STEREO Weekly Meeting Minutes for 2021-05-04 (Week 18) ANNOUNCEMENTS ------------- * None. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * Ahead is operating nominally. PLASTIC is in operational mode, but with a high background rate. * Four years after the initial loss of communications anomaly with the Behind observatory, NASA has directed to cease periodic recovery operations with the last support on October 17, 2018. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 17 (Apr 26-May 2) * On day 116 (Apr 26), during the DSS-63 support for Ahead, turbo decoder lock was lost briefly at 1803z. This anomaly resulted in the loss of 48 frames of SSR data. The MOPs team repositioned the SSR pointers during the track and recovered all the affected data. * On day 117 (Apr 27), DSS-14 successfully conducted a Return-To-Service (RTS) engineering demo track with Ahead. The purpose was to verify X-band Telemetry, Tracking and Command operations after the completion of Depot Level Maintenance. The MOC successfully received real-time telemetry and sent four commands. * On day 121 (May 1), during the DSS-14 support for Ahead, the transmitter tripped offline at 0201z, due to an open microwave interlock alarm. This anomaly resulted in the loss of 57 minutes of commanding and 6470 frames of SSR data during the downlink receiver transition from 2-way to 1-way mode. The MOPs team repositioned the SSR pointers on the subsequent DSS-63 support and recovered all the affected data. See DR #G121943 for more information. * As of day 122 (May 2), all PLASTIC systems on Ahead are behaving well, except there is a high background count rate, which the team is continuing to monitor. * The average daily science data return for Ahead was 7.0 Gbits during this week. Week 18 (May 3-9) * Ahead has twelve passes during the week, and overall coverage is nominal. There are eight passes at 720 kbps, and four at 480 kbps. * The 137th Momentum dump is scheduled for Thursday, May 6, with ignition at 20:30 UT. Week 19 (May 10-16) * Ahead has thirteen passes during the week, and overall coverage is nominal. There are eleven passes at 720 kbps, one at 480 kbps, and one at 360 kbps. One pass was switched from station 56 to 65 due to maintenance activity. * A return-to-service track for station 24 is scheduled for Wednesday, May 12, between 23:00-02:00 UT. There will be on instrument commanding or SSR playback during this track. * Between May 13 to Jul 15, the star Betelgeuse will be visible in the HI2 field-of-view if the spacecraft is rolled by 180 degrees. MOC will start the process of planning these maneuvers. Because of system momentum, these maneuvers cannot start until week 20, probably in the middle of the week. MOC suggests performing one roll per week. Week 20 (May 17-23) * Ahead has eleven tracks during the week, all at 720 kbps, and overall coverage is nominal. * The Ahead spacecraft will be rolled by 180 degrees on Wednesday, May 19, between 18-20 UT to allow the SECCHI HI-2 telescope to observe Betelgeuse. Week 21 (May 24-30) * Ahead has eleven tracks during the week, and overall coverage is nominal. There are eight tracks at 720 kbps, and three at 480 kbps. * The Ahead spacecraft will be rolled by 180 degrees on Wednesday, May 26, between 20-22 UT to allow the SECCHI HI-2 telescope to observe Betelgeuse. Week 22 (May 31-Jun 6) * Ahead has twelve tracks during the week, and overall coverage is nominal. There are eight tracks at 720 kbps, and four at 480 kbps. * Monday, May 31, is Memorial Day, which is a holiday at APL. * The Ahead spacecraft will be rolled by 180 degrees on Tuesday, Jun 1, between 16-18 UT to allow the SECCHI HI-2 telescope to observe Betelgeuse. Week 23 (Jun 7-13) * Ahead has eleven tracks during the week, and overall coverage is nominal. There are ten tracks at 720 kbps, and one at 480 kbps. * The 58th SECCHI stepped calibration roll is scheduled for Wednesday, Jun 9, starting at 16:50 UT. * The Ahead spacecraft will be rolled by 180 degrees on Friday, Jun 11, between 20-22 UT to allow the SECCHI HI-2 telescope to observe Betelgeuse. This will be the last 180 degree roll before the next momentum dump. There will not be a roll in week 24, and possibly not in week 25. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 18: M May 03 (123) T May 04 (124) End of Parker Solar Probe perihelion pass W May 05 (125) T May 06 (126) Ahead: Momentum dump, 20:30 UT F May 07 (127) S May 08 (128) S May 09 (129) Notes: * Parker Solar Probe perihelion pass, Apr 25-May 4. ------------------------------------------------------------------------------- Scheduled activities for Week 19: M May 10 (130) T May 11 (131) W May 12 (132) Ahead: Return-to-service track with station 24 T May 13 (133) F May 14 (134) S May 15 (135) S May 16 (136) ------------------------------------------------------------------------------- Scheduled activities for Week 20: M May 17 (137) T May 18 (138) W May 19 (139) Ahead: 180 degree roll to observe Betelgeuse, 18-20 UT T May 20 (140) F May 21 (141) S May 22 (142) S May 23 (143) ------------------------------------------------------------------------------- Scheduled activities for Week 21: M May 24 (144) T May 25 (145) W May 26 (146) Ahead: 180 degree roll to observe Betelgeuse, 20-22 UT T May 27 (147) F May 28 (148) S May 29 (149) S May 30 (150) ------------------------------------------------------------------------------- Scheduled activities for Week 22: M May 31 (151) Memorial Day T Jun 01 (152) Ahead: 180 degree roll to observe Betelgeuse, 16-18 UT W Jun 02 (153) T Jun 03 (154) F Jun 04 (155) S Jun 05 (156) S Jun 06 (157) ------------------------------------------------------------------------------- Scheduled activities for Week 23: M Jun 07 (158) T Jun 08 (159) W Jun 09 (160) Ahead: SECCHI stepped calibration roll, 16:50 UT T Jun 10 (161) F Jun 11 (162) Ahead: 180 degree roll to observe Betelgeuse, 20-22 UT S Jun 12 (163) S Jun 13 (164) ------------------------------------------------------------------------------- Upcoming events: Behind events are contingent on recovering the spacecraft. 2021: * May 13-Jul 15 Betelgeuse visible in SECCHI HI2 with 180 degree roll * Aug 5-15 Parker Solar Probe perihelion pass * Aug 9 Solar Orbiter Venus flyby * Aug 23 Solar Orbiter in quadrature with Earth * Aug 31 Solar Orbiter METIS roll * Sep 12-19 Solar Orbiter remote sensing window * Oct 16 Parker Solar Probe Venus flyby * Nov 5 Solar Orbiter along Sun-Earth line * Nov 17-26 Parker Solar Probe perihelion pass * Nov 27 Solar Orbiter Earth flyby 2022: * Feb 21-Mar 2 Parker Solar Probe perihelion pass * May 28-Jun 7 Parker Solar Probe perihelion pass * Sep 2-11 Parker Solar Probe perihelion pass * Sep 4 Solar Orbiter Venus flyby * Dec 7-16 Parker Solar Probe perihelion pass 2023: * Mar 13-23 Parker Solar Probe perihelion pass * May 5 Behind: Mercury transit * Jun 17-27 Parker Solar Probe perihelion pass * Jul 17 Behind: Closest approach to Earth * Aug 13 Ahead: Closest approach to Earth * Aug 21 Parker Solar Probe Venus flyby * Sep 23-Oct 3 Parker Solar Probe perihelion pass * Dec 25-Jan 3 Parker Solar Probe perihelion pass 2024: * Mar 26-Apr 4 Parker Solar Probe perihelion pass * Jun 26-Jul 5 Parker Solar Probe perihelion pass * Sep 26-Oct 5 Parker Solar Probe perihelion pass * Nov 6 Parker Solar Probe Venus flyby, in HI2-A field-of-view * Dec 20-29 Parker Solar Probe perihelion pass 2025: * Feb 18 Solar Orbiter Venus flyby * Mar 19-27 Parker Solar Probe perihelion pass * Apr 7 Ahead: Mercury transit * Jun 15-24 Parker Solar Probe perihelion pass 2026: * Dec 24 Solar Orbiter Venus flyby 2027: * Feb 1 Behind: Mercury transit 2028: * Mar 18 Solar Orbiter Venus flyby 2029: * Jun 10 Solar Orbiter Venus flyby * Jun 30 Ahead: Mercury transit 2030: * Sep 3 Solar Orbiter Venus flyby