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UARS WEEKLY STATUS REPORT - 01 MAY 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 resumed operations on April 20. Since then, SUSIM has
successfully gathered its normal solar, offset, and occultation scan
data without apparent problems. Additionally, SUSIM did its quarterly
and monthly lamp calibrations this past week.
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PEM
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The PEM zenith spectrometers were active between April 20 through April 24.
During this time, PEM computed energy deposition from in situ particles.
GSFC has proposed an OBC operation plan for the activation of PEM boom
instruments during the daylight portions of every orbit. This OBC operation
plan is under evaluation by PEM.
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HALOE
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HALOE was successfully operating when it was turned off at the scheduled
time, end of day April 28, 1998. All engineering parameters were nominal
and the science data results continue to be excellent.
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MLS
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MLS was reactivated successfully on Apr 29, in the reduced 85 watt power
mode. MLS instrument operations have continued flawlessly. MLS is scheduled to
operate through May 2.
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HRDI
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HRDI is currently on and operating normally. Scheduled turnoff is 4/30/98.
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WINDII
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WINDII is currently off, and scheduled to resume operations on
May 11.
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MPG
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When electric power was restored to the CDHF routers (after the
April 24-27 power outage) there was a 2-day delay in restarting
DECNET communication between four UARS instrument Remote Access
Computers (RACs) and the UARS Command Management System (CMS).
CMS software requires the use of DECNET to receive instrument
Daily Activity Plans. The MPG Remote Analysis Computer was used
to submit Daily Activity Plans for the instruments affected.
Routine processing of instrument Daily Activity Plans continues
with no other problems. The MPG continues to assist the Project
Scientist with the scheduling of instrument operations.
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CDHF
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CDHF personnel performed the facility power down and power up for the
building 23 power outage from 04/24/98 to 04/27/98. Users were alerted in
advance and network routers were powered down in accordance to predetermined
plan. No significant problems occurred during the power up. The cluster was up
and operational at approximately 13:00L.
The CDHF has received a total of 386 CD-ROM requests as of 1-May-1998.
There were no new orders received.
The CDHF received approval from MLS and has loaded all MLS V4.90, subtype
(ICE_SATURAT) LEVEL3AT files to the DAAC.
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.
20 days PEM (3.32) PROD (1379R-1169C=210L)
11 days CLAES (7.0) ENG (72R-71C-1F=0L)
264 days ATT (7.2) PROD (2178R-2178C=0L)
0 days HAL (4.80) PROD (Test) (2R-0C=2L)
1 days SOL (4.52) PROD (Test) (2R-1F-1C=0L)
The CDHF will load March 1998 current day DAAC data in May 1998.
Pending software upgrades: IDL 5.1, OpenIngres, UCSS.
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FOT
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REPORTING PERIOD
This report covers 17 April 1998 (Orbit 36064, GMT Day 107) through 24
April 1998 (Orbit 36168, GMT Day 114).
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
MLS 109/2245 36093 Off
ACRIM 110/0027 36094 On
WINDII 110/0644 36098 On
PEM 110/1053 36101 ZEPS on
SUSIM 110/1213 36101 On
WINDII 113/2301 36153 Off
PEM 114/2249 36168 ZEPS off
The beta angle reached a maximum angle of 45.7 degrees on 19 April 1998
(DOY 109). The beta angle is now decreasing toward a minimum angle of 0.0
degrees on 05 May 1998 (DOY 125).
Two manually generated SSPP Stellar Offset experiments requested by
SOLSTICE were performed on GMT Day 111 and 113.
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 25.0 V end-of-night (EON) load bus
voltage. Battery temperatures are stable with a temperature delta between
Battery 2 and Battery 3 of 1.0 degrees C. Additional battery performance
data for each battery on 18 April 1998 and 23 April 1998 are provided in
Appendix D.
The clock error ranged from -10.6 to +10.9 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 = 03
The following real-time command sheets were executed for the listed
operational element(s) during this report period (see Appendix A).
% FOT 04
% ACRIM 01
% HALOE 01
% MLS 01
% SUSIM 01
% PEM 02
% WINDII 02
UARS Anomaly Reports initiated during this report period are listed in
Appendix E and summarized below.
% FOT 03
One (1) Anomaly Reports remained OPEN at the end of this report period (see
Appendix E).
TRANSPONDER FREQUENCIES:
Transponder A: 98/062 - 2287.496945
Transponder B: 98/062 - 2287.497010
GROUND SYSTEM OPERATION
One (1) 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 98/113 show the observatory data loss to be
20 hours, 42 minutes, 54.164 seconds (an increase of 1.088 seconds since
last report period). This is a 0.0359 percent data loss which equals a
99.9641 percent data capture for the mission.
The increase of 1.088 seconds occurred on Day 113 due to insufficient
overlap.
The FOT DID NOT experience along track ephemeris transition comparisons in
excess of 1.5 km when processing the ephemeris in the Command Management
System (CMS) software. Apparently, the solar flux activity has
significantly reduced lately, resulting in more stable ephemeris
predictions. FDF is still investigating the possible need to transition to
more frequent spacecraft ephemeris deliveries (i.e. back to a daily
delivery schedule instead of the current Monday/Wednesday/Friday schedule).
No IP testing was performed by the UARS FOT this week.
The FOT continued making modifications to the OBCSTF resident POCC
database. There are an extensive number of database changes/additions that
are required to support the upcoming flight software/PMON update. The
modifications required for this release require full-time dedication to
database work. All of the current database modifications will be
incorporated into database version 67, not version 66 as previously stated.
Version 66 is an interim RtestS database release (to support a reduced ATC
load test) generated a few months previous.
Approximately 33 Relative Time Sequences (RTSs) and 8 Predefined Blocks
(PDBs) were created by the FOT on the Command Management System this week.
The purpose of the new RTSs/PDBs is to support the upcoming flight
software/PMON update. The RTSs and PDBs will be generated into spacecraft
loads on the CMS, at which time each load will be converted to a hex-format
dump. The resulting dumps will aid in building part of the new flight
software image.
The second Building 23 power outage began on schedule at noon on 24 April
1998. The outage will continue until 27 April 1998.
OTHER SIGNIFICANT EVENTS
Work on the upgrade of the OBC Power Monitor (PMON) continued. All of the
database inputs for new PMON software were completed this week.
Work continues on the UARS August orbit adjust planning. Data covering the
March 1995 safehold period were re-plotted and reviewed. The data shows
that the thrusters on both B and D Rocket Engine Modules (REM) were fired
while the latch valve controlling fuel to them were closed. The
spacecraft showed response of the correct polarity of spacecraft rates to
the firings at the beginning which dwindled to no response as the firings
continued. This leads to the conclusion that the hydrazine lines are
depleted to the both the B and D thruster valves. This is the same
conclusion reported in the original Safehold Anomaly Report.
FOT continues to support CNMOS in their efforts to make necessary software
changes (MSOCC, CMS, DCF, etc.) to support the year 2000 rollover.
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.
A meeting was held on 21 April 1998 between CNMOS and the FOT
representatives to discuss and confirm the changes made to the OBC Ground
Image to support the OBC Flight Software update (Version 63). This update
reduces the Absolute Time Command (ATC) size from 1024 commands to 768
commands and relocates some processor code. This reduction and code
relocation was made to provide an increase in the number of commands
available for allocation to Relative Time Sequences (RTSs). Discussions at
this meeting revealed a misunderstanding of the requirements regarding the
ATC area within the Application Processor (AP) software Ground Image. A
follow-on meeting was scheduled for 23 April 1998.
FOT attended a meeting with GSFC Propulsion Branch personnel (Dennis Asata
and Mike Rhee) on 22 April 1998. Data on the latch valve, thruster valves,
Hydrazine piping, and fuel pressure were provided by flight operations.
Following task authorization, they will run a preliminary worst case type
analysis to determine the magnitude of the refill problem. Analysis of the
results will determine whether a Latch Valve should be procured for ground
testing. If a ground test is required, the FOT was ask to check if the
UTTS could provide the commands to open the Latch Valve with the same
timing as will be used on the spacecraft. Results from the analysis and/or
ground test (if required) will be used to finalize the refill procedure.
A follow-up meeting to discuss and confirm the changes made to the OBC
Ground Image to support the OBC Flight Software update was held on 23 April
1998 with an expanded list of attendees to reach a decision as to the
correct approach for ground/spacecraft image alignment. The problem was
presented and discussed during the meeting. A decision was reached to
correct the ground image in a new version of the AP software. This effort
was estimated to be one week. The AP software update would take place
during the FOT data base population period and therefore would not
significantly impact the schedule. The already completed version of the AP
software (version 10.10) would be retained as a backup. A following-up
meeting was scheduled for 30 April 1998 to review the status of the effort.
FUTURE SIGNIFICANT EVENTS
The next UARS Yaw Around Maneuver is currently scheduled for 05 May 1998.
The UARS orbit altitude is dropping slowly and a drag makeup orbit adjust
is targeted for 05 August 1998.
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 24 April 1998
ORBIT AOS NO. SUBSYS REASON
----- --- --- ------ -------
36087 109/1354 98-137 OBC Clk Adj 20.6 to 0.00 msec/day
36093 109/2245 98-138 MLS Power OFF
36094 110/0027 98-139 ACRIM Power ON
36098 110/0644 98-140 WINDII Power ON
36101 110/1053 98-141 PEM Power ON ZEPS
36101 110/1213 98-142 SUSIM Power ON
36102 110/1354 98-143 OBC Re-loaded RTS-12 (HTR Cycle)
36111 111/0331 98-144 OBC Clk Adj 0.00 to 20.6 msec/day
36131 112/1223 98-145 HALOE Changed HALOE stow position.
36149 113/1622 98-146 OBC Clk Adj 20.6 to 0.00 msec/day
36153 113/2301 98-147 WINDII Power OFF
36168 114/2249 98-148 PEM ZEPS Turn Off
_______________________________________________________________
APPENDIX B
OUT-OF-LIMITS & ALERTS OCCURRENCES
Week ending 24 April 1998
MNEMONIC STATE DESCRIPTION ORBITS
--------- ----- ------------ ------
HRIFESURVTMP Y-HI IFE Survival Heater Temp 36159
QTSISAIF Y-HI SSPP Baseplate by SISA I/F continuous
QTSSPPMX Y-HI SSPP -X Thermostat 36073-78,86-89,99-103
The following ALERT occurrences were detected:
MNEMONIC DESCRIPTION ORBITS
--------- ------------ ------
None this report period
APPENDIX C
CLOCK & SOLAR ARRAY RATE CORRECTIONS
Week ending 24 April 1998
CLOCK DRIFT RATE ADJUSTMENTS
ORBIT TIME CLOCK RATE CHANGE
----- ---- -----------------
36087 109/13:58 (19 Apr 98) from 20.6 to 00.0 msec/day
36111 111/03:36 (21 Apr 98) from 00.0 to 20.6 msec/day
36149 113/16:26 (23 Apr 98) from 20.6 to 00.0 msec/day
_______________________________________________________________
APPENDIX D
UARS BATTERY PERFORMANCE DATA
Week ending 24 April 1998
18 Apr 1998 - GMT Day 108 Beta = 45.6 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/-4.05 +0.0/ +0.0 18.4 0.000 0.0
2 +56.0/ -11.2 +6.16/+5.15 +26.9/-15.8 25.1 1.022 22.5
3 +89.6/ -5.6 +5.15/+3.87 +26.0/-15.7 25.1 1.026 21.8
23 Apr 1998 - GMT Day 113 Beta = 41.4 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/-3.91 +0.0/ +0.0 18.4 0.000 0.0
2 +56.0/ -11.2 +6.44/+5.15 +27.9/-15.8 25.0 1.023 22.6
3 +112.0/ +0.0 +5.15/+3.95 +27.0/-16.0 25.0 1.026 22.0
V/T LEVEL CHANGES
ORB# TIME LVL FR-TO
----- -------- ----------
no changes
APPENDIX E
UARS ANOMALY REPORTS
Week ending 24 April 1998
NEW ANOMALY REPORTS GENERATED
AR NO. SUBSYS ORBIT TIME TTR PROBLEM/DATA LOSS
------ ------ ----- ---- --- -----------------
98-019 FOT 36086 109/1057Z N/A TAC #4 Crashed. No impact.
98-015 FOT 36099 110/0910 14170 Generic Late Acquisition
98-120 FOT 36120 111/1854 N/A TAC #6 Crashed
ANOMALY CLOSURE INFORMATION RECEIVED
AR NO. SUBSYS ORBIT TIME TTR PROBLEM/DATA LOSS
------ ------ ----- ---- --- -----------------
98-019 FOT 36086 109/10:57 TAC 4 CRASH
98-020 FOT 36120 111/18:52 TAC 6 CRASH
ANOMALY INVESTIGATION REPORTS GENERATED
AIR NO. SUBSYS ORBIT TIME TTR PROBLEM/DATA LOSS
------- ------ ----- ---- --- -----------------
None this report period
OPEN ANOMALY REPORTS
AR NO. SUBSYS ORBIT TIME TTR PROBLEM/DATA LOSS
------ ------ ----- ---- --- -----------------
98-015 Generic Late Acq for April 1998 (Open until 30 April 1998).