STEREO Weekly Meeting Minutes for 2017-12-19 (Week 51) ANNOUNCEMENTS ------------- * The Dec 26 STEREO weekly planning meeting is canceled. 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. In some cases, the older "1 kHz" frequency acquisition sequence is used, with one day for battery recovery, and another for carrier recovery. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 50 (Dec 11-17) * On day 348 (Dec 14), during the DSS-35 support for Ahead, lost command bind as well as all telemetry binds on all command workstations for Ahead and Behind at 0529z. Command and telemetry binds were re-established at 0634z. This anomaly resulted in the loss of 1.1 hours of commanding, real-time telemetry, and monitor data. All SSR data were received. See DR #C113108 for more information. * The average daily science data return for Ahead was 5.8 Gbits during this week. * On day 348 (Dec 14), during a 2.5 hour 4 kHz carrier recovery support for Behind with DSS-63, 260 commands were transmitted during the support. No carrier was detected by either the DSN station or the radio science receiver team after attempting to power on the TWTA for 30 minutes. Transitioned to battery recovery operations for the remainder of the support which consists of repeatedly sweeping a 4 kHz uplink range and sending commands for IEM switched power and PDU 1553 interface bus off. * At present, the MOC will continue to schedule weekly attempts to recover Behind until additional guidance is provided by NASA headquarters. * SECCHI commented that the stepped calibration roll in the previous week, Dec 5, showed considerable jitter which made processing the data difficult. Much less jitter was seen in the previous calibration roll. They do not ask for the roll to be redone, but ask the MOC to look into whether the problem can be mitigated in future rolls. Week 51 (Dec 18-24) * During the Dec 19 station 55 pass for Ahead, which was ongoing at the time of the telecon, the transmitter came up late. The SSR pointers were reset. SECCHI has a large command load for their holiday schedule. * 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 has 14 tracks during the week, and overall coverage is nominal. There are three passes at 720 kbps, two at 360 kbps, and nine at 160 kbps. * A Behind recovery attempt is 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, is Christmas Day which is an APL holiday. * Tuesday Dec 26 STEREO weekly planning meeting is canceled. * Ahead has 13 tracks during the week, and overall coverage is nominal. There are five passes at 720 kbps, two at 360 kbps, two at 240 kbps, and four at 160 kbps. * Behind recovery attempts are scheduled for Monday, Dec 25 (battery search pattern), Wednesday, Dec 27 (carrier search pattern), and Saturday, Dec 30 (nominal 4kHz carrier recovery). Week 1 (Jan 1-7) * January 1 is the New Year holiday. * Ahead has 15 tracks during the week, and overall coverage is nominal. There are seven tracks at 720 kbps, two at 360 kbps, five at 240 kbps, and one at 160 kbps. * There are four recovery attempts for Behind during the week. A 1 kHz frequency acquisition pass for battery recovery will be carried out Monday, Jan 1, with the subsequent carrier recovery pass on Tuesday, Jan 1. Search pattern attempts will be carried out on Friday, Jan 5, for battery recovery, and Sunday, Jan 6, for carrier recovery. Week 2 (Jan 8-14) * Ahead has 14 tracks during the week, and overall coverage is nominal. There are seven tracks at 720 kbps, one at 360 kbps, four at 240 kbps, and two at 160 kbps. * Recovery attempts for Behind using the 1 kHz frequency acquisition sequence are scheduled on Tuesday, Jan 9 (battery) and Friday, Jan 12 (carrier). A search pattern for battery recovery is scheduled for Sunday, Jan 14. Week 3 (Jan 15-21) * Jan 15 is the Martin Luther King Day holiday. Government offices will be closed, but APL will remain open. * Ahead has 16 tracks during the week, and overall coverage is nominal. There are six tracks at 720 kbps, one at 360 kbps, eight at 240 kbps, and one at 160 kbps. * A carrier recovery search pattern track for Behind is scheduled for Tuesday, Jan 16. Recovery tracks using the 1 kHz frequency acquisition sequence are scheduled for Thursday, Jan 18 (battery), and Saturday, Jan 20 (carrier). Week 4 (Jan 22-28) * On Wednesday, Jan 24, Behind would resume 125 bps uplink on LGA assuming nominal operations. * Ahead has 13 tracks during the week, and overall coverage in nominal. There are seven tracks at 720 kbps, two at 360 kbps, and four at 240 kbps. * Weekly recovery operations for Behind continue. A battery recovery search pattern track is scheduled for Tuesday, Jan 23, and the corresponding carrier recovery search pattern track will be on Friday, Jan 26. On Sunday, Jan 28 a battery recovery 1 kHz sweep sequence is scheduled. Other * SECCHI has asked that the off-point maneuver discussed during last week's telecon be scheduled for the third or fourth week in January. * The report of a leap second at the start of 2018 reported in last week's telecon was incorrect. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 51: M Dec 18 (352) 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) ------------------------------------------------------------------------------- Scheduled activities for Week 52: M Dec 25 (359) Christmas Behind: Recovery track, DSN 63 (search pattern, battery) T Dec 26 (360) W Dec 27 (361) Behind: Recovery track, DSN 63 (search pattern, carrier) T Dec 28 (362) F Dec 29 (363) Behind: Recovery track, DSN 14 S Dec 30 (364) S Dec 31 (365) ------------------------------------------------------------------------------- Scheduled activities for Week 01: M Jan 01 (001) New Year Behind: Recovery track, DSN 14 (1 kHz, battery) T Jan 02 (002) Behind: Recovery track, DSN 63 (1 kHz, carrier) W Jan 03 (003) T Jan 04 (004) F Jan 05 (005) Behind: Recovery track, DSN 63 (search pattern, battery) S Jan 06 (006) S Jan 07 (007) Behind: Recovery track, DSN 14 (search pattern, carrier) ------------------------------------------------------------------------------- Scheduled activities for Week 02: M Jan 08 (008) T Jan 09 (009) Behind: Recovery track, DSN 63 (1 kHz, battery) W Jan 10 (010) T Jan 11 (011) F Jan 12 (012) Behind: Recovery track, DSN 63 (1 kHz, carrier) S Jan 13 (013) S Jan 14 (014) Behind: Recovery track, DSN 14 (search pattern, battery) ------------------------------------------------------------------------------- Scheduled activities for Week 03: M Jan 15 (015) Martin Luther King Day T Jan 16 (016) Behind: Recovery track, DSN 63 (search pattern, carrier) W Jan 17 (017) T Jan 18 (018) Behind: Recovery track, DSN 14 (1 kHz, battery) F Jan 19 (019) S Jan 20 (020) Behind: Recovery track, DSN 63 (1 kHz, carrier) S Jan 21 (021) ------------------------------------------------------------------------------- Scheduled activities for Week 04: M Jan 22 (022) T Jan 23 (023) Behind: Recovery track (search pattern, battery) W Jan 24 (024) T Jan 25 (025) F Jan 26 (026) Behind: Recovery track (search pattern, carrier) S Jan 27 (027) S Jan 28 (028) Behind: Recovery track (1 kHz, battery) ------------------------------------------------------------------------------- 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