STEREO Weekly Meeting Minutes for 2014-05-04 (Week 19) ANNOUNCEMENTS ------------- * Tests will be performed of off-pointing the HGA antennas on both spacecraft, to see if minimal communication can be maintained during the long conjunction period. See below for details. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * All subsystems on both spacecraft are nominal. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 18 (Apr 28-May 4) * On day 119 (Apr 29), during the DSS-43 support for Ahead, hardware issues resulted in intermittent antenna pointing errors during the first part of the support. Once these issues were resolved, MOps repositioned all SSR pointers to recover affected data. See DR #C110167 for more information. * On day 123 (May 3), during the DSS-26 support for Ahead, the transmitter tripped off at 1752z. The subsequent transition from 2-way to 1-way resulted in the loss of 427 frames of SSR data. To avoid further data loss, MOps requested to remain 1-way for the remainder of the track. See DR #G115009 for more information. * On day 119 (Apr 29), MOps permanent macro release 1.1.20 was loaded to RAM on both spacecraft. This release removed all SSR housekeeping double playback commands from all relevant macros. * On day 120 (Apr 30), the 67th momentum dump on Ahead was executed successfully at 1500z, which imparted a delta V of 0.0873 m/sec. * On day 121 (May 1), the G&C parameter hga_stoplo was modified from 0.0 to 0.11519173 radians (6.6 degrees) in RAM on Ahead, and from 0.0 to 0.10646508 radians (6.1 degrees) in RAM on Behind. This update is intended to prevent the HGA from continuing on through lower pointing angles and capping the HGA feed temperature at a safe level. * On day 120 (Apr 30), during the DSS-43 support for Behind, the transmitter tripped off at 0202z. The subsequent transition from 2-way to 1-way resulted in the loss of 2050 frames of SSR data. To avoid further data loss, MOps requested to remain 1-way for the remainder of the track. See DR #C110170 for more information. * On day 120 (Apr 30), during the DSS-14 support for Behind, turbo decoder lock was lost briefly at 1754z and 1817z. This anomaly resulted in the loss of two frames of SSR data. * On day 121 (May 1), during the DSS-55 support for Behind, turbo decoder lock was lost between 1216z and 1229z due to a TLP issue at the station. This anomaly resulted in the loss of thirteen minutes of SSR data. See DR #M107964 for more information. * On day 122 (May 2), during the DSS-55 support for Behind, turbo decoder lock was lost briefly at 1151z. This anomaly resulted in the loss of one frame of SSR data. * On day 123 (May 3), during the DSS-25 support for Behind, turbo decoder lock was lost briefly at 1859z. This anomaly resulted in the loss of one frame of SSR data. * The average daily SSR playback volume during the week was 5.3 gigabits for Ahead, and 5.8 gigabits for Behind. Week 19 (May 5-11) * The 62nd momentum dump on Behind is scheduled for Tuesday, May 6, with ignition at 23:30 UT. * A test of the HGA on Ahead will be conducted during the station 14 coverage on Saturday, May 10. The same test will be performed on Behind the following week. The HGA will be slewed in 0.2 degree steps up to 9 degrees, and the DSN will measure the strength of the received signal. This will test whether the HGA side bands can be used for minimal communication with the satellite during the long conjunction period. The SECCHI instruments may see increased jitter; however, the IMUs will be on during this test. SECCHI should not count on this pass when calculating their data return rate. * It expected that the signal strength will be at least 20 dB down, so only a very reduced data rate can be maintained. The objective is to maintain the health of the spacecraft. It's not clear whether the space weather beacon stream can be supported; it depends on what rates can be achieved, and whether the instruments are on. It's unlikely that the volunteer beacon stations could lock on to such a weak signal. The instruments will not be on if they are unable to receive their housekeeping telemetry. * Ahead has 8 passes during the week, and overall coverage is nominal. 70 meter passes are scheduled for Tuesday, May 6 (D63 at 720 kbps), and Saturday, May 10 (D43, D14 at 720 kbps). The latter pass on May 10 will be used for the HGA test. The following passes will be carried out at 160 kbps: Thursday, May 8 (D25), and Sunday, May 4 (D55). The station 26 pass on Friday, May 9, will be carried out at 240 kbps. * Behind has 10 passes during the week, and overall coverage is nominal. 70 meter passes are scheduled for Monday, May 5 (D63 at 720 kbps), and Friday, May 9 (D43 at 720 kbps). The following passes will be carried out at 160 kbps: Tuesday, May 6 (D25), Thursday, May 8 (D55, D24), and Saturday, May 10 (D55, D25). The station 26 pass on Sunday, May 11, will be carried out at 240 kbps. Week 20 (May 12-18) * MOps macro 1.1.20 will be loaded onto EEPROM on both spacecraft on May 18. * A test of slewing the HGA on Behind will be conducted during the station 43 pass on Saturday, May 17. * Ahead has 11 passes during the week, and overall coverage is nominal. 70 meter passes are scheduled for Monday, May 12 (D14 at 720 kbps), Thursday, May 15 (D63 at 720 kbps), and Friday, May 16 (D43). The following passes will be carried out at 160 kbps: Tuesday, May 13 (D26), Wednesday, May 14 (D55), Thursday, May 15 (D25), and Saturday, May 17 (D55). The following station 26 passes will be carried out at 240 kbps: Wednesday, May 14, Friday, May 16, and Sunday, May 18. * Behind has 11 passes during the week, and overall coverage is nominal. 70 meter passes are scheduled for Monday, May 12 (D14 at 720 kbps), Friday, May 16 (D63), and Saturday, May 17 (D43). The following passes will be carried out at 160 kbps: Tuesday, May 13 (D54), Wednesday, May 14 (D54), Thursday, May 15 (D55, D25), Friday, May 16 (D25), Saturday, May 17 (D65), and Sunday, May 18 (D54). The station 26 pass on Saturday, May 17, will be carried out at 240 kbps. Week 21 (May 19-25) * The 30th SECCHI stepped calibration roll on Ahead is scheduled for May 20, starting at 14:45 UT. The system momentum is expected to be 1 N-m-s. This is the midpoint roll. * Ahead has 10 passes during the week, and overall coverage is nominal. 70 meter passes, all using station 14 at 720 kbps, are scheduled for Tuesday, May 20, Friday, May 23, and Sunday, May 25. The following passes will be carried out at 160 kbps: Wednesday, May 21 (D55), and Saturday, May 24 (D65). The following station 26 passes will be carried out at 240 kbps: Monday, May 19, and Thursday, May 22. * Behind has 11 passes during the week, and overall coverage is nominal. 70 meter passes, all at 720 kbps, are scheduled for Monday, May 19 (D63), Wednesday, May 21 (D14), and Friday, May 23 (D63). The following passes will be carried out at 160 kbps: Tuesday, May 20 (D24), Thursday, May 22 (D54), Friday, May 23 (D24), and Saturday, May 24 (D55, D15). The station 26 pass on Sunday, May 25, will be carried out at 240 kbps. Week 22 (May 26-Jun 1) * Monday, May 26, is Memorial Day * Ahead has 12 passes during the week, and overall coverage is nominal. 70 meter passes, all at 720 kbps, are scheduled for Monday, May 26 (D14), Friday, May 30 (D63), and Saturday, May 31 (D63). The following passes will be carried out at 160 kbps: Tuesday, May 27 (D55), Friday, May 30 (D26), and Sunday, Jun 1 (D25). The station 26 pass on Wednesday, May 28, will be carried out at 240 kbps. * Behind has 8 passes during the week, and overall coverage is nominal. 70 meter passes, all at 720 kbps, are scheduled for Monday, May 26 (D63), Tuesday, May 27 (D14), and Saturday, May 31 (D14). The following station 55 passes will be carried out at 160 kbps: Wednesday, May 28, Thursday, May 29, and Friday, May 30. The station 26 pass on Sunday, Jun 1, will be carried out at 240 kbps. 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. * Ahead has 11 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), 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 Thursday, Jun 5 (D14). 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. Week 24 (Jun 9-15) * Ahead has 13 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. * 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 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 (D54), Wednesday, Jun 18 (D66), Thursday, Jun 19 (D54), and Saturday, Jun 21 (D25). COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 19: M May 05 (125) T May 06 (126) Behind: Momentum dump, 23:30 UT W May 07 (127) T May 08 (128) F May 09 (129) S May 10 (130) Ahead: HGA slew test during D14 pass S May 11 (131) ------------------------------------------------------------------------------- Scheduled activities for Week 20: M May 12 (132) T May 13 (133) W May 14 (134) T May 15 (135) F May 16 (136) S May 17 (137) Behind: HGA slew test during D43 pass S May 18 (138) ------------------------------------------------------------------------------- Scheduled activities for Week 21: M May 19 (139) T May 20 (140) Ahead: SECCHI stepped calibration roll, 14:45 UT W May 21 (141) T May 22 (142) F May 23 (143) S May 24 (144) S May 25 (145) ------------------------------------------------------------------------------- Scheduled activities for Week 22: M May 26 (146) Memorial Day T May 27 (147) W May 28 (148) T May 29 (149) F May 30 (150) S May 31 (151) S Jun 01 (152) ------------------------------------------------------------------------------- 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) 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) 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) ------------------------------------------------------------------------------- Upcoming events: 2014: * Sep 07-Nov 15 Behind: Passage of Comet Siding Spring through HI2-B * Sep 21 MAVEN arrival at Mars * Oct 17 Behind: Comet Siding Spring encounter with Mars 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