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UARS WEEKLY STATUS REPORT - 21 Sep 2001
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SOLSTICE
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SOLSTICE continues to operate normally, taking 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 turned off for the yaw-around on 9/10 and was repowered on 9/14.
Otherwise SUSIM completed its daily solar scans this past week during
periods of predicted UARS telemetry.
As requested, we have verified NRT files built on the PACOR-A system
versus the CDHF versions. Except for still unexplained differences
in the headers, they were found to be acceptable. We still expect
to review similarly built level 0 data but as of this writing, NONE
have been received. Since these files have essentially the same
record structure, we are optimistic that there to be no problems.
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ACRIM
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Nothing received.
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PEM
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***** ALL PEM COMMUNICATION SHOULD NOW BE THROUGH THE PEM2K:: NODE *****
PEM is saddened by the shutdown of UARS and appreciates all of the
efforts of GSFC in the past and present of UARS. PEM stands ready for the
September 24 shutdown date.
At the present time, PEM energy deposition from its spectrometers is not
being generated. Recent data configuration changes have affected PEM software
causing multiple failures. These failures are being reviewed by the PEM team.
In order to correct for new telemetry requirements, PEM will need to update
processing code with a patch delivery. The delivery patch may include changes
which would allow the PEM software to execute on a DEC Alpha machine. GSFC is
helping PEM with some DEC Alpha particulars which have caused PEM level 3
code to fail on DEC Alpha machines (software below level 3 executes on the
DEC Alpha). Currently, PEM has requested GSFC assistance with compiling for
the DEC Alpha since the GSFC executables run on the Alpha and SwRI's compiled
versions do not.
Updated HEPS calibration parameters have been finalized and are ready for
delivery. Updated MEPS quality calibration files have been finalized and are
ready for delivery. Level 3 software errors, discovered by Dr. Dean Pesnell,
have been fixed; his suggestions have been incorporated with in the PEM
production code. Both updated HEPS and MEPS calibration data, along with the
Level 3 code changes, will influence the in-situ energy deposition predictions,
so new versions of PEM energy deposition Level 3 files will be generated.
*Beginning of power orbit day (PEM activation): array current >5 amps, array
voltage >53.5 volts, and battery current >2.0 amps.
End of power orbit day (PEM deactivation): time in power orbit day >4 minutes,
array current <9 amps, and battery currents <0.2 amps.
Power orbit day variation: ~39-40 min at yaw to ~50-51 min at maximum beta.
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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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Nothing received.
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WINDII
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Nothing received.
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MPG
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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 08 September 2001 (Orbit 54631, GMT Day 251) through 14
September 2001 (Orbit 54735, GMT Day 257).
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 252/2319 54660 Power OFF
SUSIM 253/2320 54675 Power OFF
SUSIM 257/1250 54729 Power ON
A Reverse-to-Forward Yaw Around maneuver (number 102) was successfully executed
in Orbit 54685 beginning 254/15:18:38 and completing at 254/15:55:48 on 11
September 2001. The SOLSTICE instrument was in day only and all other
instruments were in their off or standby mode (including HRDI and PEM). Due to
the SA position at 269 degrees, the effective night length of the spacecraft
after the maneuver was approximately 57.1 minutes. Post maneuver analysis of
data indicate that during the Yaw Around, the end-of-night load bus voltage was
23.8 volts and the average depths of discharge (DODs) on Batteries 2 and 3 were
approximately 22.1 and 23.4 percent respectively. The next (forward-to-
reverse) YAW is scheduled for 17 October 2001 (DOY 290).
The beta angle ranged between the angles of 12.8 degrees to 10.1 degrees for
this report period. The beta angle is now increasing towards a maximum angle
of 54 degrees on 30 September 2001 (DOY 273).
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 0.6 to 0.7 degrees C. Additional battery performance data for each
battery on 7 September 2001 and 14 September 2001 are provided in Appendix D.
The clock error ranged from Ð11.9 to 9.8 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 = 00
¥ ALERTS = 00
The following real-time command sheets were executed for the listed operational
element(s) during this report period (see Appendix A).
¥ FOT = 03
¥ PEM = 01
¥ HRDI = 01
¥ SOLSTICE = 02
¥ SUSIM = 02
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: 00/316 - 2287.496493
· Transponder B: 01/243 - 2287.499091
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 01/256 show the observatory data loss to be 303 hours, 10
minutes, and 47.024 seconds. This shows a loss of 1 minute and 33.520 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.
The increase of 1 minute and 33.520 seconds occurred over five (5) days:
· 13.744 seconds on Day 252 due to a Data Hit
· 13.840 seconds on Day 253 due to a Data Hit
· 20.112 seconds on Day 254 due to a Data Hit
· 23.360 seconds on Day 255 due to a Data Hit
· 22.464 seconds on Day 256 due to a Data Hit
OTHER SIGNIFICANT EVENTS
UARS SATELLITE OPERATIONS
In addition to completing the yaw maneuver successfully, the FOT executed all
of its realtime command and operational scenario testing of the new TAC
replacement systems. A meeting is scheduled on 18 September 2001 to review the
test results and determine a schedule for completing the tasks remaining before
the system can become operational. The TAC replacement is needed to provide
the front end interface for the future ground system and possibly a new
trending analysis system. These changes are needed to try to reduce the cost
of UARS, given its current budgetary issues.
MEETINGS
The UARS FOT attended no meetings during this report period.
FUTURE SIGNIFICANT EVENTS
The next UARS Yaw slew is scheduled for 17 October 2001 (DOY 290). This
maneuver will be a Forward to Reverse Flight maneuver (Northern 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 14 September 2001
ORBIT AOS NO. SUBSYS REASON
----- --- --- ------ ------
54660 252/2319 01-563 PEM Power OFF
54661 253/0022 01-564 HRDI Low Power
54675 253/2320 01-565 SUSIM Power OFF
54685 254/1458 01-566 OBC "Yaw start, TAM to monitor mode"
54686 254/1538 01-567 OBC "Yaw complete, TAM to update mode"
54722 257/0149 01-569 SOLSTICE DAY-ONLY MODE
54729 257/1250 01-570 SUSIM Power ON
54730 257/1430 01-571 SOLSTICE FULL-TIME MODE
54730 257/1430 01-571 OBC Clk Adj 0.00 to -20.6 msec/day
______________________________________________________________________________________
APPENDIX B
OUT-OF-LIMITS & ALERTS OCCURRENCES
Week ending 14 September 2001
The following Out-Of-Limits occurrences were detected:
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 14 September 2001
CLOCK DRIFT RATE ADJUSTMENTS
ORBIT TIME CLOCK RATE CHANGE
----- ----- -----------------
54730 257/1430 Clk Adj 0.00 to -20.6 msec/day
___________________________________________________________________________
APPENDIX D
UARS BATTERY PERFORMANCE DATA
Week ending 14 September 2001
7 September 2001 - GMT Day 250 Beta = 17.6 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 -3.05/-4.31 +0.0/+0.0 11.8 0.000 0.0
2 +11.2/-67.2 +6.44/+5.15 +29.6/-14.4 23.8 1.040 22.0
3 +22.4/-44.8 +5.15/+3.87 +28.8/-14.4 23.8 1.030 21.5
14 September 2001 - GMT Day 257 Beta = 10.1 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 11.8 0.000 0.0
2 +00.0/-78.4 +4.51/+3.87 +28.8/-13.6 26.1 1.030 19.2
3 +22.4/-16.8 +3.23/+2.60 +28.0/-13.2 25.8 1.030 18.8
V/T LEVEL CHANGES
ORB# TIME LVL FR-TO
----- ---- ---------
-no changes V/T 5
_______________________________________________________________________________
APPENDIX E
UARS ANOMALY REPORTS
Week ending 14 September 2001
NEW ANOMALY REPORTS GENERATED
AR NO. SUBSYS ORBIT TIME TTR PROBLEM/DATA LOSS
------ ------ ----- ---- --- -----------------
01-056 FOT 54671 253/1544 N/A Errors on Pack PE 44
ANOMALY CLOSURE INFORMATION RECEIVED
AR NO. SUBSYS ORBIT TIME TTR PROBLEM/DATA LOSS
------ ------ ----- ---- --- -----------------
01-056 FOT 54671 253/1544 N/A Errors on Pack PE 44
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
------ ------ ----- ---- --- -----------------
01-054 FOT see list Sept. 01 14170 Generic Late Acquisition
SEVNTFW01/37