STEREO Weekly Meeting Minutes for 2018-01-30 (Week 5) 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 4 (Jan 22-28) * On day 023 (Jan 23), during the DSS-14 support for Ahead, turbo decoder lock was lost intermittently between 2015z and 2029z. This anomaly resulted in the loss of 9 frames of SSR data. * On day 026 (Jan 26), during the DSS-63 support for Ahead, turbo decoder lock was lost briefly at 1827z. This anomaly resulted in the loss of 94 frames of SSR data. See DR# M110444 for more information. * On day 026 (Jan 26), lost all telemetry binds on all command workstations for Ahead and Behind at 1953z due to an issue with Verizon maintenance. Telemetry binds were reestablished at 2028z. This anomaly did not impact operations. There have been problems recently with the connections to Marshall. Maintenance will begin tonight (Jan 30). * On day 026 (Jan 26), during the pre-calibration for the DSS-14 support for Ahead, DSN was unable to perform range calibrations and was unable to enable SNT (System Noise Temperature). These anomalies resulted in the loss of 192 minutes of ranging data, but nothing else. See DR# G118851 and G118852 for more information. * On day 023 (Jan 23) at 1700z, the 4th SECCHI HI Stray Light Offpoint Calibration event was conducted. * On day 025 (Jan 25), the 106th momentum dump was executed successfully at 1530z, which imparted an estimated delta V of 0.095 m/sec. This was the 25th momentum dump that did not use the IMU. After thruster operations complete, there was a 0.19 degree of roll angle error which was dampened out over the next 15.8 minutes. Fine pointing stabilized 7.3 minutes after completion of the momentum dump. * The average daily science data return for Ahead was 6.7 Gbits during this week. * On day 023 (Jan 23), 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 025 (Jan 25), during a 3 hour 4 kHz carrier recovery search pattern support for Behind with DSS-14, 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. * On day 028 (Jan 28), during a 3.6 hour 1 kHz battery recovery support for Behind with DSS-63, 279 commands were transmitted for battery state of charge recovery. Due to the duration of the support, only 30 of the 36 frequency segments were commanded. Week 5 (Jan 29-Feb 4) * SECCHI had a watchdog reset yesterday (Jan 29) at 11:48 UT. This was the 47th reset since launch. The instrument was recovered quickly back into operational mode by 16:34 UT. * Ahead has 14 tracks during the week, and overall coverage is nominal. There are eight tracks at 720 kbps, five at 240 kbps, and one at 160 kbps. * A carrier search pattern track for Behind was carried out Monday, Jan 29. No downlink signal was detected. The previous Behind track was actually a battery 1 kHz sweep sequence, but the track duration did not support a carrier search pattern. The 1 kHz sweep sequences will be used on Wednesday, Jan 31 (battery), and Friday, Feb 2 (carrier). A battery recovery search pattern will be carried out on Sunday, Feb 4. Week 6 (Feb 5-11) * Ahead has 16 tracks during the week, and overall coverage is nominal. There are seven tracks at 720 kbps, one at 360 kbps, and eight at 240 kbps. * Nominal 4 kHz recovery tracks for Behind are scheduled for Monday, Feb 5, and Wednesday, Feb 7. A 1 kHz carrier recovery track is scheduled for Friday, Feb 9, and a battery recovery search pattern track is scheduled for Sunday, Feb 11. Week 7 (Feb 12-18) * Ahead has 15 tracks during the week, and overall coverage is nominal. There are eleven tracks at 720 kbps, two at 360 kbps, and two at 240 kbps. * A carrier recovery search pattern track for Behind is scheduled for Tuesday, Feb 13, and 1 kHz recovery tracks are scheduled for Friday, Feb 16 (battery), and Sunday, Feb 18 (carrier). * Station 43 comes back online. Week 8 (Feb 19-25) * APL is open on Presidents Day (Monday, Feb 19). * The 42nd SECCHI stepped calibration roll is scheduled for Tuesday, Feb 20, starting at 12:30 UT and taking 4.5 hours. This will be the midpoint roll. System momentum will be 4 N-m-s. This will be the 11th stepped calibration roll without gyros. Procedure has been updated to assist with finer pointing. * Work will be performed on the JPL network for four hours starting at 22:45 UT on Monday, Feb 22. There are no STEREO tracks during this period. * Ahead has 14 tracks during the week, and overall coverage is nominal. There are eight tracks at 720 kbps, four at 360 kbps, and two at 240 kbps. * Recovery search pattern tracks for Behind are scheduled for Tuesday, Feb 20 (battery) and Wednesday, Feb 21 (carrier). 1 kHz frequency acquisition sequence recovery tracks are scheduled for Saturday, Feb 24 (battery) and Sunday, Feb 25 (carrier). Week 9 (Feb 26-Mar 4) * Ahead has 10 tracks during this week, and overall coverage is nominal. There are six tracks at 720 kbps, one at 360 kbps, and three at 240 kbps. * Recovery search pattern tracks for Behind are scheduled for Tuesday, Feb 27 (battery) and Friday, Mar 2 (carrier), and a 1 kHz frequency acquisition sequence recovery track is scheduled for Sunday, Mar 4 (battery). Week 10 (Mar 5-11) * Mercury transit for Ahead on Monday, Mar 5. The SSC estimates that Mercury will transit through the EUVI field-of-view between approximately 23:20 UT on Mar 4 and 8:15 UT on Mar 5, and through the COR1 field-of-view between 17:30 UT on Mar 4 and 14:30 UT on Mar 5. * The 107th momentum dump is scheduled for Monday, Mar 5, stating at 16:00 UT. This is the 26th dump without the gyros. * Daylight savings time in the U.S. begins Sunday, Mar 11. * Ahead has 13 tracks during this week, and overall coverage is nominal. There are two tracks at 720 kbps, four at 360 kbps, and seven at 160 kbps. * A nominal 4 kHz recovery track for Behind is scheduled for Tuesday, May 6. Search pattern tracks are scheduled for Thursday, Mar 8 (battery), and Saturday Mar 10 (carrier). Week 11 (Mar 12-18) * Ahead has 15 tracks during the week, and overall coverage is nominal. There are six tracks at 720 kbps, two at 360 kbps, six at 240 kbps, and one at 160 kbps. * A battery recovery search pattern track for Behind is scheduled for Monday, Mar 12, and a nominal 4 kHz recovery track is scheduled for Wednesday, Mar 14. 1 kHz frequency acquisition recovery tracks are scheduled for Friday, Mar 16 (battery), and Sunday, Mar 18 (carrier). COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 05: M Jan 29 (029) Ahead: SECCHI watchdog reset, 11:48-16:34 UT Behind: Recovery track, DSN 63 (search pattern, carrier) T Jan 30 (030) W Jan 31 (031) Behind: Recovery track, DSN 63 (1 kHz, battery) T Feb 01 (032) F Feb 02 (033) Behind: Recovery track, DSN 63 (1 kHz, carrier) S Feb 03 (034) S Feb 04 (035) Behind: Recovery track, DSN 63 (search pattern, battery) ------------------------------------------------------------------------------- Scheduled activities for Week 06: M Feb 05 (036) Behind: Recovery track, DSN 63 (4 kHz) T Feb 06 (037) W Feb 07 (038) Behind: Recovery track, DSN 14 (4 kHz) T Feb 08 (039) F Feb 09 (040) Behind: Recovery track, DSN 63 (1 kHz, carrier) S Feb 10 (041) S Feb 11 (042) Behind: Recovery track, DSN 14 (search pattern, battery) ------------------------------------------------------------------------------- Scheduled activities for Week 07: M Feb 12 (043) T Feb 13 (044) Behind: Recovery track, DSN 14 (search pattern, carrier) W Feb 14 (045) T Feb 15 (046) F Feb 16 (047) Behind: Recovery track, DSN 63 (1 kHz, battery) S Feb 17 (048) S Feb 18 (049) Behind: Recovery track, DSN 63 (1 kHz, carrier) ------------------------------------------------------------------------------- Scheduled activities for Week 08: M Feb 19 (050) President's Day T Feb 20 (051) Ahead: SECCHI calibration roll, 12:30 UT Behind: Recovery track, DSN 63 (search pattern, battery) W Feb 21 (052) Behind: Recovery track, DSN 43 (search pattern, carrier) T Feb 22 (053) F Feb 23 (054) S Feb 24 (055) Behind: Recovery track, DSN 63 (1 kHz, battery) S Feb 25 (056) Behind: Recovery track, DSN 63 (1 kHz, carrier) ------------------------------------------------------------------------------- Scheduled activities for Week 09: M Feb 26 (057) T Feb 27 (058) Behind: Recovery track, DSN 14 (search pattern, battery) W Feb 28 (059) T Mar 01 (060) F Mar 02 (061) Behind: Recovery track, DSN 14 (search pattern, carrier) S Mar 03 (062) S Mar 04 (063) Behind: Recovery track, DSN 14 (1 kHz, battery) ------------------------------------------------------------------------------- Scheduled activities for Week 10: M Mar 05 (064) Ahead: Mercury transit Ahead: Momentum dump, 16:00 UT T Mar 06 (065) Behind: Recovery track, DSN 43 (4 kHz) W Mar 07 (066) T Mar 08 (067) Behind: Recovery track, DSN 43 (search pattern, battery) F Mar 09 (068) S Mar 10 (069) Behind: Recovery track, DSN 43 (search pattern, carrier) S Mar 11 (070) Daylight Savings Time begins in US ------------------------------------------------------------------------------- Scheduled activities for Week 11: M Mar 12 (071) Behind: Recovery track, DSN 14 (search pattern, battery) T Mar 13 (072) W Mar 14 (073) Behind: Recovery track, DSN 14 (4 kHz) T Mar 15 (074) F Mar 16 (075) Behind: Recovery track, DSN 43 (1 kHz, battery) S Mar 17 (076) S Mar 18 (077) Behind: Recovery track, DSN 14 (1 kHz, carrier) ------------------------------------------------------------------------------- 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