UARS Weekly Status Report

16 June 2000




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                UARS WEEKLY STATUS REPORT - 16 JUN 2000

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

Nothing received.

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

SUSIM continues to gather a near normal set of daily solar scans
scheduled for periods of predicted telemetry.

Despite the unexpected spacecraft power off on June 7, the monthly
lamp calibration was completed successfully beforehand.

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

Nothing received.

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

     The PEM spectrometer daylight operation was interrupted beginning June 5
due to the power negative condition which existed with the UARS batteries.
PEM Daylight operations resumed on June 14.  The delay from activation on
June 9 was due to battery low conditions still occurring.  The PEM spectrometer
operation in daylight is active under PMON control* when PMON is enabled.

     At the present time, PEM energy deposition is not being generated.  
Recent data configuration changes have affected PEM software causing multiple 
failures.  These failures are being reviewed by the PEM team.  In order to 
correct for new telemetry requirements, PEM will need to update processing 
code with a patch delivery.  The delivery patch will not include changes which
would allow the PEM software to execute on a DEC Alpha machine.

    Updated HEPS calibration parameters have been finalized and are ready for 
delivery.  Updated MEPS quality calibration files have been finalized and are 
ready for delivery.  Level 3 software errors, discovered by Dr. Dean Pesnell, 
have been fixed; his suggestions have been incorporated with in the PEM 
production code.  Both updated HEPS and MEPS calibration data, along with the 
Level 3 code changes, will influence the in-situ energy deposition predictions,
so new versions of PEM energy deposition Level 3 files will be generated.

*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.

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

Nothing received.

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

Nothing received.

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

WINDII is scheduled to operate June 18 - 26. It will be configured
for the observation of polar mesospheric clouds. 

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

From an action item of the UARS Mission Status Review meeting (on
June 8) the MPG has queried instrument teams about their use of
UARS Quick Look data.  Responses have been received from three
instruments so far, and these three do not use Quick Look data.

Processing of instrument Daily Activity Plans continues with no
problems. We are continuing to assist the Project Scientist in
scheduling of instrument operations.  

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

STATUS:                          
   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.
    -  All requested reprocessing is complete as of this reporting period.   

CDHF REHOST:
   -  Successful processing on Rehost System:
       Attitude Extraction, Observatory Log, Sensor Extraction, HALOE, HRDI,
       MLS, SUSIM, Solstice, and WINDII.
   -   Waiting validation results from the HRDI group on successful
       production testing done on the Rehost System.
   -   System tests being done.                    
                  
***********
FOT
***********

                               REPORTING PERIOD

This report covers 03 June 2000 (Orbit 47703, GMT Day 155) through 09 June 2000 
(Orbit 47807, GMT Day 161).

                             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
       PEM            157/1706    47743         Off
       HRDI           157/2138    47745         Standby
       SOLSTICE       159/2000    47774         On
       ACRIM          160/0105    47778         On
       SUSIM          160/1346    47786         On
       HRDI           161/0007    47792         Restart
       HRDI           161/0331    47794         Day Only
       HALOE          161/1306    47800         On

A Forward-to-Reverse Yaw Around maneuver (number 89) was successfully executed 
in Orbit 47742 beginning 157/16:01:29 and completing at 157/16:38:39 on 05 June 
2000.  The SSPP Instruments (ACRIM, SOLSTICE, SUSIM) were enabled as well as 
HRDI and PEM in day only operations.  Due to the SA position at 269 degrees, 
the effective night length of the spacecraft after the maneuver was 
approximately 55 minutes.  Post maneuver analysis of data indicate that during 
the Yaw Around, the end-of-night load bus voltage was 23.2 volts and the 
average depths of discharge (DODs) on Batteries 2 and 3 were approximately 24.5 
and 24.6 percent respectively.  The next (reverse-to-forward) YAW is scheduled 
for 04 July 2000 (DOY 186).

The beta angle ranged between the angles of 11.7 degrees to 13.7 degrees for 
this report period.  The beta angle is now increasing toward a maximum angle of 
34.0 degrees on 20 June 2000 (DOY 172).

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 23.2 V end-of-night (EON) load bus voltage.  Battery 
temperatures are stable with a temperature delta between Battery 2 and Battery 
3 of 0.6 to 1.0 degrees C.  Additional battery performance data for each 
battery on  02 June 2000 and 09 June 2000 are provided in Appendix D.

The clock error ranged from -13.8 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 = 13
% ALERTS        = 02 

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

% FOT           = 07
% SUSIM         = 04
% HRDI          = 04
% HALOE         = 02
% PEM           = 01
% SOLSTICE      = 01
% ACRIM         = 01

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

% FOT           = 03

Five (5) Anomaly Reports remained OPEN at the end of this report period (see 
Appendix E).

TRANSPONDER FREQUENCIES:
- Transponder A:  00/145  -  2287.497008
- Transponder B:  00/152  -  2287.498920


                          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 00/160 show the observatory data loss to be 296 hours, 20 
minutes, 7.713 seconds (an increase of 40 minutes 13.672 seconds since the last 
report period).  This is a 0.40 percent data loss which equals a 99.60 percent 
data capture for the mission.

The increase of 40 minutes 13.672 seconds occurred over two (2) days:

- 0 minutes 08.576 seconds on Day 156 due to a data hit.
- 40 minutes 05.096 seconds on Day 159 due to a late AOS and an early off to 
conserve power.


                         OTHER SIGNIFICANT EVENTS

                         UARS SATELLITE OPERATIONS

The OBC Telemetry Monitors (TMONs) 1 and 2 tripped during this report period.  
These TMONs shed load when the EON Voltage on Batteries one and two get too 
low.  An investigation has begun to find the cause of this anomaly.  
Preliminary findings suggest an insufficient power margin caused the TMONs to 
trip, not a battery degradation problem.  All instruments have been returned to 
their scheduled operations with the exception of PEM, which should resume its 
operations soon.

The FOT continues to test the new TMONs on the simulator.  Once the TMONs have 
been thoroughly tested, they will be presented for review and approval before 
uplink.

The FOT has begun writing the online procedure for safehold should it happen 
before the new TMONs are in place or during and OBC halt.  This procedure will 
be tested on the simulator and put online for immediate execution should an 
anomalous condition take place.


                                  MEETINGS

The FOT attended the UARS Monthly Meeting on 07 June 2000.


                         FUTURE SIGNIFICANT EVENTS

The next UARS Yaw slew is scheduled for July 04, 2000 (DOY 186).  This maneuver 
will be a Reverse to Forward Flight maneuver (Southern 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 09 June 2000
 
  ORBIT   AOS        NO.      SUBSYS      REASON
  -----   ---        ---      ------      -------
  47708   155/1000   00-249   OBC         Clk Adj fr 20.6 to 0.00 msec/day
  47713   155/1832   00-250   SUSIM       SUNACTIV
  47714   155/1939   00-251   OBC         Clk Adj fr 0.00 to -20.6 msec/day
  47718   156/0223   00-252   SUSIM       Command request
  47723   156/1002   00-253   SUSIM       Cmds to replace daily microload
  47734   157/0305   00-254   OBC         Clk Adj fr -20.6 to 0.00 msec/day
  47741   157/1506   00-255   OBC         YAW AROUND
  47743   157/1706   00-256   PEM         Power OFF DUE TO S/C LOW PWR
  47745   157/2138   00-257   HRDI        HRDI TO STBY
  47773   159/1819   00-257   HRDI        Power ON to STBY only
  47774   159/2000   00-258   SOLSTICE    Power ON
  47775   159/2149   00-259   NBTR        PLAYBACK
  47778   160/0105   00-260   ACRIM       Power ON
  47786   160/1346   00-261   SUSIM       Power ON
  47792   161/0007   00-257   HRDI        RESTART 
  47794   161/0331   00-262   HRDI        HRDI: DAY-OPS ONLY
  47796   161/0625   00-263   NBTR        NOOPS D-161
  47800   161/1306   00-264   HALOE       Power ON: P-1
  47804   161/1904   00-265   NBTR        NOOPS D-162
  47805   161/2146   00-266   HALOE       Power ON: P-2



                                 APPENDIX B
                     OUT-OF-LIMITS & ALERTS OCCURRENCES
                          Week ending 09 June 2000

The following Out-Of-Limits occurrences were detected:

     MNEMONIC        STATE      DESCRIPTION              ORBITS
     ---------       -----      ------------             ------
     HRPSEQBIMON     Y-HI       PSE QB CURRENT MON       47724-30
     HRPTSPBIMON     R-LO       PTS PB CURRENT MON       47724
     HRPSEQBIMON     Y-HI       PSE QB CURRENT MON       47740-3
     OBSVLBEON       Y-LO       EON LOAD BUS VOLTAGE     47741-4
     OBSBATVEON2     Y-LO       EON Bat 2 voltage        47741-4
     OBSBATVEON3     Y-LO       EON Bat 3 voltage        47741-4
     PWLBV           Y-LO       LOAD BUS VOLTAGE         47742-3
     HRPTSPBIMON     R-HI       HRDI PB CURRENT          47746
     HRPTSPBIMON     Y-HI       HRDI PB CURRENT          47746
     HRPSEQBIMON     Y-HI       PSE QB CURRENT           47754-9
     PWBAT3V         Y-LO       BATT 3 VOLTAGE           47742-3
     PWBAT2V         Y-LO       BATT 3 VOLTAGE           47742-3
     CDUNRG28        Y-LO       28 VOLT UNREG BUS        47742-3

The following ALERT occurrences were detected:

     MNEMONIC                   DESCRIPTION              ORBITS
     --------- -                -----------              ------
     SOPUPERSTATA               Solstice voltage low     47766
     ACINVMCNREDL               ACRIM volt is red low    47766



                                 APPENDIX C
                    CLOCK & SOLAR ARRAY RATE CORRECTIONS
                          Week ending 09 June 2000

                        CLOCK DRIFT RATE ADJUSTMENTS

    ORBIT      TIME                       CLOCK RATE CHANGE
    -----      ----                       -----------------
    47708      155/10:02 (03 June 00)     from 20.6 to 0.00 msec/day
    47714      155/19:47 (03 June 00)     from 0.00 to -20.6 msec/day
    47734      157/03:08 (05 June 00)     from -20.6 to 0.00 msec/day

_______________________________________________________________________________

                                 APPENDIX D
                        UARS BATTERY PERFORMANCE DATA
                          Week ending 09 June 2000


 02 June 2000 - GMT Day 154 Beta = 11.7 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    +22.4/+0.0     -3.05/-4.62   +0.0/+0.0     15.7    0.000    0.0
2    +39.2/-22.4    +6.44/+3.87   +30.4/-14.4   24.5    1.040    20.4
3    +22.4/-67.2    +5.15/+2.92   +29.6/-14.4   24.3    1.038    19.7


 09 June 2000 - GMT Day 161 Beta = 13.7 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    +33.6/+11.2    -3.05/-4.62   +0.0/+0.0     15.7    0.000    0.0
2    +44.8/-22.4    +5.79/+4.51   +29.6/-16.0   24.3    1.030    20.6
3    +22.4/-67.2    +4.83/+3.23   +28.8/-15.6   24.2    1.027    20.2


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


                                 APPENDIX E
                            UARS ANOMALY REPORTS
                           Week ending 09 June 2000

                         NEW ANOMALY REPORTS GENERATED
     AR NO.    SUBSYS    ORBIT      TIME      TTR    PROBLEM/DATA LOSS
     ------    ------    -----      ----      ---    -----------------
     00-024    FOT       47742      157/1635  N/A    TMON 1 trip
     00-025    FOT       47766      159/0657  N/A    TMONS 1 & 2 tripped
     00-026    FOT       47770      159/1300  14170  Generic Late Acq.

                     ANOMALY CLOSURE INFORMATION RECEIVED
     AR NO.    SUBSYS    ORBIT      TIME      TTR    PROBLEM/DATA LOSS
     ------    ------    -----      ----      ---    -----------------
     00-007    FOT       see list   May 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
    ------     ------    -----     ----      ---     -----------------
   99-064      FOT       44135     10/8-9/99  N/A     HRDI Cal Lamp Errors
   99-071      FOT       44398     299/1212   21512   TPF Not Receiv 512
   00-024      FOT       47742     157/1635   N/A     TMON 1 trip
   00-025      FOT       47766     159/0657   N/A     TMONS 1 & 2 tripped
   00-026      FOT       see list  June 00    14170   Generic Late Acq.

	 	SEVNTFW00/23