UARS Weekly Status Report

5 June 1998





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                UARS WEEKLY STATUS REPORT - 05 June 1998

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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
***********

SUSIM has successfully gathered its normal solar, offset, and
occultation scan data without apparent problems.

We expect to place a new version of the SUSIM production software into
CDHF Engineering mode during the coming week.

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

     PEM/AXIS was active from May 22 through May 23.  It generated energy
deposition from inverted X-ray   spectra for each of its 16 look directions.  

     GSFC has proposed an OBC operation plan for the activation of PEM boom 
instruments during the daylight portions of every orbit.  This OBC operation 
plan is accepted by PEM.  PEM has proposed a series of test procedures for 
activation and is waiting response from GSFC.  PEM is also waiting for GSFC
scheduling and implementation of the OBC plan and its operation test procedures.

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

Nothing received.

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

     At the end of the last operating period for MLS, the MLS instrument
experienced a minor recurrence of the scan slips last observed several years
ago.  These occurred during the last 3 periods of lowest bus voltage just prior
to normal instrument turn off.

     Close examination of the Level 0 data indicates that

  1. all scan slips took place during retrace, when the scan motor is known to
     have lowest torque,
  2. no additional wear is evident in the scan mechanism compared to data taken
     several years ago, and
  3. recovery from the anomalies was handled promptly and correctly by the
     on-board software.

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

Nothing received.

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

Gordon Shepherd is currently in Boulder, at HAO/NCAR, working with
Ray Roble on WINDII comparisons with the TIME-GCM. 

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

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

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

The CDHF has received a total of 390 CD-ROM requests as of 04-June-1998.
There were no new orders received.

The problem encountered by the UK Meteorological Office at an intermediate
point has been corrected.  The CDHF is currently up to date receiving the
UKMO data.

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.           
                  25 days PEM (3.32) PROD        (1379R-1313C=66L)
                  61 days HAL (4.80) PROD (L1)   (1868R-311C-2F=1555L)
                  31 days HAL (4.80) PROD (L3)   (1868R-75C=1793L)
                 611 days SOL (4.61) PROD (L1)   (2404R-1154C=1250L)
                  93 days SOL (4.61) PROD (L3)   (2304R-169C=2135L)
                   1 day  SUS (6.3)  PROD        (1R-1C=0L) 
                   1 day  HRDI(4.4)  PROD        (1R-1C=0L)
        
CDHF pending software upgrades: IDL 5.1, OpenIngres 
                  
***********
FOT
***********

REPORTING PERIOD

This report covers 23 May 1998 (Orbit 36588, GMT Day 143) through 29 May 
1998 (Orbit 36692, GMT Day 149).


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       143/0754     36593     Axis Off*
           WINDII     143/0754     36593     Off*
            HRDI      143/2333     36603     Low Pwr Mode
           WINDII     144/2243     36617     On
           WINDII     145/1316     36626     Off

          * TMON 01 activation

The beta angle reached a maximum angle of 78.0 degrees on 26 May 1998 (DOY 
146 and is now decreasing toward a minimum angle of 0.0 degrees on 15 June 
1998 (DOY 166).

On Board Computer (OBC) Telemetry Monitor (TMON) 01 tripped in Orbit 36593 
on 23 May 1998 (143/0745) due to low voltage (23.36 volts).  This resulted 
in Relative Time Sequence (RTS) 00 activation which powered OFF an energy 
balance deficit and TMON 00 trip which commanded off WINDII, HRDI, and PEM.  
Power balance was restored after TMON 01 tripped.  HRDI returned to low 
power in orbit 36603 (143/2333).  WINDII was turned back on in Orbit 36617 
(144/2243), but had to be turned back off in Orbit 36626 (145/1316) due to 
power balance deficit.  The SSPP instruments and MLS remained ON throughout 
the high solar beta range above 73 degrees.  The spacecraft had increased 
thermostatic heater activity at the high solar beta angle, and coupled with 
near minimum solar array output, was unable to support the scheduled 
instrument loads.

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 23.6 V end-of-night (EON) load bus voltage. 
Battery temperatures are increasing (due to high beta angle and low depth-
of-discharge) with a temperature delta between Battery 2 and Battery 3 of 
1.0 degrees C.  Additional battery performance data for each battery on 23 
May 1998 and 30 May 1998 are provided in Appendix D.

The clock error ranged from -10.6 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         =     none
%     OUT-OF-LIMITS  =     012

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

%     FOT     04
%     HRDI    02
%     PEM     01
%     WINDII  02

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

%     FOT     03

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

TRANSPONDER FREQUENCIES:
     Transponder A:  98/118  -  2287.497007
     Transponder B:  98/120  -  2287.498907



GROUND SYSTEM OPERATION

Two (2) operational support problem(s) 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 98/148 show the observatory data loss to be 
20 hours, 43 minutes, 29.652 seconds (no change since last report period).  
This is a 0.0354 percent data loss which equals a 99.9646 percent data 
capture for the mission.

The FOT made a few more modifications to the OBCSTF resident POCC database 
this week. These changes were necessary to accommodate the proposed HRDI 
"day-only" operations scenario.  

The FOT made a few additional modifications to the OBCSTF resident POCC 
database this week.  These changes were necessary to accommodate the 
proposed HRDI "day-only" operations scenario.  Due to unavailability of the 
MSOCC software coordinator this week, testing of the latest version of 
database 67 will most likely be delayed until next week.

Testing the command side of the I/P Net remains on hold.  Testing will 
begin when MSOCC provides a command loop interface from the POCC through 
the I/P Net to the UARS Simulator.


OTHER SIGNIFICANT EVENTS

Continued testing of the upgrade to the OBC Power Monitor (PMON) flight 
software.  PMON software modifications and testing continued this week.  
Multiple simulations on the new AP software including both the new database 
version 67 and the old version 65.  Highlights of the testing involved 
integration and validation of HRDI commands into the new power-orbit action 
plan.  Minor changes to other instrument RTSUs were required.

Work continues on the UARS orbit adjust planning scheduled for 05 August 
1998.  Additional options for an Orbit Adjust are being planned in the 
event that the B/D thrusters can not be safely used.

UARS continues to assiste TOMS in reviewing the TOMS/EP Transmitter A 
failure data.

FOT continues to support CNMOS in their efforts to make necessary software 
changes (MSOCC, CMS, DCF, etc.) to support the year 2000 rollover. The FOT 
requested a set of "test" planning aids from FDF to facilitate Year 2000 
ground system testing.  FDF informed the FOT that they are currently in the 
process of generating planning aids that span the Year 2000 crossover.

Monitoring of the magnetic field model performance continues.

FOT continues to improve a Power Profile for UARS based on the current 
status of the Modular Power System.

FOT continues to support the new UARS ground system re-engineering effort.


MEETINGS

No UARS Battery telecon was held this week.  The next telecon has not been 
scheduled.


FUTURE SIGNIFICANT EVENTS

The next UARS Yaw Around Maneuver is currently scheduled for 15 June 1998.

The UARS orbit altitude is dropping slowly and a drag makeup orbit adjust 
is targeted for 05 August 1998.


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 A
                       REAL-TIME COMMAND SHEETS
                      Week ending 29 May 1998

ORBIT       AOS        NO.    SUBSYS      REASON
-----       ---       ---     ------      -------  
36594    143/0937    98-176   PEM      Inhibit Mission Unique Bit
36600    143/1913    98-177   HRDI     Power ON to Low Power
36603    143/2333    98-178   HRDI     Pulse Bus Off
36617    144/2243    98-179   OBC      Clk Adj from 41.2 to 20.6 msec/day 
36617    144/2243    98-180   WINDII   Power ON
36625    145/1122    98-181   PSU      Comp Htr 18 A/B OFF
36626    145/1316    98-182   WINDII   WINDII TURN OFF
36638    146/0805    98-183   OBC      Clk Adj from 20.6 to 41.2 msec/day
36689    149/1754    98-184   OBC      Clk Adj fr 41.6 to 20.6 msec/day




_______________________________________________________________

                               APPENDIX B
                  OUT-OF-LIMITS & ALERTS OCCURRENCES
                      Week ending 29 May 1998

MNEMONIC        STATE        DESCRIPTION                       ORBITS
---------       -----       ------------                      ------
WIPBVOLTAGE     Y-LO     WINDII Pulse Bus Voltage     36592,36625
HRPSEQBIMON     Y-HI     HRDI Q/B Current Monitor     36592,36623-25,28
CDUNRG28        Y-LO     Unregulated +28 Voltage      36592-3,36624,25
PWLBV           Y-LO     Load Bus Voltage             36593
WIQBVOLTAGE     Y-LO     WINDII Quiet Bus Voltage     36624
PWBAT3V         Y-LO     Battery 3 Voltage            36593
PWBAT2V         Y-LO     Battery 2 Voltage            36593
OBSVLBEON       Y-LO     Last EON Load Bus Voltage    36593-4,36626
OBSBATVEON2     Y-LO     Battery 2 EON Voltage        36593-4
OBSBATVEON3     Y-LO     Battery 3 EON Voltage        36593-4
HRIFESURVTMP    Y-HI     IFE Survival Heater Temp     36594
HRRADTEMP       Y-HI     IFE Radiator Temp            36594          


The following ALERT occurrences were detected:

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



                               APPENDIX C
                 CLOCK & SOLAR ARRAY RATE CORRECTIONS
                      Week ending 29 May 1998

                      CLOCK DRIFT RATE ADJUSTMENTS

     ORBIT              TIME                 CLOCK RATE CHANGE
     -----              ----                 -----------------
     36617     144/22:48 (24 May 98)     from 00.0 to 20.6 msec/day
     36638     146/20:44 (26 May 98)     from 20.0 to 41.2 msec/day
     36689     149/17:35 (29 May 98)     from 41.2 to 20.0 msec/day


_______________________________________________________________

                               APPENDIX D
                    UARS BATTERY PERFORMANCE DATA
                      Week ending 29 May 1998

     23 May 1998 - GMT Day 143 Beta = 73.0 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  -2.94/-4.64    +0.0/ +0.0   18.2     0.000   0.0
2    +42.0/  +0.0  +3.87/+2.10   +17.1/-16.1   23.5     1.043  21.8
3    +67.6/  -5.6  +3.06/+1.34   +16.8/-16.2   23.4     1.045  21.3

     29 May 1998 - GMT Day 149 Beta = 71.0 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/-4.31    +0.0/ +0.0   18.4     0.000   0.0
2    +44.8/ -11.2  +3.42/+2.05   +18.0/-15.2   26.9     1.039  18.3
3    +67.5/  -5.5  +2.50/+1.34   +17.3/-14.4   26.7     1.038  18.1


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



                               APPENDIX E
                         UARS ANOMALY REPORTS
                      Week ending 29 May 1998


                     NEW ANOMALY REPORTS GENERATED
  AR NO.  SUBSYS   ORBIT      TIME      TTR      PROBLEM/DATA LOSS
  ------  ------   -----      ----      ---      -----------------
98-025   FOT     36592     143/0616   19919   Incomplete Config. TDRS
98-021   FOT     36603     144/0107   14170   Generic Late Acquisition
98-026   FOT     36680     149/0315           TAC #4 Crashed


                  ANOMALY CLOSURE INFORMATION RECEIVED
  AR NO.  SUBSYS   ORBIT      TIME      TTR      PROBLEM/DATA LOSS
  ------  ------   -----      ----      ---      -----------------
98-025   FOT     36592     143:06:16  19919    WHITE SANDS CONF.


                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
  ------  ------   -----     ----       ---      -----------------
98-021   Generic Late Acq for May 1998 (Open until 31 May 1998).