UARS Weekly Status Report

08 JANUARY 1999




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                UARS WEEKLY STATUS REPORT - 08 JAN 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. The CDHF has completed SOLSTICE version 10 re-processing 
and is now running the current processing stream only.

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

Nothing received.

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

     PEM is now under PMON control!  OBC activation tests of the high energy
particle spectrometer (HEPS -- particles greater than 30 keV) were declared 
successful on UARS day 2670 (January 2, 1999).  Beginning this date, all PEM 
activations should yield correct scientific data; however, data generated from 
the HEPS subsystem between December 17, 1998 and January 1, 1999 should be 
considered invalid and not used.  The PEM team would like to thank the FOT, and
in particular Peter Thomas, for their work and efforts related to obtaining a
correct OBC activation procedure for the HEPS subsystem.

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

HALOE was powered off on January 6th for the upcoming yaw after
successfully operating since December 17, 1998.  All engineering parameters
were nominal and the science data products continue to be of excellent quality.

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

The instrument is now off as scheduled.

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

Nothing received.

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

Nothing received.

***********
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. 

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

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

REPORTING PERIOD


This report covers 26 December 1998 (Orbit 39838, GMT Day 360) through 01 
January 1999.

The observatory is now in Forward Flight (Southern Hemisphere viewing) with 
a +0.5 degree Roll (cold side down) and is performing nominally under two-
battery operations.  The instrument operational changes were:

               INSTRUMENT OPERATIONAL CHANGES

        Instrument      Time       Orbit     Comment
           MLS        363/2312     39896     Off
          ACRIM       363/2312     39896     On
          SUSIM       364/0015     39897     On
           PEM        365/1626     39922     Testing 

A summary of Instrument operations supplied by the Mission Planning Group 
for the month December 1998 is contained in Appendix F, UARS Instrument 
Operations Summary.

The beta angle ranged between 32.2 degrees to 29.9 degrees for this report 
period. The beta angle is now increasing toward a minimum angle of +1.0 
degrees on 11 January 1999 (DOY 011).

UARS Flight Software Time was adjusted consistent with the United States 
Naval Observatory (USNO) Time Service announcement advising that the 
International Earth Rotation Service (IERS) will retard UTC time by 1.0 
second at the end of December 1998. This meant the addition of one leap 
second as the last second of 1998.

The PEM Instrument automated turn-on procedure for Day-Only Operation has 
been completed and successfully tested in orbit.  HEPS-1 and HEPS-2 are 
working (HEPS-3 will not be operated day only).

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 1.0 to 1.3 degrees C.  Additional battery performance data 
for each battery on 25 December 1998 and 01 January 1999 are provided in 
Appendix  D.

The clock error ranged from 10.3 to -11.4 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         =     05
%     OUT-OF-LIMITS  =     02

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       03
%     PEM       09
%     SOLSTICE  03
%     SUSIM     01

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

%     FOT       01

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


TRANSPONDER FREQUENCIES:
     Transponder A:  98/286  -  2287.496936
     Transponder B:  98/300  -  2287.498964


GROUND SYSTEM OPERATION

One (1) 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 98/365 show the observatory data loss to be 
21 hours, 40 minutes, 58.964 seconds (an increase of 30.432 seconds since 
last report period).  This is a 0.0340 percent data loss which equals a 
99.9660 percent data capture for the mission.

The increase of 30.432 seconds occurred over two (2) days:

7 0.512 seconds on Day 362 due to data hit; and
7 29.920 seconds on Day 365 due to data hit, year change, leap second 
adjust.


OTHER SIGNIFICANT EVENTS

UARS SATELLITE OPERATIONS

The SSPP temperature stability is being analyzed.  It appears that since 
SOLSTICE is cycling, the usual amount of heat is not being generated and 
along with the other SSPP instruments, getting slightly colder.  
Investigation revealed a problem in operation of Compensation Heater 18B.  
Operational changes were implemented but sufficient operational time to 
evaluate the thermal effect has not elapsed.

The FOT is investigating 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

Planning continues for the simulator testing.


UARS RE-ENGINEERING - TELEMETRY PROCESSING - No change


MEETINGS

None


FUTURE SIGNIFICANT EVENTS

The next UARS Yaw Around Maneuver is scheduled for scheduled for 11 January 
1999.

The next annular solar eclipse will occur on 16 February 1999 over the 
Indian Ocean, Australia and the South Pacific Ocean.


PERSONNEL CHANGES

none


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 F,   UARS Instrument Operations Summary




                               APPENDIX A
                       REAL-TIME COMMAND SHEETS
                      Week ending 01 January 1999

ORBIT      AOS          NO.    SUBSYS       REASON
-----      ---          ---    ------       -------  
39846     360/1416    98-516   MLS       Scan Act OFF
39851     360/2251    98-517   MLS       Scan Act ON
39872     362/0740    98-518   OBC       Clk Adj fr 0.00 to 20.6 msec/day
39878     362/1757    98-519   PSU       Enabled Comp Htr 18 A&B sides
39895     363/2039    98-520   SOLSTICE  SOLSTICE RTSs
39896     363/2312    98-521   MLS       Power OFF
39896     363/2312    98-522   ACRIM     Power ON
39897     364/0015    98-523   SUSIM     Power ON
39900     364/0420    98-524   OBC       Clk Adj fr 20.6 to 0.00 msec/day
39900     364/0518    98-525   PSU       Comp HTR 18 ON BOTH
39901     364/0707    98-526   SOLSTICE  SOLSTICE RESET
39903     364/0932    98-526   SOLSTICE  SOLSTICE RESET
39907     364/1550    98-537   PSU       Comp HTR 18 ON BOTH
39921     365/1403    98-528   PEM       Revised DAY-ONLY sequences
39922     365/1626    98-529   PEM       DAY-ONLY TEST-1
39923     365/1735    98-530   PEM       DAY-ONLY TEST-2
39924     365/1949    98-531   PEM       DAY-ONLY TEST-3
39925     365/2126    98-532   PEM       DAY-ONLY TEST-4
39927     001/0025    99-001   PEM       PMON/PEM Test 6
39928     001/0206    99-002   PEM       PMON/PEM Test 7
39929     001/0346    99-003   PEM       PMON/PEM Test 8
39930     001/0528    99-004   PEM       PMON/PEM Test 9

_______________________________________________________________

                               APPENDIX B
                  OUT-OF-LIMITS & ALERTS OCCURRENCES
                      Week ending 01 January 1999

MNEMONIC         STATE      DESCRIPTION                      ORBITS
---------        -----      ------------                     ------
QTSISAIF         Y-LO    SSPP Baseplate by SISA I/F     39845-912
QTACRIMIF        Y-LO    SSPP Temp at ACRIM I/F         39845-96


The following ALERT occurrences were detected:

MNEMONIC                    DESCRIPTION                      ORBITS
---------                   ------------                    ------
ACTEMPHMREDL            ACRIM RED LOW                      39897-8
ACTEMANA1RDL            ACRIM RED LOW                      39897-8, 900     
ACTEMANA2RDL            ACRIM RED LOW                      39897-8
SOPUPERSTATA            SOLSTICE DETECTORS OFF             39900     
SOPUPERSTATA            MODE SELECTED= "TWO" RED           39903     



_______________________________________________________________

                              APPENDIX C
                 CLOCK & SOLAR ARRAY RATE CORRECTIONS
                       Week ending 01 January 1999

                      CLOCK DRIFT RATE ADJUSTMENTS

     ORBIT              TIME                 CLOCK RATE CHANGE
     -----              ----                 -----------------
     39872     362/07:47 (28 Dec 98)     from 00.0 to 20.6 msec/day
     39900     364/04:23 (30 Dec 98)     from 20.6 to 00.0 msec/day


_______________________________________________________________


                             APPENDIX D
                    UARS BATTERY PERFORMANCE DATA
                       Week ending 01 January 1999


     25 Dec 1998 - GMT Day 359 Beta = 32.2 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   +61.6/+39.2  -2.73/-3.99   +0.0/ +0.0    16.8    0.000     0.0
2   +11.2/-67.2  +6.11/+5.15  +30.4/-15.2    25.3    1.028    21.8
3   +134.4/11.2  +5.15/+3.87  +30.0/-16.4    25.1    1.024    21.7


     01 Jan 1999 - GMT Day 001 Beta = 29.9 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/+33.6  -2.73/-3.99   +0.0/ +0.0    16.8    0.000    0.0
2   +33.6/-22.4  +6.44/+5.15  +31.2/-15.2    25.1    1.026   21.8
3   +44.8/-5.6   +5.15/+3.87  +30.4/-16.0    25.1    1.025   21.6


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





                               APPENDIX E
                         UARS ANOMALY REPORTS
                      Week ending 01 January 1999


                     NEW ANOMALY REPORTS GENERATED
  AR NO.   SUBSYS   ORBIT      TIME       TTR      PROBLEM/DATA LOSS
  ------   ------   -----      ----       ---      -----------------
98-124     FOT      39878     362/1757   20485     No ODM/GCMR capability



                 ANOMALY CLOSURE INFORMATION RECEIVED
  AR NO.   SUBSYS   ORBIT      TIME       TTR      PROBLEM/DATA LOSS
  ------   ------   -----      ----       ---      -----------------
                    None this report period


                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
  ------   ------   -----      ----       ---      -----------------
98-117     FOT       Dec 98    353/07:02  14170   Generic Late Acq
98-123     FOT       39788     356/17:45          AP/ODN PROBLEM
98-124     FOT       39878     362/18:00  20485   N0 ODM/GCMR 




_______________________________________________________________
                               APPENDIX F
                   UARS INSTRUMENT OPERATIONS SUMMARY
                      Week ending 01 January 1999


              INSTRUMENT SUMMARY FOR MONTH OF DECEMBER 1998 (hours)


                                     UNPLANNED   UNSCHEDULED
              ON    Day-    OFF         OFF         OFF     
                    Only           (Insufficient  (Other
Instrument (Actual) Ops (Scheduled)   Power)      Problem)       COMMENTS
----------  ------  --- ----------- -----------  ----------- --------------

ACRIM        599           145         0            0

HALOE        575           169         0            0

HRDI         216     528   0           0            0

MLS          141           603         0            0

PEM (axis)   142     0     602         0            0

PEM (zeps)   4       715   25          0            0

PEM (heps)   4       0     740         0            0          See Note 1

SOLSTICE     600     144   0           0            0

SUSIM        597           147         0            0

WINDII       235           509         0            0


Note 1.     PEM High Energetic Particle System (HEPS) was OFF while 
developing and testing automated turn-on procedure. The automated procedure 
will operate while the spacecraft is in daylight and has power available 
from the solar array.  (When spacecraft is in darkness, operation of 
instruments and
spacecraft systems rely on power from batteries.  Only two of the three 
spacecraft batteries are currently operational.  Battery power is not 
sufficient to operate all instruments simultaneously when spacecraft is in 
darkness.).

Cold side of spacecraft was facing northward:   12.5 days
Cold side of spacecraft was facing southward:   18.5 days


	 	SEVNTFW99/01