UARS Weekly Status Report

5 December 1997





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                UARS WEEKLY STATUS REPORT - 05 December 1997

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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 successfully gathered its normal solar, offset, and occultation
scan data during this past week without apparent problems.

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

     PEM/AXIS was active from November 26 through December 4.  PEM zenith 
spectrometers were activated on December 4.  PEM produced energy deposition 
profiles from electrons inverted from the AXIS X-ray measurements and
is currently generating profiles of the electron and proton precipitation
from spectrometer data.

     PEM is awaiting evaluation by GSFC of its proposed activation procedure.
The minimal configuration for PEM AUX activation is the zenith VMAG, MEPS1, 
MEPS2, and HEPS1 units, only.  This configuration is driven by the capabilities 
of the spacecraft OBC and may increase if OBC program area increases.  PEM 
activation is proposed to be OBC driven when there exists plenty of power to 
operate PEM.  It is anticipated that the OBC will activate PEM on the daylight 
portions of every orbit.

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

HALOE was power on December 3, 1997, a day earlier than scheduled to
provide correlative data to the shuttle instrument SOLSE.  All instrument
parameters are nominal and the science data is being processed.

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

Nothing received.

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

HRDI is currently off.  Next turn-on is scheduled for Dec. 8.

Next week Prof. Paul Hays and Dr. David Ortland will be attending the Fall
AGU meeting in San Francisco to present the following papers.

"HRDI: A Study of Dynamics"

"Analysis of temperatures and winds in the mesosphere and lower
thermosphere measured by HRDI"

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

  WINDII has been operating since November 24, and is operating
with no problems. We can't say "normally", as it is running
with the active temperature control system off, in order to
reduce the power requirements, and particularly the warmup
surge that would otherwise occur. The temperature seems rather
stable, even without active control. 

   Five WINDII team members are attending the AGU meeting, and
contributing to the UARS Aeronomy session. 

***********
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.

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

The CDHF has received a total of 350 CD-ROM requests as of 05-December-97. One
new CD-ROM order was received and two were shipped this week.    

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.         
                  20 days PEM (3.32) Prod (1350R-635C=715L)
                                
The CDHF continues to monitor and query the catalog for UKMO data gaps.
The catalog is now up to date except for UARS DAYS 2263 and 2264 and we have
requested that these days be sent.

The CDHF supported CLAES calibration tables and other file management issues
related to their upcoming delivery.

The CDHF will be implementing line tests to RACs with poor performance, in an 
effort to log network throughput to various sites.

Pending software upgrades: IDL 5.0, OpenIngres.
                   
***********
FOT
***********

REPORTING PERIOD

This report covers 21 November 1997 (Orbit 33864, GMT Day 325) through 28 
November 1997 (Orbit 33967, GMT Day 332).


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       328/0124     33894     ZEPS off
    WINDII     328/0631     33897       On
    WINDII     328/0816     33898       Off
    WINDII     328/1600     33903       On
     HRDI      329/2059     33921       Off
     PEM       330/0139     33924     AXIS on
     HRDI      330/1715     33934     Off, low

The beta angle reached a maximum angle of 78.1 degrees on 27 November 1997 (DOY 
331).  The beta angle is now decreasing toward a minimum angle of 0.0 degrees
on 17 December 1997 (DOY 351).

Relative Time Sequences (RTSs) 12 and 13 were modified and uplinked to the 
spacecraft on 26 November 1997 (see Other Significant Events section) to 
correct the compensation heater cycling scheme.

The WINDII turn-on procedure on 23 November 1997 was interrupted due to 
unavailability of a reference microprocessor load (see Ground System section).  
The problem was investigated, rectified, and WINDII turn-on was successfully 
completed on 24 November 1997 (328/1600).

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 27.2 end-of-night (EON) load bus voltage.  Battery 
temperatures are stable with a temperature delta between Battery 2 and Battery 
3 of 0.7 degrees C.  Additional battery performance data for each battery on 
22 November 1997 and 28 November 1997 are provided in Appendix D.

The clock error ranged from -9.8 to +10.2 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            =     02
%     OUT-OF-LIMITS     =     10

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

%     FOT     04
%     HRDI    03
%     PEM     02
%     WINDII  03

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

%     FOT     04

TRANSPONDER FREQUENCIES:
     Transponder A:  97/301 - 2287.497086
     Transponder B:  97/302 - 2287.499098


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 97/331 show the observatory data loss to be 20 hours, 41 
minutes, 02.292 seconds (no change).  This is a 0.0382 percent data loss which 
equals a 99.9618 percent data capture for the mission.

Relative Time Sequence (RTS) 13 was updated to include heater disable commands 
for compensation heaters 19, 20, and 23.  RTS 12 was modified to for 
compensation heater 18Us A side turn on instead of having both the A and B side 
turn on as in the previous version.

The WIRELOAD procedure used to turn-on WINDII Rhung-upS when the reference 
PWIHCNTL file could not be found on the system.  Investigation revealed that 
the FOT was not informed that new microloads were submitted the previous week.  
WINDII operations was contacted and the situation resolved.  New load files 
were generated and placed on the AP Prime Pack.  The WIRELOAD procedure was 
updated to match the filenames of the new loads submitted by WINDII.

Modifications to the OBCSTF resident POCC database were initiated this week.  
Several minor modifications are planned and a new database (version 65) will be 
tested and released before the next yaw maneuver scheduled for 17 December 1997.

The FOT is still working out the details of participating in the IP return-link 
telemetry test that the network is conducting.

Flight Dynamics Facility (FDF) continues the generation process for a new Star 
Catalog to fix the invalid precession rate for star 48000001.

No testing of the new CMS software release (R7B1V2) occurred this week.

Investigation of the stored command verification problem - time to complete - 
associated with Applications Processor (AP) software release 10.08 continued.  
The cause has been identified, but rectifying the problem continues.


OTHER SIGNIFICANT EVENTS

During power-off of HRDI (due to low power) on 25 November 1997, the FOT 
noticed that the HRDI compensation heater (#19) was not cycling properly.  
Further investigation showed that the HALOE compensation heater (#20) was also 
not cycling properly (both were being kept on during spacecraft solar array 
night).  These heaters were supposed to be turned off at end-of-day via PMON 
execution of RTS-13, which contains operational and compensation heater ROFFS 
commands.  More investigation then showed that the latest version of RTS-13 
did not have the compensation heater off commands for heaters 19, 20, and 23 
(HRDI, HALOE, and WINDII).  RTS-12 (holding the heater RONS commands) was also
discovered to contain an additional, unnecessary, heater command for 
compensation heater #18 (SUSIM).

Apparently, the correct versions of RTS-12 and RTS-13 were not reloaded 
following simultaneous operation of MLS and HALOE in late October.  During this 
time, the SSPP instruments were powered off, and heater control for these 
instruments was performed via several different versions of RTS-12 and RTS-13.  
However, when the SSPP instruments were powered back on, the original versions 
of RTS-12 and RTS-13 were not reloaded.  As there is no way to verify via 
telemetry which RTS version is on-board, the discrepancy was not noted.  
Unfortunately, the faulty RTSs resulted in slightly increased night heater
load, which was also not noted, because of the large number of other 
operational changes taking place.  These heater loads probably account for the 
difficulty the FOT has experienced since the end of October in meeting the 
planned instrument schedule.

The correct versions of RTS-12 and RTS-13 were reloaded immediately upon 
discovery of the missing commands on Tuesday, 25 November 1997 (329/22:36 UTC, 
Orbit 33922).  Recovery of additional power was immediate, and the power 
subsystem has been stable since then.

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 17 December 1997 
at 311/132708.

The UARS orbit altitude is dropping slowly and a drag makeup orbit adjust will 
probably be required in mid-1998.


FACILITIES

no change


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 28 November 1997

ORBIT        AOS         NO.     SUBSYS               REASON
-----        ---         ---     ------               -------  
33894     328/0124     97-585     PEM     Power Off ZEPS
33897     328/0631     97-586    WINDII   Power On Completed
33894     328/0124     97-587     OBC     Clk Adj fr 41.2 to 20.6 msec/day
33898     328/0816     97-588    WINDII   Power OFF
33903     328/1600     97-589    WINDII   Power ON
33912     329/0645     97-590     OBC     Clk Adj fr 20.6 to 41.2 msec/day
33921     329/2059     97-591     HRDI    Power OFF, QB OFF
33922     329/2236     97-592     RTS     New RTSUs 12 and 13 Loaded
33922     329/2236     97-593     PSU     Comp HTRUs 19 and 20 Disabled
33924     330/0139     97-594     PEM     Power On AXIS
33934     330/1715     97-595     HRDI    HRDI to low power mode
33936     330/2026     97-596     HRDI    HRDI htr delay to 25 amp-min


_______________________________________________________________

                              APPENDIX B
                  OUT-OF-LIMITS & ALERTS OCCURRENCES
                       Week ending 28 November 1997

MNEMONIC      STATE        DESCRIPTION                ORBITS
---------     -----        ------------               ------
OBSSOC2       Y-LO     Battery 2 Current SOC     33866,880-2,86-87
PWTMPS1       Y-HI     Mod Temp 1                33866,880,87
ACHTRI2       R-LO     ACRIM Heater Current 2    33886-967
ACHTRV2       R-LO     ACRIM Heater Voltage 2    33886-967
OBSBATVEON2   Y-LO     Battery 2 voltage at EON  33896,99
OBSBATVEON3   Y-LO     Battery 3 voltage at EON  33896,99
OBSVLBEON     Y-LO     Load Bus Volts at EON     33896,99
OBSBATVEON2   R-LO     Battery 2 voltage at EON  33897-8,909-22
OBSBATVEON3   R-LO     Battery 3 voltage at EON  33897-8,909-22
OBSVLBEON     R-LO     Load Bus Volts at EON     33897-8,909-22


The following ALERT occurrences were detected:

MNEMONIC                 DESCRIPTION                 ORBITS
---------                ------------                ------
WIERRLIMIT         WINDII Software Error Code        33896
WISRCBBS           WINDII Source Broad Band          33904



                                APPENDIX C
                 CLOCK & SOLAR ARRAY RATE CORRECTIONS
                       Week ending 28 November 1997

                      CLOCK DRIFT RATE ADJUSTMENTS

     ORBIT              TIME                 CLOCK RATE CHANGE
     -----              ----                 -----------------
     33894     328/01:44 (24 Nov 97)     from 41.2 to 20.6 msec/day
     33912     329/06:51 (25 Nov 97)     from 20.6 to 41.2 msec/day


_______________________________________________________________

                               APPENDIX D
                    UARS BATTERY PERFORMANCE DATA
                       Week ending 28 November 1997

     22 Nov 1997 - GMT Day 326 Beta = 64.6 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  -3.84/-4.94   +0.0/ +0.0    18.7    0.000    0.0
2   +11.2/ -22.4  +4.89/+3.23  +23.2/-16.0    25.9    1.020    20.9
3   +56.0/ -11.2  +3.70/+2.29  +22.4/-15.2    25.8    1.020    20.0

     28 Nov 1997 - GMT Day 332 Beta = 77.2 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  +728.0/+728.0  -2.94/-3.68   +0.0/ +0.0    18.7    0.000     0.0
2   +11.2/ -22.4  +2.98/+1.56  +16.8/-16.4    27.4    1.037    14.4
3   +22.4/ -22.4  +2.29/+0.94  +16.0/-16.0    27.2    1.040    13.7


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

_______________________________________________________________
                                   APPENDIX E
                              UARS ANOMALY REPORTS
                            Week ending 28 November 1997

  AR NO.   SUBSYS   ORBIT       TIME       TTR        PROBLEM/DATA LOSS
 ------    ------   -----       ----       ---        -----------------
97-119     FOT     33904     328/1739    14170   Generic Late Acquisition
97-119     FOT     33917     329/1523    14170   Generic Late Acquisition
97-122     FOT     33937     330/2239     N/A    TAC Crashed
97-123     FOT     33945     331/1154     N/A    TAC Crashed

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


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