STEREO Weekly Meeting Minutes for 2017-11-14 (Week 46) ANNOUNCEMENTS ------------- * None INSTRUMENT and SPACECRAFT STATUS -------------------------------- * Ahead is operating nominally on the main lobe of the high gain antenna. * Behind has transitioned to a weekly schedule to attempt to recover the spacecraft. Passes are scheduled approximately every three days to keep within the 72 hour command loss timer. Typically, Two of those days use a search pattern consisting of two diamonds, based on the estimated uncertainty in the ephemeris. The double diamond pattern is executed twice, once to send commands, and then again 40 minutes later to listen for the carrier. An additional pass uses the standard configuration. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 45 (Nov 6-12) * On Day 310, Monday Nov 6, Station 15 support, command bind was dropped at 2159 UT due to a network issue at APL. The command bind was re-established at 2258 UT and resulted in a loss of 1-hr of commanding. All SSR data was received. * On Day 310, Monday Nov 6, PLASTIC SSR science partitions, #17 reached 95% full for 5.8 hours which is when recording science data stops (housekeeping recording continues) at 0911 UT and again later on day 310, at 2049 UT for about 1.2 hours. This was due to a late AOF (acquisition of signal) on the previous week (day 307) since there is limited coverage of 70-m stations during this particular time of year. * On Day 314, Friday Nov 10, station 14 support, initial acquisition of telemetry was 14 minutes late which occurred at 1749 UT which was due to an operator error at the station. Station was trouble shooting another issue and so the track got started late. However, all episode data was recovered, resulting in a loss of 14-min real time telemetry, tracking and commanding data. This late start resulted in a late start Monday when the recorder filled up. * STA operating nominally * Ahead has 18 tracks during the week, and overall coverage is nominal. There are two tracks at 720 kbps, three at 240 kbps, and thirteen at 160 kbps. Ahead average daily science data return was 4.9 Gb. * Tracks to recover Behind switch to a weekly schedule, with tracks scheduled to keep within the 3 day onboard timer. Behind recovery tracks are scheduled for Tuesday, Friday, and Saturday. The Tuesday and Friday passes will use the double diamond search pattern, with the first for battery recovery, and the second for carrier recovery. All operated nominally, although the DSN and the radio science receiver both did not detect a downlink carrier. Continuing with weekly coverage through the end of the year. Currently evaluating the proposed coverage for 2018. Week 46 (Nov 13-19) * Monday (day 317), Nov 13, had a 2.2 hour demonstration track with station 25 is scheduled for Monday, Nov 13 to test a new version of the tracking, telemetry, and commanding software DSN software version 1.4. Commands went up and data was received successfully. There will be no instrument commanding or SSR playback during this track. The downlink rate will be 160 kbps. After this demo, STEREO will continue to use the new software. * Wednesday (day 319), Nov 15, The 104th momentum dump on Ahead is scheduled with ignition at 16:00 UT. This will be the 23rd dump without using the gyros. * Ahead has 16 tracks during the week, and overall coverage is nominal. There is one track at 720 kbps, three at 240 kbps, and twelve at 160 kbps. Two of those tracks use ESA stations. * Behind continues with weekly recovery tracks every three days. On Monday 260 commands were sent but did not hear from Behind. Double diamond search patterns for Behind recovery are scheduled for Thursday, Nov 16 (battery) and Saturday, Nov 19 (carrier). Week 47 (Nov 20-26) * Thursday, Nov 23, is Thanksgiving. Both Thursday and Friday, Nov 23-24, are holidays at APL. * Ahead has 17 tracks during the week, and overall coverage is nominal. There are six tracks at 360 kbps, one track at 240 kbps, and ten at 160 kbps. The data margins have been reanalyzed, and it was determined that two of the newer stations, DSN-35 and DSN-36 at Canberra, can have their nominal rates increased to 240 kbps, with a boost to 360 kbps when the entire pass is at high elevation. * Double diamond search patterns for Behind recovery are scheduled for Tuesday, Nov 21 (battery) and Wednesday, Nov 22 (carrier). Another recovery track is scheduled for Saturday, Nov 25. Week 48 (Nov 27-Dec 3) * Ahead reaches perihelion on Dec 3. * Ahead has 15 tracks during the week, and overall coverage is currently calculated to be short by about 8 hours of 70 meter time between Sunday and the following Tuesday. However, several tracks have been bumped up to 360 kbps, and the amount of data loss may diminish. Ahead comes in even for mission requirements due to stations 35 & 36 increasing the data rates allowing all the data to be retrieved for the in-situ instruments for week 48. Also moved one of the behind tracks to Ahead to help out with data recovery. There is one track at 720 kbps, three at 360 kbps, three at 240 kbps, and eight at 160 kbps. * Only two recovery tracks scheduled for Behind Tuesday, Nov 28 (battery) and Friday, Dec 1 (carrier). Week 49 (Dec 4-10) * On Tuesday (Day 338), Dec 5, The 41st SECCHI stepped calibration roll is scheduled starting at 08:55 UT for perihelion in the Ahead orbit. System momentum will be about 1 N-m-s. This will be the perihelion roll, and will be the 10th roll without gyros. * Ahead has 15 tracks during the week, and overall coverage is nominal. There are three tracks at 720 kbps, three at 360 kbps, one at 240 kbps, and eight at 160 kbps. * A double diamond carrier search pattern for Behind is scheduled for Tuesday, Dec 5 (carrier). An additional recovery track is scheduled for Saturday, Dec 9 (carrier). A 70 meter pass on Wednesday has been moved to Ahead to maintain science data return. Week 50 (Dec 11-17) * Ahead has 17 tracks during the week, and overall coverage is now nominal. Two 70 meter passes for Behind have been reallocated to Ahead. There are three passes at 720 kbps, five at 360 kbps, one at 240 kbps, and eight at 160 kbps. Using the station 25 & 26 to maintain data return on Ahead. * A single recovery attempts for Behind is scheduled for Thursday, Dec 14. Two recovery track were switched to Ahead to maintain data return. Week 51 (Dec 18-24) * Thursday, Dec 21st, the 105th momentum dump on Ahead is scheduled with ignition at 16:00 UT. This will be the 24th dump without using the gyros. * Ahead 14 tracks during the week. There are three passes at 720 kbps, one at 360 kbps, one at 240 kbps, and nine at 160 kbps. * Behind recovery attempts are scheduled for Saturday, Dec 23. The Saturday attempt will be a double diamond search pattern for carrier recovery. Two recovery tracks needed to be reallocated to Ahead. Week 52 (Dec 25-31) * Monday, Dec 25, Christmas Day which is an APL holiday. * Ahead 14 tracks during the week, There are five passes at 720 kbps, two at 360 kbps, two at 240 kbps, and ten at 160 kbps. * Behind recovery attempts are scheduled for Monday (battery), Dec 25 (carrier), and Saturday (nominal 4kHz carrier recovery), Dec 30. * For 2018, will have two 70-m stations available for about a year from Oct-Dec in 2018. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 46: M Nov 13 (317) Ahead: Demonstration track with station 25 Behind: Recovery track, DSN 63 T Nov 14 (318) W Nov 15 (319) Ahead: Momentum dump, 16:00 UT T Nov 16 (320) Behind: Recovery track, DSN 63 (search pattern, battery) F Nov 17 (321) S Nov 18 (322) Behind: Recovery track, DSN 63 (search pattern, carrier) S Nov 19 (323) ------------------------------------------------------------------------------- Scheduled activities for Week 47: M Nov 20 (324) T Nov 21 (325) Behind: Recovery track, DSN 63 (search pattern, battery) W Nov 22 (326) Behind: Recovery track, DSN 14 (search pattern, carrier) T Nov 23 (327) Thanksgiving F Nov 24 (328) APL holiday S Nov 25 (329) Behind: Recovery track, DSN 14 S Nov 26 (330) ------------------------------------------------------------------------------- Scheduled activities for Week 48: M Nov 27 (331) T Nov 28 (332) Behind: Recovery track, DSN 63 (search pattern, battery) W Nov 29 (333) T Nov 30 (334) F Dec 01 (335) Behind: Recovery track, DSN 63 (search pattern, carrier) S Dec 02 (336) S Dec 03 (337) Ahead: Perihelion Notes: * Track coverage for Ahead is short during the week, and data gaps may occur. ------------------------------------------------------------------------------- Scheduled activities for Week 49: M Dec 04 (338) T Dec 05 (339) Ahead: SECCHI stepped calibration roll, 08:55 UT Behind: Recovery track, DSN 63 (search pattern, carrier) W Dec 06 (340) T Dec 07 (341) F Dec 08 (342) S Dec 09 (343) Behind: Recovery track, DSN 63 S Dec 10 (344) Notes: * Data gaps may occur due to track coverage shortages in previous week. ------------------------------------------------------------------------------- Scheduled activities for Week 50: M Dec 11 (345) T Dec 12 (346) W Dec 13 (347) T Dec 14 (348) Behind: Recovery track, DSN 63 F Dec 15 (349) S Dec 16 (350) S Dec 17 (351) ------------------------------------------------------------------------------- Scheduled activities for Week 51: M Dec 18 (352) Behind: Recovery track, DSN 63 T Dec 19 (353) W Dec 20 (354) T Dec 21 (355) Ahead: Momentum dump, 16:00 UT F Dec 22 (356) S Dec 23 (357) Behind: Recovery track, DSN 14 (search pattern, carrier) S Dec 24 (358) Notes: * Track coverage for Ahead is short during the week, and data gaps may occur. ------------------------------------------------------------------------------- Scheduled activities for Week 52: M Dec 25 (359) Christmas Day ; Behind: Recovery track (carrier) T Dec 26 (360) W Dec 27 (361) T Dec 28 (362) F Dec 29 (363) S Dec 30 (364) Behind: Recovery track (search pattern, carrier) S Dec 31 (365) Notes: * Track coverage for Ahead is short during the week, and data gaps may occur. ------------------------------------------------------------------------------- Upcoming events: Behind events are contingent on recovering the spacecraft. 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