                    UARS BATTERY PERFORMANCE DATA
                       Week ending 16 April 1999


     09 Apr 1999 - GMT Day 099 Beta = 41.4 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   -44.8/-67.2  -3.05/-4.31   +0.0/ +0.0    16.6    0.000    0.0
2  +100.8/0.0    +6.11/+5.15  +28.8/-15.2    24.5    1.022   21.9
3   +22.4/-50.4  +5.15/+3.87  +28.4/-16.0    24.5    1.025   21.8


     16 Apr 1999 - GMT Day 092 Beta = 46.5 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   -56.0/-78.4   -3.05/-4.31  +0.0/ +0.0    16.6    0.000    0.0
2   +78.4/-5.6    +6.44/+4.51 +27.2/-16.0    24.3    1.019   22.1
3   +33.6/-33.6   +5.15/+3.87 +27.2/-16.8    24.2    1.023   21.8


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



                               APPENDIX E
                         UARS ANOMALY REPORTS
                      Week ending 16 April 1999


                     NEW ANOMALY REPORTS GENERATED
  AR NO.  SUBSYS   ORBIT      TIME       TTR      PROBLEM/DATA LOSS
  ------  ------   -----      ----       ---      -----------------
99-017     FOT     41421     100/1732     N/A     File Transfer PENDING
99-016     FOT     41437     101/1915     14170   Generic Late Acquisition
99-016     FOT     41473     104/0532     14170   Generic Late Acquisition
99-018     FOT     41496     105/1918     20759   Tlm hit I & Q 


                 ANOMALY CLOSURE INFORMATION RECEIVED
  AR NO.  SUBSYS   ORBIT     TIME        TTR      PROBLEM/DATA LOSS
  ------  ------   -----     ----        ---      -----------------
99-017     FOT     41421     100/1732     N/A     File Transfer PENDING
99-016     FOT     41437     101/1915     14170   Generic Late Acquisition
99-016     FOT     41473     104/0532     14170   Generic Late Acquisition
99-018     FOT     41496     105/1918     20759   Tlm hit I & Q 

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


                         OPEN ANOMALY REPORTS
  AR NO.   SUBSYS   ORBIT    TIME       TTR       PROBLEM/DATA LOSS
  ------   ------   -----    ----       ---       -----------------
99-016      FOT     see list   Apr 99   14170     Generic Late Acq

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