STEREO Weekly Meeting Minutes for 2017-03-28 (Week 13) 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 12 (Mar 20-26) * On day 079 (Mar 20), during the DSS-63 support for Ahead, turbo decoder lock was lost at 0951z. This anomaly resulted in the loss of eight frames of SSR data. * On day 084 (Mar 25), during the DSS-43 support for Ahead, turbo decoder lock was lost intermittently between 0610z and 0729z. This anomaly resulted in the loss of 35 frames of SSR data and three frames of real-time telemetry. * On day 085 (Mar 26), during the DSS-63 support for Ahead, turbo decoder lock was lost intermittently between 0807z and 0826z due to rain at the Madrid complex. This anomaly resulted in the loss of 10,602 frames of real-time and SSR data. Most of the loss was in spacecraft and SECCHI telemetry, and was equivalent to about 2 minutes worth of data. See DR# M109982 for more information. * On day 081 (Mar 22), the 97th momentum dump on Ahead was executed successfully at 2030z, which imparted an estimated delta V of 0.101 m/sec. This was the 16th momentum dump that did not use the IMU. After thruster operations completed, there was a 0.83 degree of roll angle error which was dampened out over the next 14.5 minutes. Fine pointing stabilized 2.3 minutes after completion of the momentum dump. * The average daily science data return for Ahead was 6.2 Gbits during this week. * The next recovery attempts for Behind are scheduled for April 14-16. * A telecon on engineering recommendations for Behind recovery will take place later in the afternoon (Mar 28). Week 13 (Mar 27-Apr 2) * Ahead has 11 passes during the week, and overall coverage is nominal. There are six passes at 720 kbps, four at 240 kbps, and one at 160 kbps. * There are no passes for Behind during the week. Week 14 (Apr 3-9) * A firewall upgrade at APL is scheduled between 15-17 UT on Saturday Apr 8. The instrument teams will have to reconnect after the upgrade. The next track starts around 00:25 UT. * Ahead has 10 passes during the week, and overall coverage is nominal. There are eight passes at 720 kbps, and two passes at 240 kbps. * There are no passes for Behind during the 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 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. 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 10 passes during the week, and overall coverage is nominal. There are nine passes at 720 kbps, and on 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. If necessary, time can be requested from the ESA stations. * Ahead has 9 tracks during the week and overall coverage is nominal. There are 8 passes at 720 kbps, and one at 160 kbps. * 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, which will include the Radio Science Receiver. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 13: M Mar 27 (086) T Mar 28 (087) W Mar 29 (088) T Mar 30 (089) F Mar 31 (090) S Apr 01 (091) S Apr 02 (092) ------------------------------------------------------------------------------- Scheduled activities for Week 14: M Apr 03 (093) T Apr 04 (094) W Apr 05 (095) T Apr 06 (096) F Apr 07 (097) S Apr 08 (098) S Apr 09 (099) ------------------------------------------------------------------------------- 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 ------------------------------------------------------------------------------- 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