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UARS WEEKLY STATUS REPORT - 1 Nov 2002
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We are extremely pleased to report that the UARS Team has apparently
won the 2002 William T. Pecora Award. This award is presented
annually to recognize outstanding contributions by individuals or
groups toward the understanding of the Earth by means of remote
sensing. The award is sponsored jointly by the Department of the
Interior and NASA. The award to the UARS Team is pending the
signatures of the Secretary of the Interior and the NASA
Administrator to be official.
Several of you provided endorsement letters in support of this
nomination. Thanks so much for your efforts!
The 2002 William T. Pecora Award will be presented at the
"Pecora 15 / Land Satellite Information IV Conference" at the
Adam's Mark Hotel in Denver, CO, during the keynote session
from 1:00-3:00 p.m. on Tuesday, November 12, 2002.
Carl (Skip) A. Reber, the original UARS Project Scientist,
will be accepting the award on the UARS Team's behalf.
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SOLSTICE
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Nothing received.
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SUSIM
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SUSIM resumed operations after the recent anomaly on Oct. 29.
Since then, SUSIM successfully performed its daily mid-resolution
and MgII solar scans 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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The PEM web site has moved. It has a new URL. Access the PEM web site
using http://wwwpem..space.swri.edu. The PEM data from the GUVI conjunction
periods has moved to http://wwwpem..space.swri.edu/guvi-pem.html.
PEM continues to work with the GUVI team on the diagnosis of data from
the first conjunction period. Analysis of the two conjunction passes showed
that the aurora as detected by GUVI was at higher latitude than UARS.
GUVI images from other times from the first conjunction period show spatial
regions that both GUVI and PEM sampled when aurora was present. Separation
is several minutes to 10's of minutes when both instruments saw aurora. A
presentation will be made at the November American Meteorological Society
meeting on PEM's view of the first conjunction period. The title is "April
18-24, 2002: PEM Observations of Atmospheric Energy Input and Ionization
Rates determined from Precipitating Charged Particles". PEM has seen no aurora
during the second conjunction period.
PEM continues to receive NMC data files from NOAA. No problems have
been encountered. NOAA has changed the binary structure of the NMC data and
PEM is now receiving two data streams, one in the original VAX format and the
other from their new binary format.
*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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WINDII has solved its commanding problems and is now able to operate
normally again. It was most recently activated on October 29, 2002 and
is expected to continue operations until November 14. The Canadian Space
Agency has also agreed to support WINDII operations for one further
year.
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MPG
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The MPG assisted the FOT during analysis of the UARS
spacecraft anomaly which started on October 22.
The MPG continues to serve as the point-of-contact for UARS
instrument operations to support re-engineering of the UARS
Mission Operations Concept to develop capabilities for the
Science Traceability Mission.
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 19 October 2002 (Orbit 60730, GMT Day 292) through
25 October 2002 (Orbit 60834, GMT Day 298).
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
PEM 294/1314 60768 ZEPS/HEPS TO FULLTIME OPS
PEM 294/1314 60768 POWER ON - AXIS 2
PEM 294/1830 60771 POWER OFF/ON AXIS 1 & 2
HALOE 295/0348 60777 POWER OFF
ALL 295/0419 60777 POWER OFF
The beta angle ranged between the angles of 35.4 degrees to 62.7
degrees for this report period. The beta angle is now increasing
towards a maximum angle of 71 degrees on 31 October 2002 (DOY 304).
On-Board Computer Safehold mode was entered at 295/0122 UTC on 21
October 2002 during a real-time contact. The cause of the problem is
not known at this time but is under investigation.
The OBC controls the High Gain Antenna (HGA) and without the computer,
HGA/TDRS operations ceased. UARS nominally operates with transmitter
A on continuously which is output through the upper omni antenna for
contingency situations. TDRS operations was shifted to this link -
UARS omni antenna to TDRS SSA. This mode of operations is restrictive
for UARS since the telemetry is engineering data (reduced scope and
sampling) at a 1 kbps rate instead of 32 kbps. The OBC dump
capability is reduced to 1 kbps instead of 32 kbps.
OBC precision pointing control was also lost and UARS was placed in
safehold mode using Earth Sensor Assembly-2 (ESA-2). UARS earth
sensor 1 has failed and earth sensor 2 is nominally powered off to
conserve its remaining useful life.
The primary focus of the recovery effort was focused on getting UARS
out of OBC safehold and back to precision pointing mode as soon as
possible. All scheduled passes had to be re-scheduled to OMNI passes
to allow maximum contact with UARS. Then all 16 memory banks were
dumped in sequential order to the ground so that an analysis could be
done to determine what might have initiated the OBC safehold. Due to
the contacts being OMNI SSA contacts the bank dumps were rather time
intensive.
The next course of action was to re-load the OBC with a known "good"
copy of the UARS hardware load image from the ground. Again, with the
contacts being OMNI SSA the going was slow, at best. The FOT made use
of the available HIGH POWER FORWARD feature of TDRS to keep from
having to reload a bank in the case of a dropped NASCOM block. After
each bank was loaded it was dumped and compared with what was loaded
to ascertain that it was exactly what was sent.
The OBC was brought out of safehold on Wednesday (Day 297) after
turning on all the processors one by one. No problems were
encountered during this phase of the recovery. Once the OBC was
running, the HGA tracking was reestablished, and 32 kbps Science
telemetry along with 32 kbps OBC dump telemetry was restored.
As soon as the attitude converges, all instruments will be turned on
as is outlined in the schedule for this flight direction. In the
meantime the FOT is pursuing a small problem with getting the UARS
clock within tolerance for precision science observations.
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 0.95 to 0.96 degrees C. Additional
battery performance data for each battery on 11 October and 18 October
2002 are provided in Appendix D.
The clock error ranged from -?.? to 10.1 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 = 31
PEM = 02
HALOE = 01
UARS Anomaly Reports initiated during this report period are listed in
Appendix E and summarized below.
FOT = 02
Four (4) Anomaly Report remained OPEN at the end of this report period
(see Appendix E).
GROUND SYSTEM OPERATION
Two (2) 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
The FOT has focused all of its energy this week on the recovery from
the OBC halt condition. The OBC Halt occurred at approximately
288/0123 during a regularly scheduled UARS contact. The cause of this
anomaly is still under investigation and a full Anomaly Investigation
Report (AIR) will be written. Earth Sensor 2 was brought online at
the next contact through an SSA OMNI TDRS event. The earth sensor
immediately took out the attitude error that has occurred since the
OBC halt (roughly 8 degrees on roll and yaw). With the earth sensor
powered on, UARS was in a stable condition and the recovery efforts
began.
The OBC was dumped, reloaded and dumped again over the course of the
next day and a half. Once the load was confirmed by the dumps, the
OBC was restarted on the 296/1409 event. All processors were brought
online by the end of the 296/1822 event. The HGA was put back into
tracking mode over the course of the next few passes and UARS had its
first HGA pass since the anomaly at 296/2209.
The next day was spent watching the UFLTR converge to an attitude
solution using FSS and TAM as inputs. After observing this
convergence the solution seemed to show higher residuals than those
previous to the anomaly. After further investigation it was found
that the flight software clock was not properly set. The FOT uses a
Raytheon written procedure to perform its clock correlation and this
procedure was found to have an error. All day Friday (DOY 298) was
spent trying to resolve the issue with clock correlation and no
solution was found. The investigation will continue next week. Once
this issue is resolved the UARS instruments will be able to be turned
on again.
MEETINGS
- The FOT attended several meetings throughout the week to discuss
the safehold recovery activities.
FUTURE SIGNIFICANT EVENTS
The next UARS Yaw slew is scheduled for 18 November 2002 (DOY 322).
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 25 October 2002
ORBIT AOS NO. SUBSYS REASON
----- --- --- ------ ------
60760 294/0036 02-364 OBC/CLK CLK ADJ FR 0.0 TO 20.6 MSEC/DAY
60768 294/1314 02-365 PEM ZEPS/HEPS TO FULLTIME OPS
60768 294/1314 02-366 PEM POWER ON - AXIS 2
60771 294/1830 02-366 PEM POWER OFF/ON AXIS 1&2
60776 295/0256 02-367 MACS EARTH SENSOR 2 ON
60777 295/0348 02-368 OBC HARDWARE BANK DUMPS
60777 295/0348 02-369 HALOE POWER OFF
60777 295/0419 02-370 CADH CDH RECONFIG FOR 1K DUMP THRU OMNI
60777 295/0419 02-371 INST MANUALLY TURN INST.OFF
60783 295/1400 02-372 OBC LOAD BANK 0
60783 295/1458 02-373 OBC LOAD BANK 1
60784 295/1547 02-374 OBC LOAD BANK 15
60785 295/1631 02-375 OBC LOAD BANK 14
60785 295/1730 02-376 OBC BANK 14 DUMP
60790 296/0122 02-383 OBC LOAD BANK 6
60791 296/0200 02-384 OBC DUMP BANK 6; LOAD & DUMP BANK7
60791 296/0301 02-385 OBC LOAD BANK 8
60792 296/0347 02-386 OBC DUMP BANK 8, LOAD & DUMP BANK9
60792 296/0441 02-387 OBC LOAD BANK 10
60793 296/0529 02-388 OBC DUMP BANK 10, LOAD & DUMP BANK11
60794 296/0716 02-389 OBC LOAD & DUMP BANK 12
60794 296/0803 02-390 OBC LOAD & DUMP BANK 13
60795 296/0915 02-391 OBC LOAD & DUMP BANK 14
60795 296/0953 02-392 OBC LOAD BANK 15
60805 297/0107 02-399 OBC DISA. MUB FOR HALOE,SUSIM,WINDII
60813 297/1418 02-400 OBC TABLE 50 LOAD
60814 297/1455 02-401 OBC MODE 3
60814 297/1601 02-402 OBC SET GYRO BIAS
60815 297/1650 02-403 OBC ENA FSS/TAM
60815 297/1742 02-404 OBC TAM ALIGN
60816 297/1826 02-404 OBC GYRO BIAS
60816 297/1925 02-404 OBC GYRO BIAS
60817 297/2007 02-404 OBC GYRO BIAS
60820 298/0107 02-405 OBC GYRO BIAS RESET
60821 298/0255 02-405 OBC GYRO BIAS RESET
60827 298/1229 02-406 OBC ICAL TO 3 (OPS)
60828 298/1417 02-407 OBC CLOCK JUMP CMDS
60829 298/1454 02-408 OBC FSW CLOCK CMDS
60829 298/1559 02-407 OBC CLOCK JUMP CMDS
60831 298/1923 02-405 OBC GYRO BIAS RESET
60832 298/2005 02-409 OBC CLOCK JUMP CMDS
APPENDIX B
OUT-OF-LIMITS & ALERTS OCCURRENCES
Week ending 25 October 2002
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 25 October 2002
CLOCK DRIFT RATE ADJUSTMENTS
ORBIT TIME CLOCK RATE CHANGE
----- ----- -----------------
60760 294/0059 CLK ADJ FR 0.0 TO 20.6 MSEC/DAY
APPENDIX D
UARS BATTERY PERFORMANCE DATA
Week ending 25 October 2002
18 October 2002 - GMT Day 291 Beta = 34.9 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 -151.2/-173.6 -3.68/-4.63 +00.0/+00.0 08.3 0.000 0.0
2 +11.2/-72.8 +4.82/+3.87 +27.2/-14.4 25.6 1.020 19.8
3 +22.4/-22.4 +3.87/+2.91 +26.8/-14.4 25.4 1.020 19.2
25 October 2002 - GMT Day 298 Beta = 62.7 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 -145.6/-168.0 -2.42/-3.68 +00.0/+00.0 08.3 0.000 0.0
2 +00.0/-33.6 +3.55/+2.60 +20.8/-14.4 27.0 1.050 14.9
3 +22.4/-28.0 +2.60/+1.65 +20.0/-14.4 27.0 1.040 14.7
V/T LEVEL CHANGES
ORB# AOS TIME LVL FR-TO
----- -------- ---------
- None this report period
APPENDIX E
UARS ANOMALY REPORTS
Week ending 25 October 2002
NEW ANOMALY REPORTS GENERATED
AR NO. SUBSYS ORBIT TIME CDS PROBLEM/DATA LOSS
------ ------ ----- ---- --- -----------------
02-056 FOT 60775 295/0122 OBC CRASH
02-053 FOT 60775 297/1309 30832 GENERIC LATE ACQUISITION
ANOMALY CLOSURE INFORMATION RECEIVED
AR NO. SUBSYS ORBIT TIME CDS PROBLEM/DATA LOSS
------ ------ ----- ---- --- -----------------
-None this report period.
ANOMALY INVESTIGATION REPORTS GENERATED
AR NO. SUBSYS ORBIT TIME CDS PROBLEM/DATA LOSS
------ ------ ----- ---- --- -----------------
-None this report period.
OPEN ANOMALY REPORTS
AR NO. SUBSYS ORBIT TIME CDS PROBLEM/DATA LOSS
------ ------ ----- ---- --- -----------------
02-052 SOLSTICE 60366 267/1951 N/A LOADING PROBLEM
02-053 FOT 60630 285/1008 30382 GENERIC LATE ACQUISITION
02-054 FOT 60689 289/0819 31607 FORWARD FAIL-OVER AT WHITESAND
20 SEC RTD lost, non-recover
02-056 FOT 60775 295/0122 OBC CRASH