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UARS WEEKLY STATUS REPORT - 06 MAY 2005
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SOLSTICE
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SOLSTICE continues daylight only operations in support of the yaw
maneuver and low power availability. Otherwise, the instrument is in
good health gathering solar data on all available orbital tracking
periods. On average, we received 62% of each day's data amounting to
about 316 minutes of solar observing time per day.
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SUSIM
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SUSIM was turned off on April 16 and remains off.
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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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Nothing received.
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MPG
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The MPG continues to serve as the point-of-contact for UARS
instrument operations in support of the Science Traceability
Mission of UARS.
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 23 April 2005 (Orbit 74519, GMT Day 113) through
29 April 2005 (Orbit 74624, GMT Day 119).
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
SOLSTICE 113/0157 74520 POWER OFF
SOLSTICE 114/2304 74549 POWER ON TO DAY ONLY
HALOE 114/2304 74549 POWER OFF
HRDI 115/1319 74558 HEATERS DISABLED
A Forward-to-Reverse Yaw Around maneuver (number 139) was successfully
executed in Orbit 7619 beginning 119/ 15:03:38Z and completing at 119/
15:40:48Z on 29 April 2005. All instruments were in their off or
standby mode (except for SOLSTICE in day-only). Due to the SA
position at 284 degrees, the effective night length of the spacecraft
after the maneuver was approximately 49.70 minutes. Post maneuver
analysis of data indicate that during the Yaw Around, the end-of-night
load bus voltage was 26.40 volts and the average depths of discharge
(DODs) on Batteries 2 and 3 were approximately 20.16 and 10.25 percent
respectively. The next (reverse-to-forward) YAW is scheduled for 30
May 2005 (DOY 150).
The beta angle ranged between the angles of 22.6 degrees to 01.6
degrees for this report period. The beta angle is now increasing
towards a maximum angle of 38 degrees on 14 May 2005 (DOY 134).
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 23.6 V end-of-night (EON) load bus
voltage. Battery temperatures are stable with a temperature delta
between Battery 2 and Battery 3 of 5.14 to 4.77 degrees C. Additional
battery performance data for each battery on 22 April 2005 and 29
April 2005 are provided in Appendix D.
The clock error ranged from 10.6 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.
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 = 09
HALOE = 01
HRDI = 01
SOLSTICE = 03
UARS Anomaly Reports initiated during this report period are listed in
Appendix E and summarized below.
FOT = 06
Three (3) Anomaly Reports remained OPEN at the end of this report
period (see Appendix E).
GROUND SYSTEM OPERATION
Three (3) operational support problems occurred this period. Anomaly
Reports are included in Appendix E.
The data loss calculations are no longer being supplied by Data
Capture Facility (DCF).
OTHER SIGNIFICANT EVENTS
UARS SATELLITE OPERATIONS
This week the FOT continued to closely monitor the status of the
batteries. The batteries maintained their VT-5 charge level and were
able to support the HALOE fulltime and SOLSTICE day-only operations
prior to the yaw. This was almost the full operational load scheduled
with only SUSIM not powered on. The day prior to the yaw maneuver the
battery C/D ratios began to fall to 1.00-1.02, so VT-6 was commanded.
UARS then flew through the yaw with no power problems and maintained
it VT-6 configuration into the weekend. Next week the FOT will
consult with the NASA power branch to determine the best time to go
back to VT-5.
Also this week, the FOT continued its testing of the solar array
drive. On Monday the B drive continued its success of Friday and ran
up and down the safe-zone at the orbital rate, which was very
promising. The array then showed some small signs of pausing or
sticking on the last slew of the day. During Wednesday's testing the
B-drive stalled again and the testing of the A drive continued.
Although the promise of Monday diminished during the week, this
clearly showed that if the A drive can be neutralized the B-side runs
very well. The testing will continue with the goal of finding a way
to again neutralize the A-side.
MEETINGS
-None this report period
FUTURE SIGNIFICANT EVENTS
The next UARS Yaw slew is scheduled for 29 May 2005 (DOY 149). This
maneuver will be a Reverse to Forward Flight maneuver (Southern
Hemisphere viewing).
Attachments: Appendix A, Real-time Command 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 29 April 2005
ORBIT AOS NO. SUBSYS REASON
----- --- --- ------ ------
74520 113/0053 05-143 SOLSTICE REBOOT
74520 113/0157 05-144 SOLSTICE POWER OFF
74549 114/2304 05-147 SOLSTICE POWER ON TO DAY ONLY
74549 114/2304 05-146 HALOE POWER OFF
74554 115/0734 05-148 OBC/CLK CLK ADJ FR -20.6 TO 0.0 MSEC/DAY
74558 115/1319 05-149 HRDI HEATERS DISABLED
74561 115/1822 05-150 SADDE SADDE TESTING
74561 115/1925 05-151 TMON TMON GROUP #49 DISABLED
74573 116/1351 05-152 SADDE SADDE TESTING
74591 117/1815 05-153 SADDE SADDE TESTING
74603 118/1346 05-154 MPS VT L-5 TO VT L-6
74607 118/1922 05-155 SADDE SADDE TESTING
74608 118/2145 05-156 OBC/CLK CLK ADJ FR 0.0 TO -20.6 MSEC/DAY
74618 119/1343 05-157 MACS YAW - FWD TO REV
APPENDIX B
OUT-OF-LIMITS & ALERTS OCCURRENCES
Week ending 29 April 2005
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 29 April 2005
CLOCK DRIFT RATE ADJUSTMENTS
ORBIT TIME CLOCK RATE CHANGE
----- ----- -----------------
74554 115/0734 CLK ADJ FR -20.6 TO 0.0 MSEC/DAY
74608 118/2145 CLK ADJ FR 0.0 TO -20.6 MSEC/DAY
APPENDIX D
UARS BATTERY PERFORMANCE DATA
Week ending 29 April 2005
22 April 2005 - GMT Day 112 Beta = 26.0 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 -112.0/-156.8 -3.68/-4.94 +00.0/+00.0 05.9 0.00 0.0
2 291.2/ -28.0 +7.08/+5.79 +31.6/-20.0 25.3 1.03 22.95
3 257.6/-700.0 +2.60/+1.97 +20.8/-12.0 25.1 1.04 14.10
29 April 2005 - GMT Day 119 Beta = 01.6 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 -50.4/-078.4 -3.68/-4.94 +00.0/+00.0 06.1 0.00 0.0
2 -67.2/-112.0 +7.74/+6.11 +33.6/-18.0 26.4 1.03 22.72
3 235.2/-700.0 +2.60/+1.34 +18.8/-10.4 26.2 1.06 11.07
V/T LEVEL CHANGES
ORB# AOS TIME LVL FR-TO
----- -------- ---------
74603 118/1346 LV5 -> LV6
APPENDIX E
UARS ANOMALY REPORTS
Week ending 29 April 2005
NEW ANOMALY REPORTS GENERATED
AR NO. SUBSYS ORBIT TIME CDS PROBLEM/DATA LOSS
------ ------ ----- ---- --- -----------------
05-026 SOLSTICE 74520 113/0053 N/A SOLS TEMP LIMITS
05-023 FOT 74546 114/1928 30832 Generic Late Acquisition
05-027 FOT 74548 114/2224 39337 Data Drop Out
05-023 FOT 74553 115/0544 30832 Generic Late Acquisition
05-023 FOT 74568 116/0542 30832 Generic Late Acquisition
05-023 FOT 74589 117/1603 30832 Generic Late Acquisition
ANOMALY CLOSURE INFORMATION RECEIVED
AR NO. SUBSYS ORBIT TIME CDS PROBLEM/DATA LOSS
------ ------ ----- ---- --- -----------------
05-025 FOT 74518 112/2157 39315 Intermittent Dropouts
ANOMALY INVESTIGATION REPORTS GENERATED
AIR NO. SUBSYS ORBIT TIME CDS PROBLEM/DATA LOSS
------ ------ ----- ---- --- -----------------
-None this report period.
OPEN ANOMALY REPORTS
AR NO. SUBSYS ORBIT TIME CDS PROBLEM/DATA LOSS
------ ------ ----- ---- --- -----------------
05-023 FOT See List Apr 05 30832 Generic Late Acquisition
05-026 SOLSTICE 74520 113/0053 N/A SOLS TEMP LIMITS
05-027 FOT 74548 114/2224 39337 Data Drop Out