STEREO Weekly Meeting Minutes for 2017-04-11 (Week 15) ANNOUNCEMENTS ------------- * A firewall upgrade at APL is scheduled between 15-17 UT on Apr 8. The instrument teams will have to reconnect after the upgrade. * The restricted IOnet will be upgraded on Thursday, Apr 13. See below for details. 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. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 14 (Apr 3-9) * On day 094 (Apr 4), during the DSS-63 support for Ahead, initial telemetry acquisition occurred 17 minutes late at 1617z as the antenna was red. SSR pointers were repositioned to minimize data loss. All SSR data were recovered. See DR #M109911 for more information. * On day 097 (Apr 7), during the DSS-55 support for Ahead, turbo decoder lock was lost briefly at 1022z. This anomaly resulted in the loss of eight frames of real-time telemetry and SSR data. * On day 099 (Apr 9), during the DSS-36 support for Ahead, turbo decoder lock was lost intermittently between 0029z and 0039z due to heavy rain at the Canberra complex. This anomaly resulted in the loss of 3114 frames of real-time telemetry and SSR data. This is equivalent to about 2 minutes of data, and is expected to affect mostly spacecraft and SECCHI telemetry. See DR# C112631 for more information. * The average daily science data return for Ahead was 6.5 Gbits during this week. Week 15 (Apr 10-16) * Passover is between Apr 10-18. Good Friday is on Apr 14, and Easter is on Apr 16. * On Day 102 Thursday (April 13), there will be an upgrade for the restricted IO net, T1 link. Expect to lose IO net connectivity but will re-establish this in the MOC. The outage will be from 1600-2030z. * A 2.6 hour return-to-service demo track for station 25 is scheduled for Thursday, Apr 13, after the IOnet upgrade starting at 2130z for 2.5 hours. There will be no instrument commanding or SSR playback during the pass. * Ahead has 8 passes during the week, and overall coverage is nominal. There are seven passes at 720 kbps, and one at 160 kbps. * Recovery attempts for Behind are scheduled for Friday, Saturday, and Sunday, Apr 14-16. The battery recovery track on Friday will use the 80 kW transmitter on station 26 with no RSS recording. The other two tracks will use the 70 meter station 14, and will include the Radio Science Receiver. Week 16 (Apr 17-23) * Ahead has 9 passes during the week, and overall coverage is nominal. There are eight passes at 720 kbps, and one at 240 kbps. * There are no passes for Behind during the week. Week 17 (Apr 24-30) * The 98th momentum dump on Ahead is scheduled for Monday, Apr 24, with ignition at 16:00 UT. This will be the 17th momentum dump without gyros. * Ahead has 11 passes (picked up track 53 on Tuesday for 2 hours courtesy of Spitzer) during the week, and overall coverage is nominal. There are ten passes at 720 kbps, and one pass at 160 kbps. * There are no passes for Behind during the week. Week 18 (May 1-7) * Ahead has 8 passes during the week, and overall coverage is nominal. There are seven passes at 720 kbps, and one at 160 kbps. * There are no passes for Behind during the week. Week 19 (May 8-14) * DSN stations will be unavailable for a large part of the day on Thursday, May 11 for an exercise in preparation for DSN "Follow the Sun" operations. STEREO Ahead has passes just before and just after this exercise, so no problems are anticipated. * The recovery attempt for Behind during the week will use the uplink array configuration on Saturday and Sunday, May 13-14, to officially validate the technique. The configuration uses stations 24, 25, and 26 at Goldstone for uplink, with the 80 kW transmitter on station 26, and the 70 meter station 14 for downlink. The first 1.9 hours will be used with STEREO Ahead for calibration. There will be no SSR playback or instrument commanding during these Ahead passes. After calibration, the stations will switch to Behind for 2.8 hours on Saturday, and 3.7 hours on Sunday, as well as station 14 for 3.4 hours with the Radio Science Receiver. A waiver has been requested for station 26 dipping below the 27.5 degree limit on Sunday. * Ahead has 9 tracks during the week and overall coverage is nominal. There are 8 passes at 720 kbps, and one at 160 kbps. Week 20 (May 15-21) * Ahead has 11 passes during the week, and overall coverage is nominal. There are seven passes at 720 kbps, one at 360 kbps, one at 240 kbps, and two at 160 kbps. * There are no passes for Behind during the week. Week 21 (May 22-28) * Ahead has 8 passes during the week, and overall coverage is nominal. There are seven passes at 720 kbps, and one at 240 kbps. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 15: M Apr 10 (100) T Apr 11 (101) W Apr 12 (102) T Apr 13 (103) F Apr 14 (104) Behind: Battery recovery track with station 26 S Apr 15 (105) Behind: Battery recovery track with station 14 S Apr 16 (106) Behind: Carrier recovery track with station 14 ------------------------------------------------------------------------------- Scheduled activities for Week 16: M Apr 17 (107) T Apr 18 (108) W Apr 19 (109) T Apr 20 (110) F Apr 21 (111) S Apr 22 (112) S Apr 23 (113) ------------------------------------------------------------------------------- Scheduled activities for Week 17: M Apr 24 (114) Ahead: Momentum dump, 16:00 UT T Apr 25 (115) W Apr 26 (116) T Apr 27 (117) F Apr 28 (118) S Apr 29 (119) S Apr 30 (120) ------------------------------------------------------------------------------- Scheduled activities for Week 18: M May 01 (121) T May 02 (122) W May 03 (123) T May 04 (124) F May 05 (125) S May 06 (126) S May 07 (127) ------------------------------------------------------------------------------- Scheduled activities for Week 19: M May 08 (128) T May 09 (129) W May 10 (130) T May 11 (131) DSN stations down for "Follow the Sun" exercise F May 12 (132) S May 13 (133) Behind: DSN uplink array recovery attempt S May 14 (134) Behind: DSN uplink array recovery attempt ------------------------------------------------------------------------------- Scheduled activities for Week 20: M May 15 (135) T May 16 (136) W May 17 (137) T May 18 (138) F May 19 (139) S May 20 (140) S May 21 (141) ------------------------------------------------------------------------------- Scheduled activities for Week 21: M May 22 (142) T May 23 (143) W May 24 (144) T May 25 (145) F May 26 (146) S May 27 (147) S May 28 (148) ------------------------------------------------------------------------------- Upcoming events: Behind events are contingent on recovering the spacecraft. 2017: 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