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UARS WEEKLY STATUS REPORT - 19 JAN 2001
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>>>>> An Update on UARS Attitude Control <<<<<
Attitude of the UARS spacecraft is being controlled by 3-axis
magnetometer (TAM) data which are being processed by the on-board
computer. The plan is to rely on on-board processing of TAM data
for attitude control with the Fine Sun Sensor (FSS) in monitor
mode. However, at the high solar beta angles which are being
encountered between 16 January and 25 January the Sun is out of
the Fine Sun Sensor field of view. Our indications are that S/C
attitude is being maintained within specifications using only the
3-axis magnetometer. The FOT would welcome any feedback from
instrument teams about spacecraft attitude as they have observed
it.
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SOLSTICE
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SOLSTICE is in good health, collecting 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.
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SUSIM
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SUSIM performed its daily solar scans of the sun during periods of
predicted UARS telemetry.
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ACRIM
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Nothing received.
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PEM
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Nothing received.
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HALOE
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Nothing received.
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MLS
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Nothing received.
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HRDI
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HRDI continues to operate normally.
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WINDII
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Nothing received.
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MPG
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The instrument operations schedule for the next yaw period,
9 February to 15 March, has been distributed. Daily
processing of instrument Daily Activity Plans continues
with no problems.
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CDHF
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Nothing received.
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FOT
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REPORTING PERIOD
This report covers 06 January 2001 (Orbit 50955, GMT Day 006) through 12
January 2001 (Orbit 51060, GMT Day 012).
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 011/0014 51031 AXIS ON
The beta angle ranged between the angles of 30.4 degrees to 51.7 degrees for
this report period. The beta angle is now increasing towards a maximum angle
of 77 degrees on 21 January 2001 (DOY 021).
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 2.2 and 1.9 degrees C respectively. Additional battery performance data
for each battery on 05 January 2001 and 12 January 2001 are provided in
Appendix D.
The clock error ranged from 12 to 12.4 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 = 01
¥ ALERTS = 00
The following real-time command sheets were executed for the listed operational
element(s) during this report period (see Appendix A).
¥ FOT = 27
¥ PEM = 01
UARS Anomaly Reports initiated during this report period are listed in Appendix
E and summarized below.
¥ FOT = 01
Four (4) Anomaly Report remained OPEN at the end of this report period (see
Appendix E).
TRANSPONDER FREQUENCIES:
· Transponder A: 00/315 - 2287.496493
· Transponder B: 00/314 - 2287.498584
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 01/011 show the observatory data loss to be 300 hours, 08
minutes, 41.256 seconds. This shows an overall increase of 0 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.
· There was no data loss for the week.
OTHER SIGNIFICANT EVENTS
UARS SATELLITE OPERATIONS
UARS continues to maintain attitude control on TAM alone this week. The FSW
patch of the nonorthogonal alignment was successfully uplinked on 10 January
2001. The patch improved the TAM's performance, as expected, and UARS is set
to fly through the high beta period with the TAM as its only input to UFLTR.
More fine tuning of the TAM is needed before it will be operating at its
maximum effectiveness, but it has proven to be stable enough to maintain all
science requirements.
MEETINGS
The FOT attended a TAM Attitude Meeting on 08 January 2001.
The FOT attended a TAM Software Patch Meeting on 09 January 2001.
The FOT attended a TAM Attitude Meeting on 10 January 2001.
The FOT attended a UARS Retrieval Meeting on 10 January 2001.
FUTURE SIGNIFICANT EVENTS
The next UARS Yaw slew is scheduled for 09 February 2001 (DOY 040). This
maneuver will be a Reverse to Forward 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 12 January 2001
ORBIT AOS NO. SUBSYS REASON
----- --- --- ------ ------
50958 006/0409 01-021 OBC Clk Adj 0.0 to -20.6 msec/day
50960 006/0708 01-020 NBTR NOOPS D006
50960 006/0738 01-022 OBC Clk Adj -20.6 to 20.6 msec/day
50965 006/1611 01-023 ACS TAM ALIGNMENT
50967 006/1800 01-024 NBTR NOOPS D007
50979 007/1348 01-025 OBC Clk Adj 20.6 to 0.0 msec/day
50982 007/1808 01-026 NBTR NOOPS D008
50990 008/0711 01-026 NBTR NOOPS D008
50994 008/1433 01-027 ACS TAM ALIGNMENT
50997 008/1909 01-028 NBTR NOOPS D009
51000 009/0011 01-029 ACS MAGMOD Time Correction
51005 009/0712 01-028 NBTR NOOPS D009
51009 009/1352 01-030 ACS TAM ALIGNMENT
51009 009/1434 01-031 POCC FILE XFER
51012 009/1910 01-032 ACS TAM ALIGNMENT
51012 009/1910 01-033 NBTR NOOPS D010
51020 010/0750 01-033 NBTR NOOPS D010
51024 010/1354 01-034 FSW FSW Update for TAM
51025 010/1544 01-035 OBC Reset Status Buffer
51027 010/1911 01-036 NBTR NOOPS D011
51031 011/0014 01-037 PEM AXIS POWER ON
51032 011/0215 01-038 OBC Clk Adj 0.0 to 20.6 msec/day
51035 011/0722 01-036 NBTR NOOPS D011
51041 011/1731 01-039 OBC TAM ALIGNMENT
51042 011/1911 01-040 NBTR NOOPS D012
51050 012/0716 01-040 NBTR NOOPS D012
51055 012/1439 01-041 ACS TAM ALIGNMENT
51057 012/1913 01-042 NBTR NOOPS D013
__________________________________________________________________________
APPENDIX B
OUT-OF-LIMITS & ALERTS OCCURRENCES
Week ending 12 January 2001
The following Out-Of-Limits occurrences were detected:
MNEMONIC STATE DESCRIPTION ORBITS
-------- ----- ----------- ------
HATBAT Y-HI HALOE Bolometer Area Temp 51056-60
The following ALERT occurrences were detected:
MNEMONIC DESCRIPTION ORBITS
-------- ----------- ------
-None this report period
_______________________________________________________________________________
APPENDIX C
CLOCK & SOLAR ARRAY RATE CORRECTIONS
Week ending 12 January 2001
CLOCK DRIFT RATE ADJUSTMENTS
ORBIT TIME CLOCK RATE CHANGE
----- ----- -----------------
50958 006/0410 Clk Adj 0.0 to -20.6 msec/day
50960 006/0740 Clk Adj -20.6 to 20.6 msec/day
50979 007/1354 Clk Adj 20.6 to 0.0 msec/day
51032 011/0210 Clk Adj 0.0 to 20.6 msec/day
___________________________________________________________________________
APPENDIX D
UARS BATTERY PERFORMANCE DATA
Week ending 12 January 2001
05 Jan 2001 - GMT Day 005 Beta = 30.4 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 14.2 0.000 0.0
2 +0.0/-44.8 +5.47/+4.51 +16.0/-15.2 25.9 1.030 21.0
3 +11.2/-22.4 +4.51/+3.55 +15.6/-15.2 25.8 1.030 20.9
12 Jan 2001 - GMT Day 012 Beta = 51.7 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 14.2 0.000 0.0
2 +11.2/-95.2 +5.15/+2.92 +25.6/-15.2 25.1 1.050 19.9
3 +22.4/-44.8 +3.87/+1.97 +25.6/-15.6 25.1 1.040 19.7
V/T LEVEL CHANGES
ORB# TIME LVL FR-TO
----- ---------- ----------
-no changes V/T 5
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APPENDIX E
UARS ANOMALY REPORTS
Week ending 12 January 2001
NEW ANOMALY REPORTS GENERATED
AR NO. SUBSYS ORBIT TIME TTR PROBLEM/DATA LOSS
------ ------ ----- ---- --- -----------------
01-002 FOT 51005 009/0749 14170 Generic Late Acquisition
ANOMALY CLOSURE INFORMATION RECEIVED
AR NO. SUBSYS ORBIT TIME TTR PROBLEM/DATA LOSS
------ ------ ----- ---- --- -----------------
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
------ ------ ----- ---- --- -----------------
00-053 FOT 50168 319/1113 23157 Late Acquisition
00-054 FOT 50280 326/2147 23187 RESET PTP /2:39 32K
00-056 FOT 50584 347/0502 23302 Premature LOS
01-002 FOT see list Jan 01 14170 Generic Late Acquisition
SEVNTFW01/02