******************************************************************** 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