UARS Weekly Status Report

03 August 2001




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                UARS WEEKLY STATUS REPORT - 03 AUG 2001

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

SOLSTICE continues to operate normally, taking solar data on all available
orbital tracking periods and stellar calibration observations whenever
possible. We continue to gather enough data to meet all the SOLSTICE
science objectives during this period of reduced tape recorder operations.

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

Thanks a generous donation of power by PEM, we were able to plan for
nearly all of our final (?) lamp calibration.  We are most grateful.
The sequence of corresponding reference channel solar scans begins today.

SUSIM has completed its daily solar scans this past week during
periods of predicted UARS telemetry.

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

Nothing received.

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

Nothing received.

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

Nothing received.

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

Nothing received.

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

Nothing received.

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

Nothing received.

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

MPG distributed a revised copy of the Instrument Schedule
for the next yaw period. On  01 August the MPG participated 
in the UARS Monthly Status Review meeting.  

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

Nothing received.
                  
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FOT
***********

                        REPORTING PERIOD

This report covers 21 July 2001 (Orbit 53896, GMT Day 202) through 27 July 2001 
(Orbit 54000, GMT Day 208).

                      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           202/0746      53900      Power Off
          PEM           202/0929      53901      Day Only
          PEM           202/1526      53905      Full Time
          PEM           202/1849      53907      Day Only
          PEM           202/2029      53908      Power Off
          PEM           202/2350      53910      Day Only
          HALOE         208/0004      53986      Power On
          PEM           208/0610      53898      AXIS On


The beta angle ranged between the angles of 75.7 degrees to 54.1 degrees for 
this report period.  The beta angle is now decreasing towards a minimum angle 
of 0 degrees on 09 August 2001 (DOY 221).

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 1.2 to 1.3 degrees C.  Additional battery performance data for each 
battery on 20 July 2001 and 27 July 2001 are provided in Appendix D.

The clock error ranged from Ð11.3 to 6.3 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  =  02
¥      ALERTS         =  00

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

¥      FOT            =  04
¥      HALOE          =  01
¥      PEM            =  09

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

¥      FOT            =  01

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

TRANSPONDER FREQUENCIES:
· Transponder A:  00/316  - 2287.496493
· Transponder B:  01/119  - 2287.499116


                       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 01/207 show the observatory data loss to be 302 hours, 55 
minutes, 48.256 seconds. This shows a loss of 06 minutes and 13.088 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 increase of 06 minutes and 13.088 seconds occurred over five (5) days:
· 35.168 seconds on Day 202 due to a Data Hit.
· 1 minute and 16.256 seconds on Day 204 due to Data Hits
· 4 minutes and 08.000 seconds on Day 205 due to bad weather TTR# 23977
· 13.664 seconds on Day 207 due to a Data Hit


                         OTHER SIGNIFICANT EVENTS

                        UARS SATELLITE OPERATIONS

The UARS FOT attended a UARS All-Hands Meeting on Wednesday, July 25,2001.  At 
this meeting the FOT and all UARS entities were informed that NASA headquarters 
has stated (verbally) that there will be no funds available to operate UARS 
past this September.  This statement is unofficial at this time, but the FOT 
has begun work on the decommissioning plan, which will end all UARS operations. 
All development activities will be continued until this decision is finalized; 
however, they may be discontinued pending the outcome from NASA headquarters.

The FOT changed the safehold configuration on board this week.  The previous 
configuration had been sun-pointing safehold, which only gave a few orbits of 
time before the batteries would suffer severe overcharging and most likely end 
the mission.  The current configuration is now earth-pointing safehold with the 
earth sensor off.  This will allow the spacecraft to keep pitching over at one 
revolution per orbit and keep the other axis stable for a minimum of 3-4 
orbits.  Given the almost realtime status of UARS operations this should give 
enough time to react to a safehold situation.

                               MEETINGS

The UARS FOT attended a UARS All-Hands Meeting on Wednesday, July 25,2001.
The UARS FOT attended a UARS SERB/TAC RS Meeting on Wednesday, July 25,2001.
The UARS FOT attended a Safehold Working Group Meeting on Thursday, July 26, 
2001.

                       FUTURE SIGNIFICANT EVENTS

The next UARS Yaw slew is scheduled for 08 August 2001 (DOY 220).  This 
maneuver will be a Forward to Reverse 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 27 July 2001

ORBIT      AOS         NO.        SUBSYS      REASON
-----      ---         ---        ------      ------
53900      202/0746    01-465     PEM (Z/H)  Power OFF
53901      202/0929    01-466     PEM (Z/H)  Power ON DAY ONLY
53905      202/1526    01-467     PEM (Z/H)  Power ON FULL TIME
53907      202/1849    01-468     PEM (Z/H)  Power ON DAY ONLY
53908      202/2029    01-469     PEM (Z/H)  Power OFF
53910      202/2350    01-470     PEM (Z/H)  Power ON DAY ONLY
53911      203/0106    01-471     PEM (Z/H)  TO FULL TIME OPS
53924      203/2132    01-472     OBC/CLK    Clk Adj from 4.20 to 20.6 msec/day
53980      207/1449    01-473     MACS       Safehold Reconfig
53982      207/1809    01-474     NBTR       NOOPS D-208
53986      208/0004    01-475     PEM        ZEPS HEPS TO DAY ONLY
53986      208/0004    01-476     HALOE      Power ON
53898      208/0610    01-477     PEM        Power ON AXIS
53997      208/1810    01-478     NBTR       D209 noops

______________________________________________________________________________

                             APPENDIX B
                 OUT-OF-LIMITS & ALERTS OCCURRENCES
                      Week ending 27 July 2001

The following Out-Of-Limits occurrences were detected:

MNEMONIC      STATE      DESCRIPTION               ORBITS
--------      -----      -----------               ------
CDUNRG28      Y-LO       CDH UNREGULATED 28V       53900      
HRPSEQBIMON   Y-HI       HRDI QB CURRENT MONITOR   53899,900      


The following ALERT occurrences were detected:

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

_______________________________________________________________________________

                              APPENDIX C
               CLOCK & SOLAR ARRAY RATE CORRECTIONS
                      Week ending 27 July 2001

                    CLOCK DRIFT RATE ADJUSTMENTS

ORBIT      TIME          CLOCK RATE CHANGE
-----      -----         -----------------
53924      203/2132      Clk Adj from 4.20 to 20.6 msec/day      
_______________________________________________________________________________


                              APPENDIX D
                    UARS BATTERY PERFORMANCE DATA
                      Week ending 27 July 2001


      20 July 2001 - GMT Day 201 Beta = 77.4 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    -1.79/-3.05   +0.0/+0.0      12.2      0.000    0.0
2    +11.2/-89.6      +2.60/+1.34   +14.4/-15.2    31.5      0.096    13.3
3    +16.8/-44.8      +1.97/+1.03   +14.0/-15.6    31.5      0.095    13.3


      27 July 2001 - GMT Day 208 Beta = 54.1 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      12.0     0.000     0.0
2    +11.2/-67.2     +4.51/+3.23   +24.8/-15.2    25.0     1.050     17.9
3    +22.4/-44.8     +3.55/+2.29   +24.0/-14.4    24.8     1.050     17.0


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

______________________________________________________________________________

                                   APPENDIX E
                          UARS ANOMALY REPORTS
                        Week ending 27 July 2001

                     NEW ANOMALY REPORTS GENERATED
AR NO.      SUBSYS      ORBIT      TIME         TTR      PROBLEM/DATA LOSS
------      ------      -----      ----         ---      -----------------
01-044      FOT         53941      205/0004     23997    Late Acq. due to 
                                                         weather at W.S.


                  ANOMALY CLOSURE INFORMATION RECEIVED
AR NO.      SUBSYS      ORBIT      TIME         TTR      PROBLEM/DATA LOSS
------      ------      -----      ----         ---      -----------------
01-044      FOT         53941      205/0004     23997    Late Acq. due to 
                                                         weather at W.S.


                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
------      ------      -----      ----         ---      -----------------
01-041      FOT      see list      July 01      14170     Generic Late 
                                                           Acquisition




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