UARS Weekly Status Report

19 NOVEMBER 1999




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                UARS WEEKLY STATUS REPORT - 19 NOV 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. We remained on and collecting normal data during the 
Leonids event this week.

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

SUSIM successfully gathered its normal solar data this past week without
apparent problems.  Occultation scans still remain suspended.  These will
resume if telemetry continues to be stable.

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

Nothing received.

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

Nothing received.

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

Nothing received.

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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
***********

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. 

During this week the MPG has been involved with the evaluation
of the potential impact on instrument operations in case both 
tape recorders become unuseable.  Without tape recorders, science 
data can continue to be collected during real time contacts, but 
the expanded time of transponder operations would draw some power 
which would otherwise be available to the instruments.  

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

The CDHF has notified PI Software Representatives that no Data Gaps were
among the ingested times for UARS DAYS 2983 - 2986.  Production processing
has resumed with normal processing results. 
                             
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.
        17 days CLA (7.0)   PROD (L1-L3)         (476R-391C-19F=66L)
        22 days GPI (4.05)  PROD (CLAES L3B)     (334R-307C-2F=25L)
        21 days WIN (5.11A) PROD (LOG)           (21R-21C=0L)
         3 days WIN (5.11A) PROD (L1-L3)         (21R-3C-2F=16L)
Promoted WINDII V5.11A software to Production Mode.
  
DAAC DATA:
   -  All of the SUSIM Level 3BS (Output 20) UARS DAYS 31-2523 that SUSIM 
      requested to be sent to the DAAC has been loaded into the DAAC Transfer
      Tables.  SUSIM and DAAC have been notifed.

CDHF REHOST:
Testing SUSIM V7.1 on the Rehost System.
Preparing to test SOLSTICE V4.62 on the Rehost System.

***********
FOT
***********

REPORTING PERIOD

This report covers 6 November, 1999 (Orbit 44556, GMT Day 310) through 12 
November 1999 (Orbit 44660, GMT Day 316).


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
                 HALOE      314/1352     44624     Off
                 PEM        314/1954     44627     AXIS On
                 PEM        315/2322     44645     AXIS-2 Off

The beta angle ranged between the angles of 30.3 degrees to 60.8 degrees for 
this report period.  The beta angle is now increasing toward a maximum angle of 
76 degrees on 18 November 1999 (DOY 322).

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 0.9 to 1.1 degrees C.  Additional battery performance data for each 
battery on 05 November 1999 and 12 November 1999 are provided in Appendix D.

The clock error ranged from 10.4 to -10.5 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     =     03
%     PEM     =     02
%     HALOE   =     01

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

%     FOT     =     02

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

TRANSPONDER FREQUENCIES:
%     Transponder A:  99/284  -  2287.496981
%     Transponder B:  99/265  -  2287.498700


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 99/315 show the observatory data loss to be 150 hours, 41 
minutes, 19.097 seconds (an increase of 66 hours 45 minutes 27.424 seconds 
since the last report period).  This is a 0.2113 percent data loss which equals 
a 99.7887 percent data capture for the mission.

The increase of 66 hours 45 minutes 27.424 seconds occurred over seven (7) 
days:

7 05 hours 41 minutes 16.064 seconds on Day 309 due to a S/C TR problem.
7 15 hours 24 minutes 12.608 seconds on Day 310 due to a S/C TR problem.
7 19 hours 36 minutes 28.160 seconds on Day 311 due to a S/C TR problem.
7 19 hours 18 minutes 03.968 seconds on Day 312 due to a S/C TR problem.
7 05 hours 58 minutes 43.168 seconds on Day 313 due to a S/C TR problem.
7 00 hours 46 minutes 19.840 seconds on Day 314 due to a S/C TR problem.
7 00 hours 00 minutes 23.616 seconds on Day 315 due to a S/C TR problem.

OTHER SIGNIFICANT EVENTS

UARS SATELLITE OPERATIONS

     Investigation and testing continued with NBTR-B this week.  The Spooling 
test was in progress since Tues., Nov 2.  Tape recorder performance was nominal 
until Fri., Nov 5.  That evening NBTR-B resumed the same failure pattern and 
the FOT was notified.  The FOT came in on Sat, Nov 7 and executed the 4-Mux 
Mode test.  The 4-Mux Mode works in the manner that four of record/playback 
heads record in the forward direction, called Pass 1 while the other 4 heads 
record in the reverse direction, called Pass 2.  If a particular head is 
identified to be anomalous, the data from either Pass 1 or 2 can be isolated 
and used.

The 4-Mux Mode test on Sat, Nov 7 was NOT entirely successful.  Only the data 
from Pass 2 was captured.  The 4-Mux Mode test was attempted two more times on 
Mon., Nov 8 with the same results, Pass 2 data only captured.  This indicated 
that one or more heads on Pass 1 are intermittent.

The test was continued again on Tues., Nov 9 with data captured from both Pass 
1 and 2 with no dump errors observed.  After a day of successful 
record/playback runs, NBTR-B was left in the 4-Mux Mode and scheduled to 
maximize data capture.  To date, both pass 1 and 2 data have been captured with 
no anomalies to report.  The operation is still considered in the test mode, 
therefore TDRSS support will continue to be maximized and the anomaly 
investigation will continue.

The anomaly investigation continues with data analysis, test plans and the 
operational capability.  Additional contractual support has been provided to 
help this anomaly.  Specifically;

- Data analysis has been hindered by the nature of the anomaly.  During the 
anomaly, the frame sync bits don't matched the expected pattern and the 
entire frame is thrown away.  This translates to no data capture.  Without 
data, all of the NBTR-B parameters cannot be analyzed.  Currently an action 
is in place to release the frame sync bit pattern restrictions and process 
all the data, good or bad.
 
- The Test Plans are continually discussed with their value, content and 
hazards reviewed.
 
- An issue under investigation surrounding the operational capability lies 
within the Erase function.  According to the provided operating documentation 
the only way to erase is to place NBTR-B into record.  The Erase function is 
automatically enabled during record but only during the forward direction, or 
Pass 1.  When the recorder switches to Pass 2, Erase is automatically 
disabled.  What this all translates to is that the recorder must be in record 
for four hours to capture two hours of data in a Pass 1 failure scenario.  If 
Pass 1 becomes intermittent, an Erase function could significantly increase 
recorder coverage by eliminating the slow erasure process of recording on all 
of Pass 1 just to erase Pass 2.  For example, Pass 2 may be able to be erased 
in the Wind Mode which is significantly faster than Rec Mode.

- Contractual Support has been appreciated by the investigating FOT.  In 
general, outside support has aided the FOT by providing insight into the 
nature of the anomaly, test plan review, a name database for additional 
contacts and help, data analysis, failure history and capabilities of other 
missions, documentation and much more.

- On Wed, Nov 10, 1999 the RF switch was configured from RHCP to LHCP on the 
transponder at 1500 UTC, from the stored command load.  This gives the 
capability to take MA supports as well as SSA.  The MA service can now be 
scheduled to help fill scheduling gaps and maximize realtime.  In the event 
NBTR-B fails completely, SSA/MA coverage will be the only means for capturing 
the science data.  The RF switch was previously configured to RHCP to reduce 
mutual interference from other mission using LHCP.  Over the past few years the 
mutual interference has diminished.  Since the reconfiguration, no interference 
has been reported.

     The FOT continued it's effort to schedule additional TDRS contact time in 
support of the NBTR B anomaly.  This effort involved extending existing SSA 
events, as well as adding new SSA and MA events, in an attempt to maximize 
real-time communications with the satellite.  Due to the polarization switch of 
transponder B from Right Hand Circular Polar (RHCP) to Left Hand Circular Polar 
(LHCP), all new and rescheduled events (two weeks worth) had to be added using 
LHCP configuration codes.  This all made for a very intensive week of TDRS 
scheduling. 

YEAR 2000 OPERABILITY SUPPORT

All areas identified to or by the Flight Operations Team for Y2K testing have 
been completed.  There are no other areas identified at this time that have not 
been Y2K certified.

MEETINGS

DOY 312, Mon. 10 am, Nov 8, 1999 - A briefing was held on the status of NBTR B.
The operating performance and anomaly trends were discussed.  These discussions 
lead to the identification of contractual engineers with relevant experience.  
Permission was given to contact and update the identified support.

DOY 312, Mon. 2 pm, Nov 8, 1999 - A meeting was held to discuss the status of 
NBTR-B as well as brief Contracted guests to the events of the past few weeks.  
The FOT's test recommendations were discussed.  All were in agreement to the 
tests that the FOT had recommended and the order and condition in which they 
should be completed.  Also agreed upon, was the throwing of the RF switch for 
MA supports and LHCP SSA events.

DOY 313, Tues. 10:30 am, Nov 9, 1999 - A meeting was held to discuss some of 
the details to throw the RF switch.  An implementation schedule for the 
throwing of the RF switch, LHCP for SSA and MA support with GCMR commands were 
discussed.  Additional contract support was present and briefed as to the 
status of NBTR-B.

FUTURE SIGNIFICANT EVENTS

No specific date was agreed upon for UARS Safehold configuration discussions.  
Instead, the Supporting Engineers involved will be contacted every two weeks to 
determine if either the Flight Operations Team or Supporting Engineers have any 
new developments that should be discussed in a group.  It is expected that one 
more meeting will be held before Y2k as an update to UARS safehold expectations 
for the new century.

The Leonid Shower is expected and planned for November 17 through 18, 1999.  
Special operational procedures are in place.  The FOT will be present to 
oversee the implementation of the plan.

UARS has tested and prepared for the Year 2000 event.  Special considerations 
have been made in preparation for a non nominal 1999 to 2000 transition.


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 12 November 1999

ORBIT       AOS          NO.      SUBSYS     REASON
-----       ---         ---      ------     -------
44563     310/1325     99-368     OBC       Clk Adj 0.00 to 20.6 msec/day
44591     312/0939     99-369     OBC       Clk Adj 20.6 to 0.00 msec/day
44518     314/0502     99-370     OBC       Clk Adj 0.00 to 20.6 msec/day
44624     314/1352     99-371     HALOE     Power OFF
44627     314/1954     99-329     PEM       Power ON AXIS 1 & 2
44645     315/2322     99-372     PEM       Power OFF AXIS 2

_________________________________________________________________________

                               APPENDIX B
                     OUT-OF-LIMITS & ALERTS OCCURRENCES
                        Week ending 12 November 1999

The following Out-Of-Limits occurrences were detected:

MNEMONIC        STATE     DESCRIPTION          ORBITS
---------       -----     ------------         ------
HRPTSPBIMON     R-LO      PTS PB I Monitor     44586
HRPSEPBIMON     R-LO      PSE PB I Monitor     44586
HATBAT          Y-HI      HALOE Bolo Temp      44620-22

The following ALERT occurrences were detected:

MNEMONIC                  DESCRIPTION         ORBITS
---------                ------------         ------
No Alerts to report this report period.
_________________________________________________________________________

                             APPENDIX C
                CLOCK & SOLAR ARRAY RATE CORRECTIONS
                   Week ending 12 November 1999

                  CLOCK DRIFT RATE ADJUSTMENTS

ORBIT            TIME                  CLOCK RATE CHANGE
-----            ----                  -----------------
44563     310/13:28 (06 Nov 99)     from 00.0 to 20.6 msec/day
44591     312/09:52 (08 Nov 99)     from 20.6 to 00.0 msec/day
44618     314/05:16 (10 Nov 99)     from 00.0 to 20.6 msec/day

                            APPENDIX D
                  UARS BATTERY PERFORMANCE DATA
                  Week ending 12 November 1999

     05 Nov 1999 - GMT Day 309 Beta = 30.3 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    -89.6/-106.4   -3.05/-4.94   +0.0/+0.0   16.3    0.000      0.0
2    +28.0/-11.2    +5.47/+3.87  +29.6/-15.2  25.3    1.086     21.2
3    +33.6/-22.4    +4.51/+2.60  +29.2/-15.2  25.1    1.083     21.0

     12 Nov 1999 - GMT Day 316 Beta = 60.8 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     -72.8/-95.2   -3.68/-4.94   +0.0/+0.0   16.3    0.000      0.0
2     +22.4/-11.2   +3.87/+2.60  +24.0/-14.4  26.7    1.030     18.4
3     +22.4/-22.4   +2.92/+1.66  +23.2/-14.8  26.6    1.027     17.9


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


                                APPENDIX E
                           UARS ANOMALY REPORTS
                        Week ending 12 November 1999

                       NEW ANOMALY REPORTS GENERATED
AR NO.    SUBSYS    ORBIT     TIME     TTR     PROBLEM/DATA LOSS
------    ------    -----     ----     ---     -----------------
99-080    WINDII    44600   312/2323   N/A     WINDII Error Code 03
99-082    FOT       44638   315/1201   21565   Wrong DSID for MA event

                ANOMALY CLOSURE INFORMATION RECEIVED
AR NO.    SUBSYS    ORBIT     TIME     TTR     PROBLEM/DATA LOSS
------     ------   -----     ----     ---     -----------------
99-080     WINDII   44600   312/2323   N/A     WINDII Error Code 03
99-082     FOT      44638   315/1201   21565   Wrong DSID for MA event

            ANOMALY INVESTIGATION REPORTS GENERATED
AR NO.     SUBSYS     ORBIT   TIME     TTR     PROBLEM/DATA LOSS
------     ------     -----     ----   ---     -----------------
                       No new reports generated

                      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 Receiving 512 PB
99-081     FOT               November   14170   Generic Late Acquisition


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