UARS Weekly Status Report

21 January 2005




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                UARS WEEKLY STATUS REPORT - 21 JAN 2005

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

SOLSTICE resumed normal operations this week (doy 015) after performing 
day only operations in support of the yaw maneuver. Otherwise, the 
instrument continues to perform well, taking solar data on all 
available orbital tracking periods. An average of 56% of data were 
returned this week accounting for 388 minutes of solar observing time 
per day.

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

SUSIM successfully gathered daily mid (1.1 nm) resolution, MgII,
occultation, solar pointing offset, and continuous monitoring scans
for time periods with UARS telemetry or tape recording.

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

     The new PEM2K:: is now fully configured and functional.  All communication
paths should function as normal.

     HEPSA data files are version 2.  Currently, HEPSA data between 1991274 
and 2004259 has been reprocessed and archived at the GSFC DAAC.  HEPSA data
between 2004260 and 2004269 are currently being processed.

     MEPS data files are version 1.  Processed MEPS data files at the DAAC 
archive are between 1991274 and 2004239.  MEPS data between 2004240 and 2004259
are waiting for archival at the DAAC.

     PEM continues to receive NMC data files from NOAA.  No problems have
been encountered.

     The PEM data from the GUVI conjunction periods may be found at 
http://wwwpem.space.swri.edu/guvi-pem.html.  The additional electron data for 
the October and November storms of 2003 has been moved and is now located at 
http://climatology.space.swri.edu/uars_fromRudy.html.  For those users of 
SDDAS, update your UARS Meta data and these data times will appear
with full functionality.  Proton data from these storms are now located at
http://climatology.space.swri.edu/UARS_images_from_Rudy_(Apr._2004).html

     Requests have been received for storm spectral data.  Overview plots were 
produced and these plots may be found on the web at
http://climatology.space.swri.edu/UARS_images_postedJune2004.html
for the storms of October 29 of 1991, November 8-9 of 1991, April 6-7 of 2000, 
March 31 - April 1 of 2001, April 11-12 of 2001, November 6-7 of 2001, and 
November 11-12 of 2001.

*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.

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

The MPG continues to serve as the point-of-contact for UARS
instrument operations in support of the Science Traceability
Mission of UARS.

Daily processing of instrument Daily Activity Plans continues
with no problems.

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

Nothing received.
                  
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FOT
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                           REPORTING PERIOD

This  report covers 08 January 2005 (Orbit 72940, GMT Day 008) through
15 January 2005 (Orbit 73045, GMT Day 014).


                         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
       HALOE         009/2239      72969     POWER OFF
       SUSIM         010/2206      72984     POWER OFF
       SOLSTICE      010/2312      72984     FULLTIME TO DAY-ONLY OPS
       HRDI          011/0237      72986     DAY ONLY TO LOW POWER
       WINDII        011/2203      72999     B/U A OFF

A Reverse-to-Forward Yaw Around maneuver (number 136) was successfully
executed in Orbit 73009 beginning 012/ 15:12:27Z and completing at
012/ 15:49:37Z on 12 January 2005.  All instruments were in their off
or standby mode (except for SOLSTICE in day-only).  Due to the SA
position at 269 degrees, the effective night length of the spacecraft
after the maneuver was approximately 55.71 minutes.  Post maneuver
analysis of data indicate that during the Yaw Around, the end-of-night
load bus voltage was 26.08 volts and the average depths of discharge
(DODs) on Batteries 2 and 3 were approximately 20.04 and 18.87 percent
respectively.  The next (forward-to-reverse) YAW is scheduled for 12
February 2005 (DOY 043).


The beta angle ranged between the angles of 0.0 degrees to 08.3
degrees for this report period.  The beta angle is now increasing
towards a maximum angle of 39 degrees on 27 January 2005 (DOY 027).

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 stable with a temperature delta
between Battery 2 and Battery 3 of 1.59 to 1.60 degrees C.  Additional
battery performance data for each battery on 07 January 2005 and 14
January 2005 are provided in Appendix D.

The clock error ranged from 10.6 to -10.0 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         =    02

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

    FOT       =    07
    HALOE     =    01
    SUSIM     =    01
    SOLSTICE  =    01
    HRDI      =    01
    WINDII    =    01


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

    FOT       =    02

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


                        GROUND SYSTEM OPERATION

One (1) operational support problem occurred this period.  Anomaly
Reports are included in Appendix E.

The data loss calculations are no longer being supplied by Data
Capture Facility (DCF).


                       OTHER SIGNIFICANT EVENTS


                       UARS SATELLITE OPERATIONS


This week the FOT started noticing the differential voltage on battery
3 drop on 11 January 2005.  Around 1600 GMT the differential voltage
broke -200 mV.  The online crew was told to continue to monitor the
value closely.  For the remainder of the day, it seemed to come back
down periodically, so there wasn't much concern.

Then around 0800 GMT on 12 January 2005 the differential voltage hit 
-274 mV.  All instruments were in there off or standby state for the
upcoming yaw maneuver, so load shedding was not an option.  The FOT
continued to track the anomaly and was told to report if the
differential voltage hit -300 mV.  This happened around 012/1330 GMT,
which was the orbit before the yaw maneuver.  The NASA power branch
engineer was notified and the FOT went forward with the maneuver.  As
a precautionary measure, the FOT disabled the MLS heater operations
(012/1431 GMT), so that the batteries could recover better following
the yaw.  After the yaw the differential hit -318 mV and the following
orbit got to -336 mV.  The power branch engineer reviewed the data and
recommended that FOT continue to monitor the data closely.  In the
late afternoon the value had come back to a value of -254 mV, but then
by around 012/2300 GMT it climbed back up to -302 mV.  The FOT then
started to terminate supports early to conserve power during
spacecraft night.  That remained in effect into the following day and
preliminary passes showed some beneficial results.  However, the
differential did not subside long and dropped back to -302 mV.

The FOT hoped that as the beta angle improved the phenomena would go
away.  However, by Friday (DOY 014) it was apparent that the
differential voltage was not going to stop moving more negative.  It
reached -380 mV and the decision was made to go to VT-7.  Strict
guidelines were given to the ops crew, so that an overcharging
condition did not occur.  The differential came down immediately in VT-
7 and performed nominally, so the batteries remained in VT-7 into the
weekend

The FOT also continued their CMS software acceptance testing this
week.  The goal for completion is no later than end of January 2005.




                               MEETINGS


The FOT met with the NASA power branch engineers on 14 January 2005 to
discuss the short and long term plans to manage the differential
voltage on battery 3.



                       FUTURE SIGNIFICANT EVENTS

The next UARS Yaw slew is scheduled for 12 February 2005 (DOY 043).
This maneuver will be a Forward to Reverse Flight maneuver (Northern
Hemisphere viewing).


Attachments:   Appendix A,     Real-time Command 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 14 January 2005

ORBIT   AOS        NO.      SUBSYS      REASON
-----   ---        ---      ------      ------
72969   009/2239   05-005   HALOE       POWER OFF (YAW)
72980   010/1656   05-006   OBC/CLK     CLK ADJ FR 0.0 TO -20.6 MSEC/DAY
72984   010/2206   05-007   SUSIM       POWER OFF
72984   010/2312   05-008   SOLSTICE    FULLTIME TO DAY-ONLY OPS
72986   011/0237   05-009   HRDI        HRDI DAY ONLY TO LOW POWER
72999   011/2203   05-010   WINDII      B/U A OFF
73003   012/0454   05-011   OBC/CLK     CLK ADJ FR -20.6 TO 0.0 MSEC/DAY
73009   012/1431   05-013   MACS        YAW REV TO FWD
73009   012/1431   05-012   MPS         MLS HEATER ACTIONS DISA
73009   012/1509   05-012   MPS         MLS HEATER ACTIONS DISA
73010   012/1557   05-013   MACS        YAW REV TO FWD
73017   013/0355   05-014   MPS         MLS HEATER ACTIONS ENAB
73028   013/2108   05-015   MPS         PMON ACTION 23 CLEAR/ENABLE
73040   014/1631   05-016   MPS         VT L6 TO L7


                              APPENDIX B
                  OUT-OF-LIMITS & ALERTS OCCURRENCES
                      Week ending 14 January 2005

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
--------     -----------                          ------
OBSPMACENA23 PMON ACTION 23 OOL                   73008
OBSPMGPOOL31 PMON GROUP 31 OOL                    73008



                              APPENDIX C
                 CLOCK & SOLAR ARRAY RATE CORRECTIONS
                      Week ending 14 January 2005

                     CLOCK DRIFT RATE ADJUSTMENTS

ORBIT          TIME                   CLOCK RATE CHANGE
-----          -----                  -----------------
72980          010/1708               CLK ADJ FR 0.0 TO -20.6 MSEC/DAY
73003          012/0454               CLK ADJ FR -20.6 TO 0.0 MSEC/DAY

                              APPENDIX D
                     UARS BATTERY PERFORMANCE DATA
                      Week ending 14 January 2005

     07 January 2005 - GMT Day 007 Beta = 22.2 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    -700.0/-700.0 -3.05/-4.31  +00.0/+00.0  07.0     0.00      0.0
2      22.4/ -33.6 +6.44/+5.47  +29.6/-14.0  26.2     1.04     20.0
3     -11.2/-190.4 +5.15/+3.87  +28.0/-13.2  26.2     1.03     19.0

     14 January 2005 - GMT Day 014 Beta = 08.3 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    -700.0/-700.0 -3.05/-4.31  +00.0/+00.0  07.0     0.00      0.0
2      67.2/  00.0 +6.43/+4.82  +28.0/-12.8  26.4     1.03     18.9
3     -33.6/-313.6 +4.50/+2.91  +26.0/-11.2  26.4     1.04     17.5


     V/T LEVEL CHANGES
ORB#           AOS TIME   LVL FR-TO
-----          --------   ---------
73040          014/1631   LV6 -> LV7


                              APPENDIX E
                         UARS ANOMALY REPORTS
                      Week ending 14 January 2005

                     NEW ANOMALY REPORTS GENERATED
AR NO.    SUBSYS    ORBIT     TIME      CDS       PROBLEM/DATA LOSS
------    ------    -----     ----      ---       -----------------
05-001    FOT       72997     011/1914  30832     Generic Late Acquisition
05-002    MPS       73008     012/1251  NA        BATT 3 DiffV High

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

                ANOMALY INVESTIGATION REPORTS GENERATED
AIR NO.   SUBSYS    ORBIT     TIME      CDS       PROBLEM/DATA LOSS
------    ------    -----     ----      ---       -----------------
-None this report period.

                         OPEN ANOMALY REPORTS
AR NO.    SUBSYS    ORBIT     TIME      CDS       PROBLEM/DATA LOSS
------    ------    -----     ----      ---       -----------------
05-001    FOT       See List  Jan 05    30832     Generic Late Acquisition
05-002    MPS       73008     012/1251  NA        BATT 3 DiffV High