UARS Weekly Status Report

25 September 1998





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                UARS WEEKLY STATUS REPORT - 25 Sep 1998

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

With the exception of the ~8 hour unscheduled off period due to the spacecraft
under-voltage condition on Thursday (98267), SOLSTICE continues to operate 
normally, collecting solar data on all available orbital tracking periods and 
stellar calibration observations, whenever possible.

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

Nothing received.

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

     The PEM zenith boom instruments were active from September 15 through 
September 19, when the zenith instruments were deactivated and the PEM/AXIS 
was activated.  The PEM/AXIS was deactivated on September 23 due to low
spacecraft power.  During these activation periods, PEM produced both electron 
and ion energy deposition from in situ measurements when the zenith 
spectrometers were active and produced energy deposition from electrons, 
inverted from measured X-rays obtained in 16 pixels, from the Atmospheric
X-ray Imaging Spectrometer.

     GSFC has proposed an OBC operation plan for the activation of PEM boom 
instruments during the daylight portions of every orbit.  This OBC operation 
plan is accepted by PEM.  PEM has proposed a series of test procedures for 
activation and is waiting response from GSFC.  PEM is also waiting for GSFC
scheduling and implementation of its operation test procedures.

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

HALOE continues successful operations with all engineering parameters being
nominal and the science data continues to be of excellent quality.  HALOE
was off for approximately 5.5 hours due to the low voltage situation on
September 24th.  HALOE is scheduled to be turned off near the end-of-day
September 26, 1998 for the upcoming yaw. 

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

MLS is scheduled to begin operations on Oct 6 and operate though Oct 10. The
MLS team will operate the instrument in a mode for diagnosing the reoccurance
of slips in the antenna scan mechanism, and to attempt to find a method of
operating the instrument which minimizes the impact of these slips on
scientific data.

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

Nothing received.

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

Nothing received.

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

Routine processing of instrument Daily Activity Plans continues 
with no other problems.  The MPG continues to assist the Project 
Scientist with the scheduling of instrument operations.

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

The CDHF has received a total of 420 CD-ROM requests as of 25-September-1998.
There were seven orders received and shipped.

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.           
             52 days HAL (4.80) PROD (L1)    (1873R-1500C-36F=337L)
             31 days HAL (4.80) PROD (L3)    (1873R-858C=1015L)
             87 days SOL (4.62) PROD (L2-L3) (2349R-1601C=748L)
              8 days SUS (7.00) ENG          (65R-65C=0L)
              2 days WIN (5.10) ENG          (4R-4C=0L)

The CDHF loaded July DAAC data into the DAAC Transfer Tables.

The CDHF executed and monitored a SOLSTICE test day during standalone time.  
The test permited investigation of a wallclock time inflation problem 
reported by the SOLSTICE Representative.
    
CDHF pending software upgrades: IDL 5.1, OpenIngres.                      
                  
***********
FOT
***********

REPORTING PERIOD

This report covers 12 September 1998 (Orbit 38265, GMT Day 255) through 18 
September 1998 (Orbit 38369, GMT Day 261).


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          257/2252       38309        Off
       ACRIM         257/2252       38309        On
       SUSIM         258/0010       38310        On
        PEM          258/0512       38313        Zeps On
       WINDII        259/0014       38325        On

The beta angle ranged between 52.4 degrees to 41.5 degrees for this report 
period.  The beta angle is now decreasing toward a minimum angle of -2.0 
degrees for the yaw on 29 September 1998 (DOY 272).

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 1.2 degrees C.  Additional battery performance data 
for each battery on 11 September 1998 and 18 September 1998 are provided in 
Appendix D.

The clock error ranged from 11.2 to -11.3 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.

%     ALERTS         =     00
%     OUT-OF-LIMITS  =     03

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

%     FOT     04
%     MLS     01
%     ACRIM   01
%     PEM     01
%     SUSIM   01
%     WINDII  01

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:  98/210  -  2287.496941
     Transponder B:  98/211  -  2287.499161


GROUND SYSTEM OPERATION

No 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 98/260 show the observatory data loss to be 
21 hours, 06 minutes, 41.140 seconds (an increase of 1 minute and 39.136 
seconds since last report period).  This is a 0.0345 percent data loss 
which equals a 99.9655 percent data capture for the mission.


The increase of 1 minute and 39.136 seconds occurred over three days:
7 1:27.776 minutes on Day 254 due to line errors and data gap,
7 10.336 seconds on Day 255 due to data gap, and
7 1.024 seconds on Day 257 insufficient overlap and hit in the data.

The cause of the data gap(s) is under investigation to exclude tape 
recorder involvement.


OTHER SIGNIFICANT EVENTS

UARS SATELLITE OPERATIONS

FOT continues to improve a power profile for UARS based on the current 
status of the Modular Power System.

The possible impacts of the Leonid meteorite shower in November 1998 are 
being investigated.

YEAR 2000 OPERABILITY SUPPORT

UARS Test and Training Simulator (UTTS) - No change.

User Planning System (UPS) - No change.

Multi Satellite Operations Control Center (MSOCC) - The FOT attended a 
meeting on 17 September to discuss the Year 2K compatibility of the POCC AP 
software, as well at the UARS Test and Training Simulator (UTTS). The Year 
2K POCC/AP test team had several questions related to FOT.  In addition, 
the test team pointed out a few Year 2K related AP software problems, and 
asked the FOT whether or not they could live with the problems.  The FOT 
agreed to investigate the test teamUs findings and respond by early next 
week.

Command Management System (CMS) - The FOT successfully processed a Year 2K 
User Antenna View (UAV) file on the back-up CMS this week.  The file 
appeared to process without any problems, and a report of the generated ODB 
depicted a proper roll-over from 1999 to 2000.  The FOT also received a 
Year 2K PSAT file, but cannot process it until the corresponding S/C 
Orbital Events file is received (due to a CMS processing dependency).  
Finally, the FOT received 3 corrected UARS OBC ephemeris files.  However, 
the new files still did not contain a full 72 hours worth of data and hence 
could not be processed by the CMS.  FDF was notified of the problem (once 
again) and stated that they would correct these files and re-send them next 
week.

Flight Dynamics Facility (FDF) - The FOT is still waiting on a big portion 
of the planning aid data files.  The pending files are either still being 
generated by FDF or are hung up at the test FORMATS system in Greentech 4.  
As soon as the FOT gets a complete set of planning aids, Year 2K testing 
can proceed.  However, it should be noted that due to the lack of FDF 
supplied planning aids, the CMS test team will be under a severe time 
constraint to meet the September 30th deadline.

OBC PMON FLIGHT SOFTWARE UPDATE

Flight Software - Complete.

Ground Support Software - Complete.

Verification Testing - Complete.

Uplink - Supporting data (tapes, etc.) for the UARS Test and Training 
Simulator (UTTS) for scenario generation were accumulated on 14 and 15 
September.  The scenario, executed on 16 September, provided a more 
accurate representation of what the telemetry should look like before, 
during and after the  software uplink.  The simulation of the uplink was 
successful.  This simulation will be repeated a day prior to uplink.

IP NETWORK TESTING

Space Network (SN) - No change.

Testing with the NCC 98 system to support routine flight operations is 
being planned.

Deep Space Network (DSN) and Ground Spaceflight Tracking and Data Network 
(GSTDN) - Performed a DSN data flow from Johnson Space Center (JSC) using 
pre recorded UARS data.  1kbps data and 32kbps I channel real-time data 
were received.  Command was not possible because the AP can not generate 
the correct destination code for the JSC simulator - not in UARS AP 
software.  JSC attempted to send 32k OBC dump data but was unsuccessful.  
JSC may not be able to simulate that type of data.


UARS PROPULSION MODULE B/D THRUSTER LINE FILL

The B/D thruster refill effort continues.  The Eaton Latch Valve test 
report is still being reviewed by the UARS FOT.

UARS RE-ENGINEERING - TELEMETRY PROCESSING

Flight operations is providing support to the re-engineering effort to 
process the UARS telemetry on the TOMS/EP control center computer system.  
Two MSOCC terminals were removed from the operations console on 10 
September and replaced with two multi-purpose terminals driven by the re-
engineering system.  The re-engineering system is being RrunS in parallel 
to the MSOCC system for evaluation purposes.

UARS COMMAND RE-HOST PHASE 1 DEMONSTRATION

Flight operations continues to support the update of the Lockheed Martin 
SCS-21 control center system.  Development continues on the system.  A 
Phase 1 feasibility demonstration of the SCS-21 system supporting UARS is 
scheduled for 22 September 1998.


MEETINGS

The FOT attended a meeting on 17 September 1998 to discuss the Year 2K 
compatibility of the POCC AP software, as well at the UARS Test and 
Training Simulator (UTTS).

UARS and TOMS/EP participated in the GSFC On-Orbit Operations Independent 
Study Team (IST) interviews with the GSFC operational mission teams on 17 
September 1998.  Presentations in handout form were prepared according to 
the study teamUs outline.

The next battery telecon is scheduled for 22 September 1998 at 1:00 pm.


FUTURE SIGNIFICANT EVENTS

The next UARS Yaw Around Maneuver is scheduled for scheduled for 29 
September 1998.

The United States Naval Observatory (USNO) issued  a Time Service 
announcement advising that the International Earth Rotation Service (IERS) 
will retard UTC time by 1.0 second at the end of December 1998. This means 
the addition of one leap second as the last second of 1998.

The next annular solar eclipse will occur on 16 February 1999 over the 
Indian Ocean, Australia and the South Pacific Ocean.


PERSONNEL CHANGES

Kathy Palmer, Flight Operations Director, submitted her resignation 
effective 24 September 1998.

Deryck Chetram, Flight Operations Director, submitted his resignation 
effective 25 September 1998.


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 18 September 1998

ORBIT      AOS        NO.    SUBSYS       REASON
-----      ---        ---    ------       -------  
38304    257/1529   98-342   OBC     Clk Adj fr 20.6 to 0.00 msec/day
38309    257/2252   98-343   MLS     Power OFF
38309    257/2252   98-344   ACRIM   Power ON
38310    258/0010   98-345   SUSIM   Power ON
38313    258/0512   98-346   PEM     ZEPS Power On
38325    259/0014   98-347   WINDII  Power ON
38330    259/0751   98-348   OBC     Clk Adj fr 0.00 to 20.6 msec/day
38333    259/1306   98-349   RTS     SUSIM Heater Cycle
38367    261/1919   98-350   OBC     Clk Adj fr 20.6 to 0.00 msec/day



_______________________________________________________________

                               APPENDIX B
                  OUT-OF-LIMITS & ALERTS OCCURRENCES
                      Week ending 18 September 1998

MNEMONIC     STATE      DESCRIPTION                        ORBITS
---------    -----      ------------                       ------
QTSISAIF     Y-HI     SSPP Baseplate by SISA I/F   38280-317
QTSSPPMX     Y-HI     SSPP -X Thermostat           38282
NBRECBI      Y-HI     NBTR B Current               38282,97,303,330



The following ALERT occurrences were detected:

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



_______________________________________________________________

                               APPENDIX C
                 CLOCK & SOLAR ARRAY RATE CORRECTIONS
                      Week ending 18 September 1998


                      CLOCK DRIFT RATE ADJUSTMENTS

     ORBIT              TIME                 CLOCK RATE CHANGE
     -----              ----                 -----------------
     38304     257/15:32 (14 Sept 98)     from 20.6 to 00.0 msec/day
     38330     259/07:59 (16 Sept 98)     from 00.0 to 20.6 msec/day
     38367     261/19:28 (18 Sept 98)     from 20.6 to 00.0 msec/day


_______________________________________________________________

                               APPENDIX D
                    UARS BATTERY PERFORMANCE DATA
                      Week ending 18 September 1998


     11 Sept 1998 - GMT Day 254 Beta = 52.4 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  -3.05/-4.31  +0.0/ +0.0    18.1    0.000    0.0
2   +39.2/-11.2   +5.79/+4.51 +26.0/-16.0    25.4    1.024   21.8
3   +44.8/-11.2   +4.51/+3.23 +25.2/-16.0    25.3    1.027   21.3

     18 Sept 1998 - GMT Day 261 Beta = 41.5 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  -3.30/-2.73  +0.0/ +0.0    18.1    0.000    0.0
2   +67.2/ 0.0    +5.71/+6.44 +28.8/-16.0    24.6    1.022   22.5
3   +33.6/-22.4   +4.77/+5.47 +28.4/-16.8    24.6    1.023   22.1


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



                               APPENDIX E
                         UARS ANOMALY REPORTS
                      Week ending 18 September 1998


                     NEW ANOMALY REPORTS GENERATED
  AR NO.   SUBSYS       ORBIT      TIME       TTR    PROBLEM/DATA LOSS
  ------   ------       -----      ----       ---    -----------------
98-060     FOT         38313     258/0512     N/A    TAC Crashed


                 ANOMALY CLOSURE INFORMATION RECEIVED
  AR NO.   SUBSYS       ORBIT      TIME       TTR    PROBLEM/DATA LOSS
  ------   ------       -----      ----       ---    -----------------
98-059     FOT         38224     253/14:10   20186  NO CMD/IP SUPPORT
98-060     FOT         38313     258/05:12          TAC 8 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
  ------   ------       -----      ----       ---    -----------------
98-057     FOT     Sept 98     See list      14170  GENERIC LATE ACQ