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UARS WEEKLY STATUS REPORT - 02 Oct 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 successfully gathered its normal solar, offset, and occulation
data during this past week without apparent problems.
We have asked that the version 7 SUSIM production software be promoted.
Reprocessing to the new version (V20) will soon begin.
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PEM
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PEM was not active
PEM is now conducting tests of the OBC activation. PEM activation
occurs during daylight only, when there is adequate power generated from
the UARS solar array. Currently, testing is half-way completed, and the
PEM magnetometer and medium energy spectrometers can activate under OBC
control. Tests are now being conducted on the high energy particle
spectrometers. Initial tests of these units show failure to enable high
voltage power. The PEM team is investigating this result.
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HALOE
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HALOE is presently off due to the yaw and is scheduled to power on
beginning of day October 3. When HALOE was on it was operating within its
nominal operating range. All science channels continue to provide excellent
science data.
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MLS
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MLS is scheduled to begin operations on Oct 6 and operate though Oct 10. The
MLS team will operate the instrument in a mode for diagnosing the reoccurance
of slips in the antenna scan mechanism, and to attempt to find a method of
operating the instrument which minimizes the impact of these slips on
scientific data.
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HRDI
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HRDI started operating in the daytime-only mode on September 30th. We are
currently evaluating operations in this new configuration.
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WINDII
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WINDII is currently off, and is planned to be activated
Oct. 5-11, 1998.
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MPG
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Routine processing of instrument Daily Activity Plans continues
with no problems. The MPG continues to assist the Project
Scientist with the scheduling of instrument operations.
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CDHF
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The CDHF attended a meeting involving possible impacts resulting
from the scheduled chilled water outage on the weekend of October 10-11.
Current plans do not include an interruption in service at the CDHF
during this time period.
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.
60 days HAL (4.80) PROD (L1) (1873R-1560C-23F=290L)
24 days HAL (4.80) PROD (L3) (1873R-882C=991L)
85 days SOL (4.62) PROD (L2-L3) (2349R-1686C=663L)
1 days SEN (5.00) PROD (L0) (1R-1C=0L)
The CDHF is scheduling the installation of IDL software version 5.1. This
installation will satisfy Y2K requirements and is also recommended by RSI as
a possible solution to a current PRINT routine problem reported by SOLSTICE.
The CDHF maintains a matrix of installation status on all patches/upgrades
required on the current UARS VMS cluster operating systems for Y2K compliance.
CDHF pending software upgrades: SUSIM v7.0, IDL 5.1, OpenIngres
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FOT
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REPORTING PERIOD
This report covers 19 September 1998 (Orbit 38370, GMT Day 262) through 25
September 1998 (Orbit 38474, GMT Day 268).
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 262/0708 38374 ZEPS Off
PEM 262/0943 38376 AXIS On
PEM 266/2129 38443 AXIS Off
WINDII 267/0401 38447 Off
HALOE 267/0921 38450 On
SOLSTICE 267/1102 38451 On
ACRIM 267/1102 38451 On
SUSIM 267/1950 38457 On
The beta angle ranged between 41.5 degrees to 17.1 degrees for this report
period. The beta angle is now decreasing toward a minimum angle of -2.0
degrees for the yaw on 29 September 1998 (DOY 272).
The new power monitor (PMON) flight software was successfully uplinked
during orbits 38446, 38447, 38448, and 38449 (267/02:21, 267/04:01,
267/05:46, and 267/06:38 UTC). PMON control of heaters began during orbit
28450 (267/07:34 UTC). The upgraded version of PMON includes enhanced
capabilities for Rday-onlyS heater control, used to minimize spacecraft
power loading during the solar array eclipse period (approximately half of
each orbit). The enhanced PMON software also includes the capability to
support Rday-onlyS operation of instruments, in which they will be power
cycled on when the solar array has excess power, and turned off during
array eclipse periods. PMON currently can support three instruments for
this mode of operation: PEM, HRDI, and SOLSTICE.
Following the first orbit of the PMON software uplink, a low load bus
voltage condition (23.2 V) resulted in automatic power shedding via the
telemetry monitor (TMON) flight software. The SSPP instruments (SOLSTICE,
ACRIM, and SUSIM), as well as the HALOE and WINDII instruments, were
powered off as part of this load shedding. The low bus voltage resulted
from the long duration of the first contact during solar array Rnight.S
Pre-uplink simulations also showed low bus voltage for this contact (23.4
V), but not low enough to RtripS TMON and result in the load shedding which
actually occurred. However, such fluctuations in bus voltage can result
from minor orbital changes in other spacecraft loads, and therefore are
tremendously difficult, if not impossible, to predict with certainty.
Regardless, the TMON response was proper under the circumstances, and the
SSPP and HALOE instruments were restored to full operation as soon as
possible (WINDII was scheduled to be turned off the following day, so it
was left powered off).
Examination of PMON telemetry following the uplink showed it working as
planned, with one exception. The WINDII heater load was not being properly
controlled, due to a power switching unit (PSU) command conflict. PSU
documentation indicates that PSU commands must be separated by at least one
second, and the PMON command responses were designed accordingly. However,
post-uplink examination of telemetry showed that the WINDII heater commands
(which followed other PSU commands from PMON by one second) did not
function. The FOT determined that one second separation of PSU commands
was probably not adequate, so the PMON command responses were modified to
ensure at least two seconds between each PSU command. These changes were
uplinked on orbit 38473 (268/21:30 UTC), and all PMON PSU commands have
functioned properly since that time.
Two manually generated SSPP stellar offset experiments were performed on
GMT days 265 and 267 at the request of SOLSTICE operations.
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 1.0 to 1.3 degrees C. Additional battery performance data
for each battery on 18 September 1998 and 25 September 1998 are provided in
Appendix D.
The clock error ranged from 10.2 to -11.7 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 = 00
% 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 06
% ACRIM 01
% HALOE 01
% PEM 03
% SOLSTICE 01
% SUSIM 01
% WINDII 01
UARS Anomaly Reports initiated during this report period are listed in
Appendix E and summarized below.
% FOT 04
Four (4) Anomaly Report remained OPEN at the end of this report period (see
Appendix E).
TRANSPONDER FREQUENCIES:
Transponder A: 98/210 - 2287.496941
Transponder B: 98/211 - 2287.499161
GROUND SYSTEM OPERATION
Two (2) 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 98/267 show the observatory data loss to be
21 hours, 06 minutes, 52.340 seconds (an increase of 11.200 seconds since
last report period). This is a 0.0344 percent data loss which equals a
99.9656 percent data capture for the mission.
The increase of 11.200 seconds occurred over two days:
7 0.256 seconds on Day 266 due insufficient overlap, and
7 10.944 seconds on Day 267 due to insufficient overlap.
The FOT created and configured a new CMS Spacecraft Characteristics and
Parameters file to accommodate the operational change to a reduced size ATC
memory. As of the PMON/Flight Software uplink on 24 September, the size of
the stored command memory is now 768 commands (as compared to the previous
size of 1024 commands). In addition, the FOT created several new Relative
Time Sequences(s) (RTSs) which were also necessary to facilitate proper
PMON commanding with the new flight software.
A final dry run simulation of the new Power Monitor Software was completed
on 23 September 1998.
The operational packs, software and database version following the PMON
software update are:
PACK # GND S/W VER DATBASE VER COMMENT
PE51 10.12 FOT 069 Prime
PE03 10.12 FOT 069 Backup
OTHER SIGNIFICANT EVENTS
UARS SATELLITE OPERATIONS
FOT continues to improve a power profile for UARS based on the current
status of the Modular Power System.
Investigation into possible impacts of the Leonid meteorite shower in
November 1998 continues. FDF has supplied Leonid flux angles to both UARS
Fixed Head Star Trackers (FHST).
YEAR 2000 OPERABILITY SUPPORT
UARS Test and Training Simulator (UTTS) - No change.
User Planning System (UPS) - The FOT coordinated with the UPS development
team lead to discuss the FOTUs and the CMS test teamUs TDRS contact needs
for Year 2K testing. Several options for getting a Year 2K TDRS contact
data to the CMS system were discussed. These options will be pursued early
next week.
Multi Satellite Operations Control Center (MSOCC) - Per an action item from
last weekUs POCC/AP Year 2K status meeting, the FOT researched several
questions given to them by the POCC/AP test team. The FOT is in the
process of generating a memorandum containing answers to the test teamUs
questions.
At the request of the POCC test team, the FOT attempted to generate a
sample Year 2K ATC load which included nothing but NOOP commands. The
purpose of the sample load was to enable the POCC/AP test team to perform
load acceptance testing on the AP. Unfortunately, the FOT and CMS test
team was unable to successfully generate such a load. Both the FOT and the
CMS test team are currently investigating the reason that the back-up CMS
is failing during the load generation process involving a Year 2K load.
Command Management System (CMS) - The FOT met with CMS software development
team representative Tony Yan to discuss possible Year 2K related problems
with the CMS software. Specifically, Year 2K testing found that the CMS
does not correctly sort the AOT and LOT of targets in the SSPP Orbital
Events file when the view period of the target crosses the 1999-to-2000
year boundary. However, this particular problem does not present an
operational concern as the only SSPP target that is viewed during that
portion of the day is the Sun, and the Sun is not actually in view of UARS
during the 1999/2000 cross-over.
Flight Dynamics Facility (FDF) - A partial coordinated data set was
received at the end of this week but no testing has been attempted.
OBC PMON FLIGHT SOFTWARE UPDATE
Flight Software - Complete.
Ground Support Software - Complete.
Verification Testing - Complete.
Uplink - Successfully completed on 24 September 1998.
IP NETWORK TESTING
Space Network (SN) - No change.
Testing with the NCC 98 system to support routine flight operations is
being planned.
Deep Space Network (DSN) and Ground Spaceflight Tracking and Data Network
(GSTDN) - Commanding with the JSC simulator (destination code problem) is
being investigated.
UARS PROPULSION MODULE B/D THRUSTER LINE FILL
The B/D thruster refill effort continues. The Eaton Latch Valve test
report is still being reviewed by the UARS FOT.
UARS RE-ENGINEERING - TELEMETRY PROCESSING
Flight operations is providing support to the re-engineering effort to
process the UARS telemetry on the TOMS/EP control center computer system.
The software performance continues to be evaluated.
UARS COMMAND RE-HOST PHASE 1 DEMONSTRATION
A phase 1 feasibility demonstration of the Lockheed Martin SCS-21 control
center system was successfully conducted on 22 September 1998. The NCC-98
system was not available for the demonstration. Future development is
waiting Rgo aheadS approval.
MEETINGS
The FOT attended a meeting on 24 September 1998 concerning the User
Planning System (UPS) Y2K release and plans for verification testing.
The next battery telecon is scheduled for 20 October 1998 at 1:00 pm.
FUTURE SIGNIFICANT EVENTS
The next UARS Yaw Around Maneuver is scheduled for scheduled for 29
September 1998.
The United States Naval Observatory (USNO) issued a Time Service
announcement advising that the International Earth Rotation Service (IERS)
will retard UTC time by 1.0 second at the end of December 1998. This means
the addition of one leap second as the last second of 1998.
The next annular solar eclipse will occur on 16 February 1999 over the
Indian Ocean, Australia and the South Pacific Ocean.
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 25 September 1998
ORBIT AOS NO. SUBSYS REASON
----- --- --- ------ -------
38374 262/0708 98-351 PEM ZEPS OFF
38376 262/0943 98-352 PEM AXIS ON
38402 264/0409 98-353 OBC Clk Adj fr 0.00 to 20.6 msec/day
38426 265/1755 98-354 OBC Clk Adj fr 20.6 to 0.00 msec/day
38443 266/2129 98-355 PEM Power Off AXIS
38447 267/0401 98-356 WINDII Power OFF
38448 267/0546 98-357 OBC Clear TMONS
38446 267/0221 98-358 OBC Load PMON Ver. 63
38450 267/0921 98-359 HALOE Power ON
38451 267/1102 98-360 SOLSTICE Power ON
38451 267/1102 98-361 ACRIM Power ON
38457 267/1950 98-362 SUSIM Power ON
38473 268/2130 98-363 OBC RTS Loads
38473 268/2130 98-364 OBC GENASCII - RTS
_______________________________________________________________
APPENDIX B
OUT-OF-LIMITS & ALERTS OCCURRENCES
Week ending 25 September 1998
MNEMONIC STATE DESCRIPTION ORBITS
--------- ----- ------------ ------
HRPSEQBIMON Y-HI PSE Quiet Bus Current Mon 38434,35,41,65,70
NBRECBI Y-HI NBTR-B Current 38434,35,70
QTSISAIF Y-HI SSPP Baseplate by SISA I/F 38446
OBSVLBEON R-LO Load Bus Volts at EON 38447-49
OBSBATVEON2 Y-LO Battery 2 voltage at EON 38447-49
OBSBATVEON3 Y-LO Battery 3 voltage at EON 38447-49
OBSSOC2 R-LO Battery 2 Current SOC 38448-9
OBSSOC3 R-LO Battery 3 Current SOC 38448-9
WIPBVOLTAGE Y-LO Pulse Bus Voltage 38434,35
WIQBVOLTAGE Y-LO Quiet Bus Voltage 38441
WIFWTEMP Y-LO Filter Wheel Temp 38457-465,473
WIISUTEMP R-LO ISU Temp 38453-73
The following ALERT occurrences were detected:
MNEMONIC DESCRIPTION ORBITS
--------- ------------ ------
WIISUTEMPRL ISU Temp Red Low 38455-8
WIFWTEMPRL Filter Temp Red Low 38456-7
WIISUTEMPRL WINDII ISU Temperature 38459-473
WIFWTEMPRL WINDII FW Temperature 38460,61,63
_______________________________________________________________
APPENDIX C
CLOCK & SOLAR ARRAY RATE CORRECTIONS
Week ending 25 September 1998
CLOCK DRIFT RATE ADJUSTMENTS
ORBIT TIME CLOCK RATE CHANGE
----- ---- -----------------
38402 264/04:15 (21 Sept 98) from 00.0 to 20.6 msec/day
38426 265/17:55 (22 Sept 98) from 20.6 to 00.0 msec/day
_______________________________________________________________
APPENDIX D
UARS BATTERY PERFORMANCE DATA
Week ending 25 September 1998
18 Sept 1998 - GMT Day 261 Beta = 41.5 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 -3.30/-2.73 +0.0/ +0.0 18.1 0.000 0.0
2 +67.2/ 0.0 +5.71/+6.44 +28.8/-16.0 24.6 1.022 22.5
3 +33.6/-22.4 +4.77/+5.47 +28.4/-16.8 24.6 1.023 22.1
25 Sept 1998 - GMT Day 268 Beta = 17.1 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 -3.05/-4.31 +0.0/ +0.0 18.1 0.000 0.0
2 +50.4/0.0 +6.76/+5.15 +31.6/-16.0 24.2 1.023 22.8
3 +33.6/-44.8 +5.47/+3.87 +30.4/-16.4 24.2 1.021 22.2
V/T LEVEL CHANGES
ORB# TIME LVL FR-TO
----- -------- ----------
no changes (V/T 5)
APPENDIX E
UARS ANOMALY REPORTS
Week ending 25 September 1998
NEW ANOMALY REPORTS GENERATED
AR NO. SUBSYS ORBIT TIME TTR PROBLEM/DATA LOSS
------ ------ ----- ---- --- -----------------
98-061 FOT 38385 263/0030 20202 AP-7 Crashed
98-057 FOT 38413 264/2123 14170 Generic Late Acquisition
98-062 TMON 38447 267/0401 N/A TMONs NR-1 & NR-2 TRIPPED
98-063 FOT 38456 267/1840 N/A ATC Load Errors
ANOMALY CLOSURE INFORMATION RECEIVED
AR NO. SUBSYS ORBIT TIME TTR PROBLEM/DATA LOSS
------ ------ ----- ---- --- -----------------
None this report period
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
------ ------ ----- ---- --- -----------------
98-057 FOT Sept 98 See list 14170 GENERIC LATE ACQ
98-061 FOT 38385 263/00:30 20202 AP CRASH
98-062 FOT 38447 266/04:01 TMON 1 & 2 TRIP
98-063 FOT 38456 267/18:43 ATC LOAD ERRORS