********************************************************************
UARS WEEKLY STATUS REPORT - 26 JUNE 1998
********************************************************************
***********
SOLSTICE
***********
SOLSTICE continues to operate normally, collecting solar data on all
available orbital tracking periods and stellar calibration observations,
whenever possible.
***********
SUSIM
***********
SUSIM has successfully gathered its normal solar, offset, and occultation
scan data this past week without apparent problems.
***********
PEM
***********
PEM/AXIS was active from June 18 through June 19 and became active again
on June 22. It is currently generating energy deposition from inverted X-ray
spectra for each of its 16 look directions.
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 accepted by PEM. PEM has proposed a series of test procedures for
activation and is waiting response from GSFC. PEM is also waiting for GSFC
scheduling and implementation of the OBC plan and its operation test procedures.
***********
HALOE
***********
HALOE was powered on June 20, 1998. All engineering parameters are nominal
and the science data products continue to be of excellent quality.
***********
MLS
***********
Nothing received.
***********
HRDI
***********
HRDI is currently off. Next scheduled turn-on is July 3rd.
***********
WINDII
***********
Nothing received.
***********
MPG
***********
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.
An orbit-adjust maneuver for the UARS spacecraft is being planned
for 12 August 1998. In preparation for the thruster firing on
12 August, small thruster "burns" for calibration are being
planned for 28 July 1998.
***********
CDHF
***********
Nothing received.
***********
FOT
***********
REPORTING PERIOD
This report covers 12 June 1998 (Orbit 36903, GMT Day 164) through 19 June
1998 (Orbit 37006, GMT Day 170).
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 169/0120 36978 AXIS on
PEM 170/2305 37006 AXIS off
The beta angle reached a minimum angle of 0.0 degrees on 15 June 1998 (DOY
166). The beta angle is now increasing toward a maximum angle of 33.8
degrees on 30 June 1998 (DOY 181).
A Forward-to-Reverse Yaw Around maneuver (number 69) was successfully
executed in Orbit 36941 at 13:56:57 UTC on 15 June 1998. The SSPP
Instruments (ACRIM, SOLSTICE, and SUSIM) were enabled. Due to the SA
position at 269 degrees, the effective night length of the spacecraft after
the maneuver was 48 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 23.5 and 23.0 percent respectively.
Two Rmanually generatedS stellar offset experiments requested by SOLSTICE
operations were performed on GMT days 167 and 169.
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 1.1 degrees C. Additional battery performance data for
each battery on 13 June 1998 and 19 June 1998 are provided in Appendix D.
The clock error ranged from -12.3 to -3.4 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 = 08
The following real-time command sheets were executed for the listed
operational element(s) during this report period (see Appendix A).
% FOT 01
% HRDI 05
% PEM 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: 98/146 - 2287.496748
Transponder B: 98/147 - 2287.499000
GROUND SYSTEM OPERATION
No (0) 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 98/162 show the observatory data loss to be
20 hours, 44 minutes, 05.940 seconds (an increase of 11.424 seconds since
last report period). This is a 0.0351 percent data loss which equals a
99.9649 percent data capture for the mission.
The increase of 11.424 seconds occurred on Day 167 and resulted from the
downlink Data Rate Change (DRC) not being covered by tape recorder data.
Command Management System (CMS) preparations to accommodate the upcoming
Flight Software/PMON uplink were implemented. This included verifying that
all CMS resident Relative Time Sequences (RTSs) are identical to the RTSs
in the flight software image, modifying CMS database files to reflect
planned changes in the size of the stored command loads as well as the size
allocation of individual RTSs, and testing of the aforementioned
modifications.
Testing the command side of the I/P Net remains on hold. Testing will
begin when MSOCC provides a command loop interface from the POCC through
the I/P Net to the UARS Simulator.
OTHER SIGNIFICANT EVENTS
Continued the upgrade to the OBC Power Monitor (PMON) flight software.
Ground System testing continued this week. Documentation of the System
table definitions was completed. New ASCII system table files were
generated. Extensive testing of the Ground Software was conducted on 17
June 1998. The ATSC programmer was present and the discrepancy related to
the DUMPCMD directive default values was demonstrated. This was thought to
be related to database version which was ruled out following tests with the
baseline, current operational, and revised (reduced ATC) versions.
Work continues on the UARS orbit adjust planning re-scheduled for 12 August
1998. An orbit adjust procedure using B/D thrusters for translation and
altitude control has been completed and is in review. A second orbit
adjust procedure using B/D thrusters for translation and A/C thrusters for
altitude control has also been prepared and is in review. The decision as
to which procedure is to be used will be made in early July and is
dependent on the latch valve refill tests scheduled by the propulsion
branch.
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
A meeting was held on 15 July 1998 with NASA and contractor personnel to
discuss the Propulsion Module Line Fill Test - Latch Valve drive circuits,
Remote Interface Unit (RIU), and the UARS simulator. A RIU from the Hubble
program will be available. Jackson and Tull personnel will build the drive
circuit and cabling based on schematics from the UARS spacecraft supplied
by the UARS FOT. Allied personnel will operate the UARS Test and Training
Simulator (UTTS) for the test. Arrangements have been made with the
Building 3 Facility Operations Manager (FOM) and ATSC Manager for a hallway
location to perform the test in Building 3 near the UTTS. The test is
planned for late July 1998.
No UARS Battery telecon was held this week. The next telecon has not been
scheduled.
FUTURE SIGNIFICANT EVENTS
The next UARS Yaw Around Maneuver is currently scheduled for 15 July 1998.
The UARS orbit altitude is dropping slowly and a drag makeup orbit adjust
is targeted for 12 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 19 June 1998
ORBIT AOS NO. SUBSYS REASON
----- --- --- ------ -------
36909 164/1114 98-196 OBC Clk Adj fr 20.6 to 0.00 msec/day
36945 166/2117 98-197 HRDI HTR Cycle from 175 to 25 amp mins
36953 167/1002 98-198 HRDI HTR Cycle from 25 to 100 amp mins
36970 168/1318 98-199 HRDI HTR Cycle from 100 to 75 amp mins
36978 169/0120 98-200 PEM AXIS Power ON
36987 169/1507 98-201 HRDI HTR Cycle 75 to 100 amp mins
36988 169/1656 98-202 HRDI HTR Cycle 100 to 125 amp mins
37006 170/2305 98-203 PEM/AXIS Power OFF
_______________________________________________________________
APPENDIX B
OUT-OF-LIMITS & ALERTS OCCURRENCES
Week ending 19 June 1998
MNEMONIC STATE DESCRIPTION ORBITS
--------- ----- ------------ ------
WIEUTEMP Y-LO WINDII EU Temperature CONTINUOUS
QTSISAIF Y-HI SSPP Baseplate by SISA I/F 36909-17,23-60,81-
84,89,93,96-8,701-2
HRPSEQBIMON Y-HI PSE Quiet Bus Cur. Monitor 36938,43-4,52,67,
81,82
SOSTMPRNTRN Y-LO Temperature Entrance 36932-47
ACTEMPANA2 Y-LO Temp ACR 2 36939-47
HRIFESURVTEMP Y-HI IFE Surv Temp 36959, 72-74,83
NBRECBI Y-HI NBTR B Current 36981-3,96
SOSTMPRBLFT Y-LO Temperature Bot_Left_Front 36943-44
The following ALERT occurrences were detected:
MNEMONIC DESCRIPTION ORBITS
--------- ------------ ------
None this report period
APPENDIX C
CLOCK & SOLAR ARRAY RATE CORRECTIONS
Week ending 19 June 1998
CLOCK DRIFT RATE ADJUSTMENTS
ORBIT TIME CLOCK RATE CHANGE
----- ---- -----------------
36909 164/11:17 (13 Jun 98) from 20.6 to 00.0 msec/day
_______________________________________________________________
APPENDIX D
UARS BATTERY PERFORMANCE DATA
Week ending 19 June 1998
13 Jun 1998 - GMT Day 164 Beta = 10.2 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/-4.62 +0.0/ +0.0 18.2 0.000 0.0
2 +44.8/ -11.2 +6.11/+3.87 +30.4/-13.6 25.8 1.020 21.3
3 +56.0/ -5.6 +4.83/+2.92 +29.2/-14.4 25.8 1.018 20.6
19 Jun 1998 - GMT Day 170 Beta = 11.6 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 18.2 0.000 0.0
2 +28.0/ -11.2 +5.79/+4.51 +31.2/-14.8 25.0 1.025 22.2
3 +84.0/ -5.6 +4.51/+3.55 +30.0/-15.2 25.0 1.022 21.6
V/T LEVEL CHANGES
ORB# TIME LVL FR-TO
----- -------- ----------
no changes
APPENDIX E
UARS ANOMALY REPORTS
Week ending 19 June 1998
NEW ANOMALY REPORTS GENERATED
AR NO. SUBSYS ORBIT TIME TTR PROBLEM/DATA LOSS
------ ------ ----- ---- --- -----------------
98-030 FOT 36910 164/1250Z N/A TAC #6 Crashed
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
------ ------ ----- ---- --- -----------------
98-024 FOT 36997 163/00:02 19991 LATE ACQ., NO RF
98-030 FOT 36910 164/12:50 TAC 6 CRASH
98-031 FOT 36930 165/19:55 TAC 6 CRASH
98-032 FOT 37973 168/16:51 TAC 4 CRASH
SEVNTFW25