STEREO Weekly Meeting Minutes for 2017-06-27 (Week 26) ANNOUNCEMENTS ------------- * None. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * Ahead is operating nominally on the main lobe of the high gain antenna. * Attempts to recover Behind have transitioned back to a monthly schedule. On July 11 the schedule will switch to weekly. * Next week's telecon will be held on Wednesday, July 5, because of the Independence Day holiday. The start time will still be 12:30 EDT. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 25 (Jun 19-25) * On day 170 (Jun 19), during the DSS-63 support for Ahead, turbo decoder lock was lost briefly at 0737z. This anomaly resulted in the loss of 129 frames of SSR data, which works out to a few seconds worth of telemetry. See DR #N110629 for more information. * On day 172 (Jun 21), during the DSS-15 support for Ahead, turbo decoder lock was lost briefly at 1847z. This anomaly resulted in the loss of one frame of SSR data, near the beginning of the track. * On day 173 (Jun 22), during the DSS-24 support for Ahead, turbo decoder lock was lost briefly at 174-0115z. This anomaly resulted in the loss of two frames of SSR data. * The average daily science data return for Ahead was 6.2 Gbits during this week. * The next recovery attempt for Behind will be on July 11, which is also when the recovery schedule changes from monthly to weekly. 70 meter passes will be scheduled to not be more than 3 days apart, so that if any commands manage to get in, the next pass will be before the hard command loss timer fires. * A recovery planning meeting was held this morning (Jun 27). Another meeting is expected to be scheduled in about two weeks time. Week 26 (Jun 26-Jul 2) * DSN stations were down for 14 hours yesterday (Jun 26) for a "Follow the Sun" exercise. This did not affect STEREO operations. * The 100th momentum dump on Ahead is scheduled for Thursday, Jun 29, starting at 17:30 UT. This will be the 19th dump without using the gyros. * Ahead has 13 tracks during the week, and overall coverage is nominal There are eight tracks at 720 kbps, three at 240 kbps, and two at 160 kbps. * There are no tracks for Behind during the week. Week 27 (Jul 3-9) * Tuesday, July 4, is Independence Day, which is a holiday at APL. * Ahead has 9 tracks during the week, and overall coverage is nominal. There are seven tracks at 720 kbps, one at 240 kbps, and one at 160 kbps. * There are no tracks for Behind during the week. Week 28 (Jul 10-16) * Ahead has 11 tracks during the week, and overall coverage is nominal. There are eight tracks at 720 kbps, two at 240 kbps, and one at 160 kbps. * Recovery operations for Behind switch from a monthly to a weekly schedule. Three 4 hour tracks per week are scheduled, spaced so that if any commands do reach the spacecraft, the command loss timer won't have a chance to fire before the next track. Behind recovery tracks are scheduled for Tuesday, Thursday, and Saturday, Jul 11, 13, and 15. The Radio Science Receiver will be operating during all tracks. * A question was raised about how frequently the uplink array configuration will be used. There are currently no uplink arrays scheduled. The recovery attempt last year showed that there was sufficient uplink margin with a single 70 meter station. Some additional uplink rates have been tested with Ahead to assist with the recovery. STEREO is agreeable to scheduling additional uplink array attempts if DSN needs support refining the technique. Week 29 (Jul 17-23) * Ahead has 11 tracks during the week, and overall coverage is nominal. There are six tracks at 720 kbps, two at 360 kbps, one at 240 kbps, and two at 160 kbps. * Recovery tracks for Behind are scheduled on Tuesday, Wednesday, and Saturday, Jul 18, 19, 22. The Radio Science Receiver will be operating during all tracks. Week 30 (Jul 24-30) * A 2.6 hour project interface test has been scheduled with Ahead using station 24 on Saturday, Jul 29. There will be no instrument commanding or SSR playback during this track. The downlink rate will be 160 kbps. * Ahead has 9 tracks during the week, and overall coverage is nominal. There are seven tracks at 720 kbps, one at 360 kbps, and one at 240 kbps. * Recovery tracks for Behind are scheduled on Monday, Tuesday, Friday, and Saturday, July 24, 25, 28, 29. The Radio Science Receiver will be operating during all tracks. Week 31 (Jul 31-Aug 6) * The 101st momentum dump for Ahead is scheduled for Monday, Jul 31, with ignition at 17:30 UT. This will be the 20th dump without using the gyros. * Ahead has 11 tracks during the week, and overall coverage is nominal. There are eight tracks at 720 kbps, one at 240 kbps, and two at 160 kbps. * Recovery tracks for Behind are scheduled for Tuesday, Friday, and Sunday, Aug 1, 4, 6, all using station 63. The Radio Science Receiver will be operating during all tracks. Week 32 (Aug 7-13) * Ahead has 9 tracks during the week, and overall coverage is nominal. There are eight tracks at 720 kbps, and one at 160 kbps. * Recovery tracks for Behind are scheduled for Monday, Wednesday, and Saturday, Aug 7, 9, 12. The Radio Science Receiver will be operating during all tracks. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 26: M Jun 26 (177) DSN stations down for "Follow the Sun" exercise T Jun 27 (178) W Jun 28 (179) T Jun 29 (180) Ahead: Momentum dump, 17:30 UT F Jun 30 (181) S Jul 01 (182) S Jul 02 (183) ------------------------------------------------------------------------------- Scheduled activities for Week 27: M Jul 03 (184) T Jul 04 (185) Independence Day W Jul 05 (186) T Jul 06 (187) F Jul 07 (188) S Jul 08 (189) S Jul 09 (190) ------------------------------------------------------------------------------- Scheduled activities for Week 28: M Jul 10 (191) T Jul 11 (192) Behind: Recovery track with station 63 W Jul 12 (193) T Jul 13 (194) Behind: Recovery track with station 43 F Jul 14 (195) S Jul 15 (196) Behind: Recovery track with station 43 S Jul 16 (197) Notes: * Start of weekly recovery attempts to recovery Behind spacecraft. ------------------------------------------------------------------------------- Scheduled activities for Week 29: M Jul 17 (198) T Jul 18 (199) Behind: Recovery track with station 63 W Jul 19 (200) Behind: Recovery track with station 43 T Jul 20 (201) F Jul 21 (202) S Jul 22 (203) Behind: Recovery track with station 63 S Jul 23 (204) ------------------------------------------------------------------------------- Scheduled activities for Week 30: M Jul 24 (205) Behind: Recovery track with station 63 T Jul 25 (206) Behind: Recovery track with station 63 W Jul 26 (207) T Jul 27 (208) F Jul 28 (209) Behind: Recovery track with station 63 S Jul 29 (210) Ahead: Project interface test with station 24 Behind: Recovery track with station 63 S Jul 30 (211) ------------------------------------------------------------------------------- Scheduled activities for Week 31: M Jul 31 (212) Ahead: Momentum dump, 17:30 UT T Aug 01 (213) Behind: Recovery track with station 63 W Aug 02 (214) T Aug 03 (215) F Aug 04 (216) Behind: Recovery track with station 63 S Aug 05 (217) S Aug 06 (218) Behind: Recovery track with station 63 ------------------------------------------------------------------------------- Scheduled activities for Week 32: M Aug 07 (219) Behind: Recovery track with station 63 T Aug 08 (220) W Aug 09 (221) Behind: Recovery track with station 43 T Aug 10 (222) F Aug 11 (223) S Aug 12 (224) Behind: Recovery track with station 14 S Aug 13 (225) ------------------------------------------------------------------------------- Upcoming events: Behind events are contingent on recovering the spacecraft. 2017: * Aug 21 Behind: Switch to daily recovery attempts 2018: * Mar 5 Ahead: Mercury transit 2019: * Mar Ahead: Switch downlink rate to 240 kbps for 34 meter * Apr Behind: Switch downlink rate to 240 kbps for 34 meter 2020: * May Behind: Switch downlink rate to 360 kbps for 34 meter * Jun Ahead: Switch downlink rate to 360 kbps for 34 meter * Jun Behind: Switch downlink rate to 480 kbps for 34 meter * Sep Ahead: Switch downlink rate to 480 kbps for 34 meter 2021: * Jul Behind: Switch downlink rate to 720 kbps for 34 meter * Aug Ahead: Switch downlink rate to 720 kbps for 34 meter 2022: 2023: * May 5 Behind: Mercury transit * Jul 17 Behind: Closest approach to Earth * Aug 13 Ahead: Closest approach to Earth 2024: 2025: * Apr 7 Ahead: Mercury transit 2026: 2027: * Feb 1 Behind: Mercury transit 2028: 2029: * Jun 30 Ahead: Mercury transit