STEREO Weekly Meeting Minutes for 2014-06-03 (Week 23) ANNOUNCEMENTS ------------- * See the discussion below about solar conjunction operations. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * All subsystems on both spacecraft are nominal. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 22 (May 26-Jun 1) * On day 147 (May 27), during the DSS-55 support for Ahead, turbo decoder lock was lost intermittently beginning at 1111z through 1316z. This anomaly resulted in the loss of ten frames of SSR data. * On day 148 (May 28), the Data Handling (1.1.6) and Power (1.0.3) parameter releases were loaded to EEPROM on Ahead. * On day 150 (May 30), the G&C hga_stoplo parameter on Ahead was updated to 0.141372 radians (8.1 degrees) in RAM. This update prevents the HGA from continuing on through lower pointing angles to limit the HGA feed temperature at an acceptable level. The same parameter on Behind was set to 6.8 degrees. * On day 151 (May 31), during the DSS-45 support for Behind, turbo decoder lock was lost intermittently beginning at 2257z through 2308z due to heavy rain. This anomaly resulted in the loss of 6994 frames of SSR data. See DR #C110260 more information. * The average daily SSR playback volume during the week was 4.4 gigabits for Ahead, and 4.3 gigabits for Behind. Week 23 (Jun 2-8) * Momentum dumps are scheduled for both spacecraft on Tuesday, Jun 3. The 68th dump on Ahead is scheduled to start at 17:30 UT, and the 63rd dump on Behind is scheduled for 23:00 UT. * The target momentum for the Ahead momentum dump is lower than usual, 9 N-m-s instead of 15 N-m-s. This is due to the LGA calibration test coming up on Saturday. * On Saturday, Jun 7, there will be an LGA calibration test on Ahead using D14. This will involve rolling the spacecraft about the Sun line at a rate of 5 degrees per minute, which is the same as during the actual conjunction. There will be two rolls, each of 72 minutes duration. There will be no thruster firings during this test. A more detailed weekly schedule will be released after a few changes are made. * On Thursday, Jun 5, G&C software version 1.3 will be written to EEPROM copies 1 and 2 on Ahead. * Ahead has 12 passes during the week, and overall coverage is nominal. 70 meter passes, all at 720 kbps, are scheduled for Monday, Jun 2 (D63), Thursday, Jun 5 (D14), Friday, Jun 6 (D14), Saturday, Jun 7 (D14), and Sunday, Jun 8 (D63). The station 45 pass on Thursday, Jun 5, will be carried out at 160 kbps. The following station 26 passes will be carried out at 240 kbps: Monday, Jun 2, and Sunday, Jun 8. * Behind has 10 passes during the week, and overall coverage is nominal. 70 meter passes are scheduled for Wednesday, Jun 4 (D63 at 720 kbsp), and Friday, Jun 6 (D14 at 720 kbps). The following passes will be carried out at 160 kbps: Monday, Jun 2 (D25), Tuesday, Jun 3 (D15), Friday, Jun 6 (D55), Saturday, Jun 7 (D55), and Sunday, Jun 8 (D55). The station 26 pass on Saturday, Jun 7, will be carried out at 240 kbps. * The X-band on DSS 45 is still red. This will result in the loss of 2 dB. Week 24 (Jun 9-15) * On Tuesday, Jun 10, and Thursday, Jun 12, there will be downloads of MOps macros and fault protection releases to EEPROM on both spacecraft in preparation for solar conjunction. * A test of the HGA side lobes on Ahead will be conducted on Friday, Jun 13, during the station 63 pass. This test will explore what telemetry rates can be achieved. An ESA Malargue support has been added later in the day to make up for the lost telemetry time. * Only the 70 meter stations will be used during the HGA side-lobe period. The ESA stations or DSN 34 meter stations wouldn't be able to close the loop. * Ahead has 14 passes during the week, and overall coverage is nominal. 70 meter passes are scheduled for Monday, Jun 9 (D14 at 720 kbps), Friday, Jun 13 (D63), and Saturday, Jun 14 (D63 at 720 kbps). The following passes will be carried out at 160 kbps: Tuesday, Jun 10 (D24), Thursday, Jun 12 (D26), Friday, Jun 13 (D26), and Saturday, Jun 14 (D25). The following station 26 passes will be carried out at 240 kbps: Thursday, Jun 12, and Sunday, Jun 15. An ESA Malarque pass is scheduled for Friday, Jun 13. * Behind has 10 passes during the week, and overall coverage is nominal. 70 meter passes, both at 720 kbps, are scheduled for Monday, Jun 9 (D63), and Wednesday, Jun 11 (D14). The following passes will be carried out at 160 kbps: Tuesday, Jun 10 (D55), Thursday, Jun 12 (D55), Friday, Jun 13 (D55), Saturday, Jun 14 (D54), and Sunday, Jun 15 (D25). Week 25 (Jun 16-22) * Ahead has 10 passes during the week, and overall coverage is nominal. A 70 meter pass with station 43 at 720 kbps is scheduled for Saturday, Jun 21. The following passes will be carried out at 160 kbps: Thursday, Jun 19 (D55), Friday, Jun 20 (D65), and Saturday, Jun 21 (D65). The following station 26 passes will be carried out at 240 kbps: Wednesday, Jun 18, and Sunday, Jun 22. * Behind has 11 passes during the week, and overall coverage is nominal. 70 meter passes are scheduled for Monday, Jun 16 (D63), Friday, Jun 20 (D63 at 720 kbps), and Sunday, Jun 22 (D14 at 720 kbps). The following passes will be carried out at 160 kbps: Monday, Jun 16 (D65), Tuesday, Jun 17 (D55), Wednesday, Jun 18 (D55), Thursday, Jun 19 (D54), and Saturday, Jun 21 (D25). Week 26 (Jun 23-29) * Mission operations spacecraft testing readiness review Thursday Jun 26 for Ahead, in preparation for the solar conjunction operations test Jul 7-13. * Ahead has 11 passes during the week, and overall coverage is nominal. 70 meter passes are scheduled for Thursday, Jun 26 (D43), Friday, Jun 27 (D63, D14 at 720 kbps), and Saturday, Jun 28 (D63 at 720 kbsp). The following passes will be carried out at 160 kbps: Saturday, Jun 28 (D25), and Sunday, Jun 29 (D65). * Behind has 11 passes during the week, and overall coverage is nominal. 70 meter passes are scheduled for Monday, Jun 23 (D14 at 720 kbsp), Tuesday, Jun 24 (D43 at 720 kbps), and Wednesday, Jun 25 (D63). The following passes will be carriedd out at 160 kbps: Tuesday, Jun 24 (D55), Thursday, Jun 26 (D65), Friday, Jun 27 (D55), and Saturday, Jun 28 (D55). The station 26 pass on Saturday, Jun 28, will be carried out at 240 kbps. Week 27 (Jun 30-Jul 6) * July 4 is the Independence Day holiday. * Ahead has 12 passes during the week, and overall coverage is nominal. * Behind has 10 passes during the week, and overall coverage is nominal. Solar Conjunction Status * Ahead will go into solar conjunction operations first. The HGA feed temperatures needs to be kept below 125 degrees. The current temperature on Ahead is 97 degrees, and 111 degrees on Behind. However, the temperature on Ahead is now increasing faster, while Behind has leveled off temporarily. * A test of the operational mode for solar conjuntion will be performed on Ahead during the week of Jul 7-13. On Jul 7 the instruments will be powered off, and the recorder will be read out and reconfigured for solar conjunction. On the second day (Jul 8), the spacecraft will be operated on the HGA side lobe, and a momentum dump will be conducted. On the third day (Jul 9), the spacecraft will be commanded into a reset to put it into the slowly rotating mode that it will be in during the actual conjunction. It will then be monitored for 3 days, until it autonomously resets itself. 70 meter stations have been scheduled throughout the week. The instruments will be on operational heaters. The IMU will be off, and the star tracker will be on. Once the spacecraft autonomously resets, the spacecraft will be recovered, and returned to normal HGA operations. The recorder will be emptied, and reconfigured back for science operations. Finally, the instruments will be powered back on. * If the instrument teams need any updates to EEPROM for solar conjuntion operations, the MOps needs those changes now. * The instruments on Ahead will be turned off on August 20th. The spacecraft will switch to HGA side lobe operations soon after. * The thermal analysis for solar conjunction operations hasn't arrived yet. * The expected telemetry rate is 3 kbps. * Spacecraft housekeeping data will only be available in realtime. There are no plans to do any SSR playback during side lobe operations. A very small amount of housekeeping data will be written to the SSR for ultimate playback after the conjunction period is completed. * The possibilities of getting instrument data were discussed. At last week's meeting, the possibility of getting an hour of beacon telemetry per day was discussed. The instrument teams would also like to see a few minutes of housekeeping data per day. Also, the in situ teams proposed writing a very small amount of beacon telemetry at a reduced rate to the SSR for daily playback (on the order of 1 Mb/day). However, the instrument teams were informed that the current plan is to keep the instruments turned off during the entire solar conjunction period. There was considerable discussion about this point, but the mission operations team strongly stated that there was insufficient time to put together an operations plan that would allow instruments to be on. It was stated that the primary objective of the conjunction plan is to keep the spacecraft safe. * The solar conjunction operations test for Behind will be Sep 29-Oct 6. The instruments will be powered off on Nov 14. * The current dates for solar conjunction milestones will be posted on the STEREO Data Server. * A question was raised about closing instrument doors before the instruments are turned off. * The SECCHI decontamination heaters will remain off. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 23: M Jun 02 (153) T Jun 03 (154) Momentum dumps, Ahead: 17:30 UT, Behind: 23:00 UT W Jun 04 (155) T Jun 05 (156) F Jun 06 (157) S Jun 07 (158) Ahead: LGA calibration test S Jun 08 (159) ------------------------------------------------------------------------------- Scheduled activities for Week 24: M Jun 09 (160) T Jun 10 (161) W Jun 11 (162) T Jun 12 (163) F Jun 13 (164) Ahead: HGA side-lobe test during station 63 pass S Jun 14 (165) S Jun 15 (166) ------------------------------------------------------------------------------- Scheduled activities for Week 25: M Jun 16 (167) T Jun 17 (168) W Jun 18 (169) T Jun 19 (170) F Jun 20 (171) S Jun 21 (172) S Jun 22 (173) ------------------------------------------------------------------------------- Scheduled activities for Week 26: M Jun 23 (174) T Jun 24 (175) W Jun 25 (176) T Jun 26 (177) F Jun 27 (178) S Jun 28 (179) S Jun 29 (180) ------------------------------------------------------------------------------- Scheduled activities for Week 27: M Jun 30 (181) T Jul 01 (182) W Jul 02 (183) T Jul 03 (184) F Jul 04 (185) Independence Day S Jul 05 (186) S Jul 06 (187) ------------------------------------------------------------------------------- Scheduled activities for Week 28: M Jul 07 (188) Ahead: Turn instruments off T Jul 08 (189) Ahead: Momentum dump using side lobe W Jul 09 (190) Ahead: Command spacecraft reset T Jul 10 (191) F Jul 11 (192) S Jul 12 (193) Ahead: Autonomous reset, recover spacecraft back to HGA S Jul 13 (194) Ahead: Power on instruments Notes: * Solar conjunction operations test on Ahead, Jul 7-13. All science instruments will be off during this test. ------------------------------------------------------------------------------- Upcoming events: 2014: * Aug 20 Ahead: Start of solar conjunction operations * Sep 07-Nov 15 Behind: Passage of Comet Siding Spring through HI2-B * Sep 29-Oct 6 Behind: Test of solar conjunction operations * Sep 21 MAVEN arrival at Mars * Oct 17 Behind: Comet Siding Spring encounter with Mars * Nov 14 Behind: Start of solar conjunction operations 2015: * Jan 14 - Mar 19 (TBC) Behind: Spacecraft behind Sun * Mar DAWN - Ceres arrival * Feb 11 - Jul 08 (TBC) Ahead: Spacecraft behind Sun * Aug 25 - Oct 19 (TBC) Behind: Possible interference from Sun * Jul DAWN - End of nominal mission 2016: * Jul 5 Juno arrival at Jupiter 2017: * Jul 11 Ahead: Switch downlink rate to 160 kbps * Jul 22 Behind: Switch downlink rate to 160 kbps 2018: * Mar 5 Ahead: Mercury transit