******************************************************************** UARS WEEKLY STATUS REPORT - 08 JAN 1999 ******************************************************************** *********** SOLSTICE *********** SOLSTICE continues to operate normally, collecting solar data on all available orbital tracking periods and stellar calibration observations, whenever possible. The CDHF has completed SOLSTICE version 10 re-processing and is now running the current processing stream only. *********** SUSIM *********** Nothing received. *********** PEM *********** PEM is now under PMON control! OBC activation tests of the high energy particle spectrometer (HEPS -- particles greater than 30 keV) were declared successful on UARS day 2670 (January 2, 1999). Beginning this date, all PEM activations should yield correct scientific data; however, data generated from the HEPS subsystem between December 17, 1998 and January 1, 1999 should be considered invalid and not used. The PEM team would like to thank the FOT, and in particular Peter Thomas, for their work and efforts related to obtaining a correct OBC activation procedure for the HEPS subsystem. *********** HALOE *********** HALOE was powered off on January 6th for the upcoming yaw after successfully operating since December 17, 1998. All engineering parameters were nominal and the science data products continue to be of excellent quality. *********** MLS *********** The instrument is now off as scheduled. *********** HRDI *********** Nothing received. *********** WINDII *********** Nothing received. *********** MPG *********** 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. *********** CDHF *********** Nothing received. *********** FOT *********** REPORTING PERIOD This report covers 26 December 1998 (Orbit 39838, GMT Day 360) through 01 January 1999. The observatory is now in Forward Flight (Southern Hemisphere viewing) with a +0.5 degree Roll (cold side down) and is performing nominally under two- battery operations. The instrument operational changes were: INSTRUMENT OPERATIONAL CHANGES Instrument Time Orbit Comment MLS 363/2312 39896 Off ACRIM 363/2312 39896 On SUSIM 364/0015 39897 On PEM 365/1626 39922 Testing A summary of Instrument operations supplied by the Mission Planning Group for the month December 1998 is contained in Appendix F, UARS Instrument Operations Summary. The beta angle ranged between 32.2 degrees to 29.9 degrees for this report period. The beta angle is now increasing toward a minimum angle of +1.0 degrees on 11 January 1999 (DOY 011). UARS Flight Software Time was adjusted consistent with the United States Naval Observatory (USNO) 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 meant the addition of one leap second as the last second of 1998. The PEM Instrument automated turn-on procedure for Day-Only Operation has been completed and successfully tested in orbit. HEPS-1 and HEPS-2 are working (HEPS-3 will not be operated day only). 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 25 December 1998 and 01 January 1999 are provided in Appendix D. The clock error ranged from 10.3 to -11.4 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 = 05 % OUT-OF-LIMITS = 02 The following real-time command sheets were executed for the listed operational element(s) during this report period (see Appendix A). % FOT 05 % ACRIM 01 % MLS 03 % PEM 09 % SOLSTICE 03 % SUSIM 01 UARS Anomaly Reports initiated during this report period are listed in Appendix E and summarized below. % FOT 01 Three (3) Anomaly Report remained OPEN at the end of this report period (see Appendix E). TRANSPONDER FREQUENCIES: Transponder A: 98/286 - 2287.496936 Transponder B: 98/300 - 2287.498964 GROUND SYSTEM OPERATION One (1) 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 98/365 show the observatory data loss to be 21 hours, 40 minutes, 58.964 seconds (an increase of 30.432 seconds since last report period). This is a 0.0340 percent data loss which equals a 99.9660 percent data capture for the mission. The increase of 30.432 seconds occurred over two (2) days: 7 0.512 seconds on Day 362 due to data hit; and 7 29.920 seconds on Day 365 due to data hit, year change, leap second adjust. OTHER SIGNIFICANT EVENTS UARS SATELLITE OPERATIONS The SSPP temperature stability is being analyzed. It appears that since SOLSTICE is cycling, the usual amount of heat is not being generated and along with the other SSPP instruments, getting slightly colder. Investigation revealed a problem in operation of Compensation Heater 18B. Operational changes were implemented but sufficient operational time to evaluate the thermal effect has not elapsed. The FOT is investigating the feasibility of a new PMON action to change battery V/T curves based on loading to mitigate battery risks in sun pointing safehold. YEAR 2000 OPERABILITY SUPPORT - No change UARS PROPULSION MODULE B/D THRUSTER LINE FILL Planning continues for the simulator testing. UARS RE-ENGINEERING - TELEMETRY PROCESSING - No change MEETINGS None FUTURE SIGNIFICANT EVENTS The next UARS Yaw Around Maneuver is scheduled for scheduled for 11 January 1999. 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 F, UARS Instrument Operations Summary APPENDIX A REAL-TIME COMMAND SHEETS Week ending 01 January 1999 ORBIT AOS NO. SUBSYS REASON ----- --- --- ------ ------- 39846 360/1416 98-516 MLS Scan Act OFF 39851 360/2251 98-517 MLS Scan Act ON 39872 362/0740 98-518 OBC Clk Adj fr 0.00 to 20.6 msec/day 39878 362/1757 98-519 PSU Enabled Comp Htr 18 A&B sides 39895 363/2039 98-520 SOLSTICE SOLSTICE RTSs 39896 363/2312 98-521 MLS Power OFF 39896 363/2312 98-522 ACRIM Power ON 39897 364/0015 98-523 SUSIM Power ON 39900 364/0420 98-524 OBC Clk Adj fr 20.6 to 0.00 msec/day 39900 364/0518 98-525 PSU Comp HTR 18 ON BOTH 39901 364/0707 98-526 SOLSTICE SOLSTICE RESET 39903 364/0932 98-526 SOLSTICE SOLSTICE RESET 39907 364/1550 98-537 PSU Comp HTR 18 ON BOTH 39921 365/1403 98-528 PEM Revised DAY-ONLY sequences 39922 365/1626 98-529 PEM DAY-ONLY TEST-1 39923 365/1735 98-530 PEM DAY-ONLY TEST-2 39924 365/1949 98-531 PEM DAY-ONLY TEST-3 39925 365/2126 98-532 PEM DAY-ONLY TEST-4 39927 001/0025 99-001 PEM PMON/PEM Test 6 39928 001/0206 99-002 PEM PMON/PEM Test 7 39929 001/0346 99-003 PEM PMON/PEM Test 8 39930 001/0528 99-004 PEM PMON/PEM Test 9 _______________________________________________________________ APPENDIX B OUT-OF-LIMITS & ALERTS OCCURRENCES Week ending 01 January 1999 MNEMONIC STATE DESCRIPTION ORBITS --------- ----- ------------ ------ QTSISAIF Y-LO SSPP Baseplate by SISA I/F 39845-912 QTACRIMIF Y-LO SSPP Temp at ACRIM I/F 39845-96 The following ALERT occurrences were detected: MNEMONIC DESCRIPTION ORBITS --------- ------------ ------ ACTEMPHMREDL ACRIM RED LOW 39897-8 ACTEMANA1RDL ACRIM RED LOW 39897-8, 900 ACTEMANA2RDL ACRIM RED LOW 39897-8 SOPUPERSTATA SOLSTICE DETECTORS OFF 39900 SOPUPERSTATA MODE SELECTED= "TWO" RED 39903 _______________________________________________________________ APPENDIX C CLOCK & SOLAR ARRAY RATE CORRECTIONS Week ending 01 January 1999 CLOCK DRIFT RATE ADJUSTMENTS ORBIT TIME CLOCK RATE CHANGE ----- ---- ----------------- 39872 362/07:47 (28 Dec 98) from 00.0 to 20.6 msec/day 39900 364/04:23 (30 Dec 98) from 20.6 to 00.0 msec/day _______________________________________________________________ APPENDIX D UARS BATTERY PERFORMANCE DATA Week ending 01 January 1999 25 Dec 1998 - GMT Day 359 Beta = 32.2 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 +61.6/+39.2 -2.73/-3.99 +0.0/ +0.0 16.8 0.000 0.0 2 +11.2/-67.2 +6.11/+5.15 +30.4/-15.2 25.3 1.028 21.8 3 +134.4/11.2 +5.15/+3.87 +30.0/-16.4 25.1 1.024 21.7 01 Jan 1999 - GMT Day 001 Beta = 29.9 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 +56.0/+33.6 -2.73/-3.99 +0.0/ +0.0 16.8 0.000 0.0 2 +33.6/-22.4 +6.44/+5.15 +31.2/-15.2 25.1 1.026 21.8 3 +44.8/-5.6 +5.15/+3.87 +30.4/-16.0 25.1 1.025 21.6 V/T LEVEL CHANGES ORB# TIME LVL FR-TO ----- -------- ---------- no changes V/T 5 APPENDIX E UARS ANOMALY REPORTS Week ending 01 January 1999 NEW ANOMALY REPORTS GENERATED AR NO. SUBSYS ORBIT TIME TTR PROBLEM/DATA LOSS ------ ------ ----- ---- --- ----------------- 98-124 FOT 39878 362/1757 20485 No ODM/GCMR capability 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 ------ ------ ----- ---- --- ----------------- 98-117 FOT Dec 98 353/07:02 14170 Generic Late Acq 98-123 FOT 39788 356/17:45 AP/ODN PROBLEM 98-124 FOT 39878 362/18:00 20485 N0 ODM/GCMR _______________________________________________________________ APPENDIX F UARS INSTRUMENT OPERATIONS SUMMARY Week ending 01 January 1999 INSTRUMENT SUMMARY FOR MONTH OF DECEMBER 1998 (hours) UNPLANNED UNSCHEDULED ON Day- OFF OFF OFF Only (Insufficient (Other Instrument (Actual) Ops (Scheduled) Power) Problem) COMMENTS ---------- ------ --- ----------- ----------- ----------- -------------- ACRIM 599 145 0 0 HALOE 575 169 0 0 HRDI 216 528 0 0 0 MLS 141 603 0 0 PEM (axis) 142 0 602 0 0 PEM (zeps) 4 715 25 0 0 PEM (heps) 4 0 740 0 0 See Note 1 SOLSTICE 600 144 0 0 0 SUSIM 597 147 0 0 WINDII 235 509 0 0 Note 1. PEM High Energetic Particle System (HEPS) was OFF while developing and testing automated turn-on procedure. The automated procedure will operate while the spacecraft is in daylight and has power available from the solar array. (When spacecraft is in darkness, operation of instruments and spacecraft systems rely on power from batteries. Only two of the three spacecraft batteries are currently operational. Battery power is not sufficient to operate all instruments simultaneously when spacecraft is in darkness.). Cold side of spacecraft was facing northward: 12.5 days Cold side of spacecraft was facing southward: 18.5 days SEVNTFW99/01