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UARS WEEKLY STATUS REPORT - 27 February 1998
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SOLSTICE
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SOLSTICE continues to operate normally, collecting solar data on all
available orbital tracking periods and stellar calibration observations,
whenever possible.
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SUSIM
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SUSIM successfully gathered its normal solar, offset, and occultation
scan data during this past week without apparent problems.
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PEM
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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.
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HALOE
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HALOE was powered off end-of-day February 19, 1998. All engineering
parameters were nominal and the science results continue to be excellent.
HALOE is scheduled to power on beginning-of-day March 4, 1998.
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MLS
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Nothing received.
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HRDI
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HRDI is currently off, next expected turn on is March 7th.
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WINDII
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Nothing received.
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MPG
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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
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E-mail was sent on February 25 to UARS customers regarding the March 20-23
and April 24-27 power outages in building 23 where the CDHF resides.
The CDHF has received a total of 372 CD-ROM requests as of 27-February-1998.
There were two orders received and shipped.
Current day data created in the month of December 1997 has been loaded to
the DAAC transfer tables for HALOE, HRDI, NMC, PEM, and UKMO.
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-954C=425L)
119 days MLS (4.90) PROD (1297R-681C=616L)
1 day CLAES (7.0) ENG (17R-1C=16L)
The CDHF continues development of a list of Year-2000 compliant software
needed by the CDHF.
Pending software upgrades: IDL 5.0, OpenIngres, UCSS.
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FOT
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REPORTING PERIOD
This report covers 14 February 1998 (Orbit 35121, GMT Day 045 through 20
February 1998 (Orbit 35225, GMT Day 051).
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
HALOE 050/2326 35210 Off
MLS 051/0051 35211 On
HRDI 051/2316 35225 Off
The beta angle is now decreasing toward a minimum angle of 0.0 degrees on
25 February 1998 (DOY 056).
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 24.0 V end-of-night (EON) load bus voltage.
Battery temperatures are stable with a temperature delta between Battery 2
and Battery 3 of 1.4 degrees C. Additional battery performance data for
each battery on 14 February 1998 and 20 February 1998 are provided in
Appendix D.
The clock error ranged from -11.3 to +10.3 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 = none
% OUT-OF-LIMITS = none
The following real-time command sheets were executed for the listed
operational element(s) during this report period (see Appendix A).
% FOT 03
% HALOE 01
% HRDI 01
% MLS 01
UARS Anomaly Reports initiated during this report period are listed in
Appendix E and summarized below.
% FOT 02
TRANSPONDER FREQUENCIES:
Transponder A: 98/041 - 2287.497104
Transponder B: 98/042 - 2287.499330
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 98/050 show the observatory data loss to be
20 hours, 42 minutes, 7.540 seconds (an increase of 1.184 seconds since
last reported). This is a 0.0368 percent data loss which equals a 99.9632
percent data capture for the mission.
The increase of 1.184 seconds occurred on Day 044 due to hits in the data.
Operational processing of level-0 telemetry analysis files continues in
parallel on both the UMPGAL (new MPG Alpha machine) and CDHF computer
systems. Level-0 file transfer failures (between CDHF and UMPGAL) occurred
on 20 February at about 01:45 UTC. These transfer failures occurred due to
reconfiguration of the UMPGAL computer to support the MODnet interface. No
file transfer failures have occurred since the reconfiguration, although
the file transfer rate appears to be drastically lower than before (file
transfers take 10 to 20 times longer). The low data transfer rates are
being investigated.
OTHER SIGNIFICANT EVENTS
Work on the upgrade of the OBC Power Monitor (PMON) software continued. The
code is being RdebuggedS.
Flight Dynamics Facility (FDF) requested updated parameters to improve the
projected UARS altitude calculation. The UARS/FOT furnished the current
UARS spacecraft mass and frontal spacecraft/solar array drag area to
facilitate this effort on 19 February 1998.
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 25 February
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 batteries and their performance.
The UARS orbit altitude is dropping slowly and a drag makeup orbit adjust
will probably be required in 1999.
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 20 February 1998
ORBIT AOS NO. SUBSYS REASON
----- --- --- ------ -------
35148 046/1956 98-055 OBC/CLK Clk Adj 20.6 to 00.0
35177 048/1838 98-056 OBC/CLK Clk Adj 00.0 to 20.6
35203 050/1152 98-057 OBC/CLK Clk Adj 20.6 to 00.0
35210 050/2326 98-058 HALOE Power OFF
35211 051/0051 98-059 MLS Power ON
35225 051/2316 98-060 HRDI Power OFF
_______________________________________________________________
APPENDIX B
OUT-OF-LIMITS & ALERTS OCCURRENCES
Week ending 20 February 1998
MNEMONIC STATE DESCRIPTION ORBITS
--------- ----- ------------ ------
none this report period
The following ALERT occurrences were detected:
MNEMONIC DESCRIPTION ORBITS
--------- ------------ ------
none this report period
APPENDIX C
CLOCK & SOLAR ARRAY RATE CORRECTIONS
Week ending 20 February 1998
CLOCK DRIFT RATE ADJUSTMENTS
ORBIT TIME CLOCK RATE CHANGE
----- ---- -----------------
35148 046/20:01 (15 Feb 98) from 20.6 to 00.0 msec/day
35177 048/18:46 (17 Feb 98) from 00.0 to 20.6 msec/day
35203 050/12:01 (19 Feb 98) from 20.6 to 00.0 msec/day
_______________________________________________________________
APPENDIX D
UARS BATTERY PERFORMANCE DATA
Week ending 20 February 1998
14 Feb 1998 - GMT Day 045 Beta = 48.9 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/-4.62 +0.0/ +0.0 18.6 0.000 0.0
2 +44.8/ -5.6 +5.79/+4.51 +28.8/-15.2 26.1 1.027 21.0
3 +56.0/ -22.4 +4.51/+2.92 +28.0/-16.0 25.9 1.024 20.5
20 Feb 1998 - GMT Day 051 Beta = 21.2 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 -2.73/-3.99 +0.0/ +0.0 18.6 0.000 0.0
2 +22.4/ -44.8 +7.74/+5.15 +33.6/-16.4 24.2 1.015 24.1
3 +33.6/ -22.4 +6.44/+3.87 +32.0/-16.4 24.0 1.017 23.2
V/T LEVEL CHANGES
ORB# TIME LVL FR-TO
----- -------- ----------
no changes
APPENDIX E
UARS ANOMALY REPORTS
Week ending 20 February 1998
AR NO. SUBSYS ORBIT TIME TTR PROBLEM/DATA LOSS
------ ------ ----- ---- --- -----------------
98-007 FOT 35162 047/1820 14170 Generic Late Acquisition
98-007 FOT 35207 050/1831 14170 Generic Late Acquisition
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