UARS Weekly Status Report

15 December 2000




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                UARS WEEKLY STATUS REPORT - 15 DEC 2000

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

This week was a fairly typical one for SOLSTICE in which we collected solar
data on all available orbital tracking periods and stellar calibration
observations whenever possible. 

However, on Tuesday (00347) the FOT failed to load our microprocessor loads
per the DAP and the instrument observation list became out of sync with
where the SSPP was pointing. Consequently, at 15:04z on Wednesday (00348)
the instrument was configured for what it thought was a stellar target
when, in fact, the sun was being tracked. This lasted for 8 minutes causing
a sharp degradation in our detectors. The FOT noted some telemetry out of
limits and took the proper, corrective action to safe the instrument
preventing further damage. This has happened in the past but not for a
number of years and the instrument typically makes a slight recovery over
the following few days. The magnitude of this particular incident is under
investigation as we see how the instrument responds over the next week.

Other than this problem, We continue to gather enough data to meet all the
SOLSTICE science objectives during this period of reduced tape recorder
operations.

We are satisfied with the OA_SSPP_ATT patch in regards to how it handles
the data gaps as it has allowed us to process (under RSS) 400 days worth of
data. After analysis of this data we are making some modifications to our
production software.

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

Nothing received.

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

Nothing received.

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

Nothing received.

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

HALOE continues successful operations after powering on December 7, 2000.
All engineering parameters are within nominal operating region and the
science data results are excellent.

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

Nothing received.

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

Nothing received.

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

Nothing received.

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

Daily processing of instrument Daily Activity Plans continues
with no problems.  Instrument operations schedule is now 
complete to 9 February 2001.

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

UARS CDHF continues to notify PI Software Representatives regarding Data Gaps
that occur in the LEVEL0 data due to the UARS Spacecraft Anomaly.

DAAC DATA:
   -  Data created in the month of October, 2000 has been previewed for
      HALOE, MLS V5, NMC, PEM, and UKMO in preparation for sending to the DAAC.
                        
UARS CDHF REHOST:
   -  Need positive response from all PI End Users prior to Rehost transition.
   -  PI validation of output products and concerns are being addressed.
   -  Testing of PEM V3.32 (JOBS 1 and 2) are in progress.
   -  System performance being confirmed.
                  
***********
FOT
***********


                         REPORTING PERIOD

This report covers 02 December 2000 (Orbit 50431, GMT Day 337) through 08 
December 2000 (Orbit 50535, GMT Day 343).

                      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
 ACRIM        338/0034     50446     Power On
 SUSIM        338/0256     50448     Power On
 PEM          339/1317     50469     Day Only
 HALOE        341/1320     50499     Power On


A Reverse-to-Forward Yaw Around maneuver (number 94) was successfully executed 
in Orbit 50440 beginning 337/14:14:46 and completing at 337/14:51:56 on 02 
December 2000.  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 minutes.  Post maneuver analysis of 
data indicate that during the Yaw Around, the end-of-night load bus voltage was 
24.5 volts and the average depths of discharge (DODs) on Batteries 2 and 3 were 
approximately 22.5 and 23.0 percent respectively.  The next (forward-to-
reverse) YAW is scheduled for 31 December 2000 (DOY 366).

The beta angle ranged between the angles of 1.5 degrees to 19.8 degrees for 
this report period.  The beta angle is now increasing towards a maximum angle 
of 34 degrees on 17 December 2000 (DOY 352).

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 and 1.3 degrees C respectively.  Additional battery performance data 
for each battery on 1 December 2000 and 8 December 2000 are provided in 
Appendix D.

The clock error ranged from Ð10.3 to 12.0 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            =  22
¥     PEM            =  01
¥     HALOE          =  02
¥     ACRIM          =  01
¥     SUSIM          =  02

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

¥     FOT            =  00

Two (2) Anomaly Report remained OPEN at the end of this report period (see 
Appendix E).

TRANSPONDER FREQUENCIES:
· Transponder A:  00/315  -  2287.496493
· Transponder B:  00/314  - 2287.498584
 
                       GROUND SYSTEM OPERATION
 
 One (1) operational support problem 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 00/342 show the observatory data loss to be 300 hours, 01 
minutes, 24.888 seconds. This shows an overall decrease of 37.280 seconds since 
the last report period.  This is a 0.39 percent data loss, which equals a 99.61 
percent data capture for the mission.
 
 The decrease of 37.280 seconds occurred over one (1) day:
 
· 37.280 seconds on Day 339 due to a data hit.

                     OTHER SIGNIFICANT EVENTS

                    UARS SATELLITE OPERATIONS

UARS attitude control continues to be the focal point of the FOT's activities 
this week.  The TAM was placed in update mode on 06 December 2000 for one orbit 
(341/1837-2019 GMT).  The results of this test showed the TAM performing as 
expected with very little increase in the FSS residuals.  As a result the TAM 
was put into update from 343/1300-2000 GMT on 08 December 2000.  This test 
yielded much different results.  It showed as much as 1.5 degrees of error on 
the roll and yaw axes at certain points in the orbit.  It was then determined 
that this attitude error had to be eliminated for the TAM to work properly on a 
converged filter.  This will be discussed in detail next week and be 
implemented on 12 December 2000.


                           MEETINGS

The FOT attended a TAM Attitude Meeting on 05 December 2000.

The FOT attended a TAM Attitude Meeting on 06 December 2000.

The FOT attended a monthly UARS Status Meeting on 06 December 2000.


                    FUTURE SIGNIFICANT EVENTS


The next UARS Yaw slew is scheduled for December 31, 2000 (DOY 366).  This 
maneuver will be a Forward to Reverse Flight maneuver (Northern Hemisphere 
viewing).


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 08 December 2000

ORBIT     AOS        NO.      SUBSYS     REASON
-----     ---        ---      ------     ------
50439     337/1330   00-686   ACS        GYRO BIAS UPDATE FOR FWD FLIGHT
50439     337/1330   00-687   ACS        FSS TO MONITOR MODE
50441     337/1603   00-688   ACS        FSS TO UPDATE MODE
50446     338/0034   00-689   ACRIM      Power ON
50448     338/0256   00-690   SUSIM      Power ON - Start
50454     338/1418   00-690   SUSIM      Power ON - Complete
50456     338/1606   00-691   OBC        Clk Adj 0.00 to -20.6 msec/day
50469     339/1317   00-692   PEM        Power ON ZEPS,HEPS day only
50472     339/1834   00-693   OBC        Clk Adj -20.6 to 0.00 msec/day
50487     340/1836   00-694   ATC        NOOPS D-341
50493     341/0414   00-694   NBTR       NOOPS D-341
50499     341/1320   00-695   HALOE      Power ON
50501     341/1654   00-697   ACS        MAG MODEL TIME COORRECTION
50502     341/1758   00-696   NBTR       NOOPS D-341
50502     341/1837   00-698   HALOE      Power ON, COMPLETE
50502     341/1837   00-699   ACS        TAM TO UPDATE MODE
50503     341/2019   00-699   ACS        TAM TO MONITOR MODE
50510     342/0636   00-696   NBTR       NOOPS D-342
50517     342/1759   00-700   NBTR       NOOPS D-343
50525     343/0639   00-700   NBTR       NOOPS D-343
50528     343/1245   00-701   ACS        TAM TO UPDATE MODE
50531     343/1652   00-700   NBTR       NBTR NOOPS D-343
50532     343/1800   00-702   ACS        FWD FLIGHT GYRO BIAS
50532     343/1800   00-703   ACS        DUMP TBL 35/36
50532     343/1840   00-704   ACS        RESIDUAL LIMITS
50533     343/1940   00-706   ACS        FSS
50533     343/1940   00-701   ACS        TAM TO MONITOR MODE
50533     343/1940   00-705   NBTR       NOOPS D-344
__________________________________________________________________________

                           APPENDIX B
               OUT-OF-LIMITS & ALERTS OCCURRENCES
                  Week ending 08 December 2000

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 08 December 2000

                  CLOCK DRIFT RATE ADJUSTMENTS

ORBIT     TIME            CLOCK RATE CHANGE
-----     -----           -----------------
50456     338/1616        Clk Adj from 0.00 to -20.6 msec/day
50472     339/1843        Clk Adj from -20.6 to 0.00 msec/day

__________________________________________________________________________

                           APPENDIX D
                UARS BATTERY PERFORMANCE DATA
                 Week ending 08 December 2000


     01 Dec 2000 - GMT Day 336 Beta = 03.7 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  -3.68/-4.94  +0.0/+0.0    14.2    0.000    0.0
2   +5.6/-100.8    +5.15/+4.51  +29.6/-13.2  25.1    1.020    21.0
3   +44.8/-11.2    +3.87/+2.92  +28.8/-13.6  25.1    1.020    21.0


     08 Dec 2000 - GMT Day 343 Beta = 19.8 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  -3.05/-4.62   +0.0/+0.0    14.2     0.000    0.0
2    +0.0/-112.0    +5.47/+4.51   +30.8/-13.6  25.1     1.040    21.1
3    +22.4/-50.4    +4.51/+3.23   +30.0/-14.8  25.1     1.020    20.9


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


                      APPENDIX E
                       UARS ANOMALY REPORTS
                    Week ending 08 December 2000

                    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
------     ------     -----     ----     ---     -----------------
00-047     FOT        see list  Nov 00   14170   Generic Late Acq.


              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
------     ------     -----     ----       ---     -----------------
00-053     FOT        50168     319/1113   23157    Late Acquisition
00-054     FOT        50280     326/2147   23187    RESET PTP /2:39 32K



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