STEREO Weekly Meeting Minutes for 2017-12-05 (Week 49) 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. 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 48 (Nov 27-Dec 3) * On days 332 (Nov 28), the MOC was on portable generator power from 1752z through 1931z as commercial and backup generator power were disabled as a high voltage circuit breaker was replaced on the power substation that feeds the building. There were no tracks during this maintenance and there was no impact to STEREO MOC operations. Note that as one more high voltage breaker needs to be refurbished, one additional TBD substation maintenance will be scheduled, possibly later in December. * On day 334 (Nov 30), during the DSS-25 support for Ahead, telemetry binds dropped all command workstations for Ahead and Behind at 2205z, 5 minutes before BOT. Telemetry binds were reestablished at 2219z. This anomaly resulted in the loss of 9 minutes of real-time telemetry and monitor data. All SSR data were received. * On day 335 (Dec 1), during the DSS-34 support for Ahead, turbo decoder lock was lost briefly at 0735z, 0906z, and 0916z. This anomaly resulted in the loss of 5 frames of SSR data. * On day 337 (Dec 3), 30 minutes before the BOT with the DSS-14 support for Ahead, telemetry binds were dropped at 1650z on both Ahead and Behind command workstations due to a network issue at JPL. After restarting MOC relay and command streams, the telemetry binds were re-established at 1912z. Due to the 1.25 hour short duration of the support, no real-time telemetry or monitor data were received and no commanding was conducted. This anomaly resulted in the loss of 1.25 hours of real-time telemetry, commanding, and monitor data. All SSR data were received. See DR# G118691 for more information. * On day 336 (Dec 2), the PLASTIC SSR science partition (#17) on Ahead reached 95% full and began recording only housekeeping data at 1244z for 49 minutes due to insufficient track time. * On day 337 (Dec 3), the Ahead spacecraft reached perihelion in its orbit. * The average daily science data return for Ahead was 5.1 Gbits during this week. * On day 332 (Nov 28), during a 3 hour 4 kHz battery recovery search pattern support for Behind with DSS-63, 320 commands were transmitted during the support. All 7 points on the pattern were covered twice. * On day 335 (Dec 1) during a 3 hour 4 kHz carrier recovery search pattern support for Behind with DSS-63, 320 commands were transmitted during the support for carrier recovery. No carrier was detected by either the DSN station or the radio science receiver team. All 7 points on the pattern were covered twice. Three commands must be received sequentially to power on the transmitter. Week 49 (Dec 4-10) * Earlier today (Dec 5), the 41st SECCHI stepped calibration roll was carried out starting at 08:55 UT for perihelion in the Ahead orbit. So far, all indications are that this maneuver was successful. * 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 was carried out earlier this morning (Dec 5). There were several false locks, but no actual carrier signal was detected. An additional nominal recovery track is scheduled for Saturday, Dec 9. 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 stations 25 & 26 to maintain data return on Ahead. * A single recovery attempt for Behind is scheduled for Thursday, Dec 14. Two recovery tracks 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 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. * 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, three at 240 kbps, and three 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) * Ahead has 16 tracks during the week, and overall coverage is nominal. There are six track at 720 kbps, eight at 240 kbps, and two 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 (batter), and Saturday, Jan 20 (carrier). Other * The SECCHI HI team has requested an off-point maneuver for stray light calibration. This involves moving by up to 1 degree in the Y direction. This will be the first time this maneuver will be performed without using the gyros. The procedure for this has been tested on the simulator, and the results are being analyzed. A hardware issue on the simulator was identified, and is being addressed. The MOC expects to be able to perform this maneuver possibly later this month. The SECCHI team also has to make changes to their procedures, and will discuss a time for scheduling the maneuver once the MOC is ready. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- 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) ------------------------------------------------------------------------------- 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) 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, battery) ------------------------------------------------------------------------------- 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) T Jan 16 (016) Behind: Recovery track, DSN 63 (search pattern, battery) 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) ------------------------------------------------------------------------------- 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