UARS Weekly Status Report

10 April 1998





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                UARS WEEKLY STATUS REPORT - 10 APRIL 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 successfully gathered its normal solar, offset, and occultation
scan data this week without apparent problems.  SUSIM has recently begun
taking an second scan of the wavelength region containing the Mg II
absorption feature.  It is expected that the noise level of the Mg II
index will be reduced though the inclusion (at some time in the future)
of this new data in its calculation.

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

     PEM is currently off.

     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 powered on April 8, 1998.  All engineering parameters are nominal
and the science channels are within the expected operating range.

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

The MLS instrument has been powered off since Mar 29. MLS is scheduled to
begin north viewing operations on Apr 15.

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

HRDI is currently operating.  We expect to be operating till April 15.
Operations are normal.

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

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

The CDHF has received a total of 381 CD-ROM requests as of 10-April-1998.
There were no orders received 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.           
                  25 days PEM (3.32) PROD (1379R-1099C=280L)
                  54 days MLS (4.90) PROD (1297R-1279C-18F=0L)
                   5 days CLAES (7.0) ENG (72R-40C-1F=31L)
                2178 days ATT (7.2) PROD (2178R-439C=1739L)
              
The CDHF completed setup of database compression, to run during GRAVE shifts.
This moves the UCSS downtime for partial compresses to offshift hours, causing
less disruption to daytime users for UCSS downtime.  Full compresses will
still be performed once a month on a scheduled Tuesday.  Archives with UCSS
up, are still performed on Thursdays.

The CDHF developed software to assist with the monitoring of the UARS RACs.
When a node has been down for an hour, CDHF operators will send e-mail to a 
distribution list, requesting that the NISN/NI NOC open a trouble ticket and
investigate.  

The CDHF continued work on network and RAC configurations.  The reports 
include contacts, decnet addresses, ip addresses, locations, phone numbers, 
and email adresses.  Work also continues in providing NISN the RACs that
need Multinet, and writing up the UARS Network Requirements.
                  
***********
FOT
***********

REPORTING PERIOD

This report covers 28 March 1998 (Orbit 35750, GMT Day 087) through 03 
April 1998 (Orbit 35853, GMT Day 093).


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
         MLS           089/0136        35780          Off

The beta angle reached a minimum angle of 0.0 degrees on 02 April 1998 (DOY 
092).  The beta angle is now increasing toward a maximum angle of 45.7 
degrees on 19 April 1998 (DOY 109).

A Forward-to-Reverse Yaw Around maneuver (number 67) was successfully 
executed in Orbit 35833 at 13:47:22 UTC on 02 April 1998.  The SSPP 
Instruments (ACRIM, SOLSTICE, and SUSIM) were enabled.  Post maneuver 
analysis of data indicate that during the Yaw Around, the end-of-night load 
bus voltage was 24.5 volts and the average depths of discharge (DODs) on 
Batteries 2 and 3 were approximately 22.5 and 22.0 percent respectively.

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 24.5 V end-of-night (EON) load bus voltage.  
Battery temperatures are stable with a temperature delta between Battery 2 
and Battery 3 of 1.1 degrees C.  Additional battery performance data for 
each battery on 28 March 1998 and 03 April 1998 are provided in Appendix D.

The clock error ranged from -12.8 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.

%     ALERTS          =   none
%     OUT-OF-LIMITS   =   08

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

%     FOT    02
%     HRDI   02
%     MLS    01
%     SUSIM  01

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

%     FOT    01

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


TRANSPONDER FREQUENCIES:
     Transponder A:  98/062  -  2287.496945
     Transponder B:  98/062  -  2287.497010


GROUND SYSTEM OPERATION

One (1) 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 98/085 show the observatory data loss to be 
20 hours, 42 minutes, 33.140 seconds (no increase since last report 
period).  This is a 0.0362 percent data loss which equals a 99.9638 percent 
data capture for the mission.

The FOT attempted to perform return link IP testing this week, but was 
unable to do so due to configuration problems with the UARS/MSOCC IP 
conversion device.  Further testing will be attempted next week.  In 
addition, the FOT is in the process of finalizing the configuration 
requirements for the IP Forward link test which will utilize the UTTS 
instead of the actual UARS spacecraft.  To accommodate this test, the 
network will have to be configured in a command loop-back mode so commands 
sent by the FOT will travel through the IP network, up to TDRS, through the 
RFSOC, and to the simulator.  Actual testing of this configuration is 
expected to occur within the next two weeks.  A deadline for complete 
switch-over to the IP network has been set for mid July 1998.

The FOT continued making modifications to the OBCSTF resident POCC 
database.  These changes will be incorporated into the next operational 
database release, version 66.

OTHER SIGNIFICANT EVENTS

Work on the upgrade of the OBC Power Monitor (PMON) software continued.  
Continued database work for new PMON software.  Defined new RTS and PDB 
assignments to support PEM day-only operation.  Five new RTS allocations 
will be required, holding 179 commands.  Three previously allocated, but 
unused, RTSs, and eight unused PDBs will also be used.  These new RTSs and 
PDBs will be included with the new PMON software uplink.

FOT continues to support CNMOS in their efforts to make necessary software 
changes (MSOCC, CMS, DCF, etc.) to support the year 2000 rollover.

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 05 May 1998.

A second building 23 power outage is scheduled from about 12 p.m., 24 April 
1998, until about 12 p.m., 27 April 1998.

UARS Flight Operations plans to attend the Program Experience portion of 
the Space Power Workshop at JPL in April 1998.  UARS FOT plans on 
presenting an overview of the UARS power subsystem and its performance.

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 03 April 1998

ORBIT       AOS        NO.     SUBSYS      REASON
-----       ---        ---     ------     -------  
35778   088/2233     98-117    OBC     Clk Adj fr 0.00 to 20.6 msec/day
35780   089/0136     98-118    MLS     Power OFF
35796   090/0321     98-119    OBC     Clk Adj fr 20.6 to 0.00 msec/day
35801   090/1106     98-120    HRDI    HRDI Heater Delay to 125 Amp/Min
35813   091/0513     98-121    HRDI    HRDI Heater Delay to 175 Amp/Min
35839   092/2328     98-122    SUSIM   reload instrument commands


_______________________________________________________________

                               APPENDIX B
                  OUT-OF-LIMITS & ALERTS OCCURRENCES
                      Week ending 03 April 1998

MNEMONIC      STATE     DESCRIPTION                   ORBITS
---------     -----     ------------                  ------
HRIFESURVTMP  Y-HI   IFE Survival Heater Temp       35750-1
HRRADTEMP     Y-HI   IFE Radiator Temp              35751
QTSISAIF      Y-HI   SSPP Baseplate SISA I/F        35756-853
HRPSEQBIMON   Y-HI   PSE Quiet Bus Current Monitor  35771
SOSTMPRNTRN   Y-LO   Solstice Entrance Temperature  35821,31,36
ACTEMPANA2    Y-LO   Temp Sensor Electronics        35831-36
HRPSEQBIMON   Y-HI   PSE Quiet Bus Monit            35831
WIEUTEMP      Y-LO   WINDII EU Temperature          35750-853


The following ALERT occurrences were detected:

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



                               APPENDIX C
                 CLOCK & SOLAR ARRAY RATE CORRECTIONS
                      Week ending 03 April 1998

                      CLOCK DRIFT RATE ADJUSTMENTS

     ORBIT              TIME                 CLOCK RATE CHANGE
     -----              ----                 -----------------
     35778     088/22:38 (29 Mar 98)     from 00.0 to 20.6 msec/day
     35796     090/03:26 (31 Mar 98)     from 20.6 to 00.0 msec/day


_______________________________________________________________

                               APPENDIX D
                    UARS BATTERY PERFORMANCE DATA
                      Week ending 03 April 1998

     28 Mar 1998 - GMT Day 087 Beta = 18.9 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   +84.0/  +0.0  +7.09/+5.47  +31.6/-14.4   24.5    1.025     23.1
3   +67.2/  -5.5  +5.47/+4.19  +30.4/-16.0   24.5    1.024     22.5

      03 Apr 1998 - GMT Day 093 Beta =  4.5 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/-3.99   +0.0/ +0.0    18.4     0.000     0.0
2 +112.0/  +0.0  +5.79/+4.51  +31.2/-14.4    24.5     1.024    22.4
3  +84.0/  -5.6  +4.51/+3.55  +30.4/-15.2    24.5     1.021    21.8


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



                               APPENDIX E
                         UARS ANOMALY REPORTS
                      Week ending 03 April 1998


                           NEW ANOMALY REPORTS GENERATED
  AR NO.   SUBSYS    ORBIT      TIME       TTR     PROBLEM/DATA LOSS
  ------   ------    -----      ----       ---     -----------------
98-014     FOT     35830    092/08:48            Tac 4 Crash


                      ANOMALY CLOSURE INFORMATION RECEIVED
  AR NO.   SUBSYS    ORBIT      TIME       TTR     PROBLEM/DATA LOSS
  ------   ------    -----      ----       ---     -----------------
98-009     FOT     March 1998           14170    Genric Late Acq. 
98-014     FOT     35830    092/08:48            Tac 4 Crash


                      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
  ------   ------     -----     ----       ---     -----------------
98-015    Generic Late Acq for April 1998. Open until 31 April 1998.


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