STEREO Weekly Meeting Minutes for 2017-07-25 (Week 30) ANNOUNCEMENTS ------------- * There will be a Behind recovery readiness review on Friday August 11, 9am at APL. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * Ahead is operating nominally on the main lobe of the high gain antenna. * Attempts to recover Behind have transitioned from monthly schedule to a weekly schedule (every 3-days) on July 11. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 29 (Jul 17-23) * On day 199 (Jul 18), during the DSS-43 support for Ahead, turbo decoder lock was lost briefly at 200-0117z and 0205z. This anomaly resulted in the loss of 106 frames of real-time telemetry and SSR data. See DR #C112802 for more information. * On day 200 (Jul 19), during the DSS-63 support for Ahead, turbo decoder lock was lost briefly at 0812z. This anomaly resulted in the loss of 212 frames of real-time telemetry and SSR data. See DR #M110116 for more information. * On day 201 (Jul 20), during the DSS-43 support for Ahead, turbo decoder lock was lost intermittently at 202-0010z through 0046z. This anomaly resulted in the loss of 83 frames of real-time telemetry and SSR data. See DR #C112826 for more information. * On day 203 (Jul 22), the DSS-63 support for Ahead did not occur as the Madrid complex could not establish ground links for all antennas. The issue was resolved at 2200z after this Ahead support had ended. This anomaly resulted in the loss of 16.7 hours of SSR data for each instrument. See DR #M110120 for more information. The track spacing didn't work out for recovering the lost data. The problem happened during the weekend, and the problem was more complex than the operations team was able to handle. Transition to Follow the Sun operations may help with future events of this sort. * On day 204 (Jul 23), during the DSS-63 support for Ahead, turbo decoder lock was lost briefly at 1815z. This anomaly resulted in the loss of two frames of SSR data. * The average daily science data return for Ahead was 5.7 Gbits during this week. * On day 199 (Jul 18), during a 4 hour support for Behind with DSS-63, 420 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. * On day 200 (Jul 19), during a 4 hour support for Behind with DSS-43, 420 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. * On day 203 (Jul 22), during a 4 hour support for Behind with DSS-63, 420 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. Week 30 (Jul 24-30) * A 2.6 hour project interface test has been scheduled with Ahead using station 24 on Saturday, Jul 29. There will be no instrument commanding or SSR playback during this track. The downlink rate will be 160 kbps. * Ahead has 9 tracks during the week, and overall coverage is nominal. There are seven tracks at 720 kbps, one at 360 kbps, and one at 240 kbps. * Recovery tracks (four hours each) for Behind are scheduled on Monday, Tuesday, Friday, and Saturday, July 24, 25, 28, 29, all using station 63. The Radio Science Receiver will be operating during all tracks. Week 31 (Jul 31-Aug 6) * The 101st momentum dump for Ahead is scheduled for Monday, Jul 31, with ignition at 17:30 UT. This will be the 20th dump without using the gyros. * TDRS 13 has daily 40 minute launch windows starting on Thursday, Aug 3 at 13:02 UT. This is not expected to affect STEREO operations. * Ahead has 11 tracks during the week, and overall coverage is nominal. There are eight tracks at 720 kbps, one at 240 kbps, and two at 160 kbps. * Recovery tracks for Behind are scheduled for Tuesday, Friday, and Sunday, Aug 1, 4, 6, all using station 63 (all four hours 70 m support). The Radio Science Receiver will be operating during all tracks. Week 32 (Aug 7-13) * Ahead has 9 tracks during the week, and overall coverage is nominal. There are eight tracks at 720 kbps, and one at 160 kbps. * Recovery tracks for Behind are scheduled for Monday, Wednesday, and Saturday, Aug 7, 9, 12. The Radio Science Receiver will be operating during all tracks. Week 33 (Aug 14-20) * On Day 130 (Aug 18) there will be a return to service support demonstration track with Station DSS-24 for 2.6 hours. No SSR playback nor instrument commanding, and downlinking at 160 kbits/sec. * Ahead has 7 tracks during the week, and overall coverage is nominal. There are six tracks at 720 kbps, and one at 240 kbps. * Recovery tracks for Behind are scheduled for Monday, Wednesday, and Friday, Aug 14, 16, 18 (about 3.5 hours each). The Radio Science Receiver will be operating during all tracks. Week 34 (Aug 21-27) * Ahead has 9 tracks during the week, and overall coverage is nominal. There are eight tracks at 720 kbps, and one at 240 kbps. * Recovery tracks switch to a daily cadence (~4-hours 70-m time each day). During the first two days, will use a different frequency acquisition sequence (using 1 kHz steps and going down 18 steps and then back up) in case the transponder has drifted out of the currently used 4kHz range. Anticipate using this finer frequency resolution the first two days of each week, with the first track being for battery recovery, and the second track being for carrier recovery. Recovery tracks for Behind are scheduled (each about 3.5-4 hours of 70-m support) for Monday, Wednesday, and Friday, Aug 21, 23, 25. The Radio Science Receiver will be operating during all tracks. Week 35 (Aug 28-Sep 3) * The 40th SECCHI stepped calibration roll on Ahead is scheduled for Tuesday, Aug 29, starting at 11:55 UT. * Ahead has 8 tracks during the week, and overall coverage is nominal. There are six tracks at 720 kbps, and two at 240 kbps. * Recovery tracks for Behind are scheduled each day, with the older frequency acquisition sequence with the finer 1 kHz steps used on Monday and Tuesday, with the first track being for battery recovery, and the second track being for carrier recovery. Week 36 (Sep 4-10) * Monday, Sep 4, is Labor Day, which is an APL holiday. * The 102nd momentum dump on Ahead is scheduled for Wednesday, Sep 6, with ignition at 17:30 UT. * Ahead has 10 tracks during the week, and overall coverage is nominal. * Recovery tracks for Behind are scheduled each day, with the older frequency acquisition sequence with the finer 1 kHz steps used on Tuesday and Wednesday, with the first track being for battery recovery, and the second track being for carrier recovery. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 30: M Jul 24 (205) Behind: Recovery track with station 63 T Jul 25 (206) Behind: Recovery track with station 63 W Jul 26 (207) T Jul 27 (208) F Jul 28 (209) Behind: Recovery track with station 63 S Jul 29 (210) Ahead: Project interface test with station 24 Behind: Recovery track with station 63 S Jul 30 (211) ------------------------------------------------------------------------------- Scheduled activities for Week 31: M Jul 31 (212) Ahead: Momentum dump, 17:30 UT T Aug 01 (213) Behind: Recovery track with station 63 W Aug 02 (214) T Aug 03 (215) F Aug 04 (216) Behind: Recovery track with station 63 S Aug 05 (217) S Aug 06 (218) Behind: Recovery track with station 63 ------------------------------------------------------------------------------- Scheduled activities for Week 32: M Aug 07 (219) Behind: Recovery track with station 63 T Aug 08 (220) W Aug 09 (221) Behind: Recovery track with station 43 T Aug 10 (222) F Aug 11 (223) S Aug 12 (224) Behind: Recovery track with station 14 S Aug 13 (225) ------------------------------------------------------------------------------- Scheduled activities for Week 33: M Aug 14 (226) Behind: Recovery track with station 14 T Aug 15 (227) W Aug 16 (228) Behind: Recovery track with station 43 T Aug 17 (229) F Aug 18 (230) Ahead: Return-to-service track with station 24 Behind: Recovery track with station 43 S Aug 19 (231) S Aug 20 (232) ------------------------------------------------------------------------------- Scheduled activities for Week 34: M Aug 21 (233) Begin daily Behind recovery tracks Solar eclipse in the United States T Aug 22 (234) W Aug 23 (235) T Aug 24 (236) F Aug 25 (237) S Aug 26 (238) S Aug 27 (239) Note: * The first two Behind recovery passes use the original frequency acquisition sequence with the finer 1 kHz resolution. The first pass is for battery recovery, and the second is for carrier recovery. ------------------------------------------------------------------------------- Scheduled activities for Week 35: M Aug 28 (240) T Aug 29 (241) Ahead: SECCHI stepped calibration roll, 11:55 UT W Aug 30 (242) T Aug 31 (243) F Sep 01 (244) S Sep 02 (245) S Sep 03 (246) Notes: * Behind recovery attempts each day. The first two Behind recovery passes use the original frequency acquisition sequence with the finer 1 kHz resolution. The first pass is for battery recovery, and the second is for carrier recovery. ------------------------------------------------------------------------------- Scheduled activities for Week 36: M Sep 04 (247) Labor Day T Sep 05 (248) W Sep 06 (249) Ahead: Momentum dump, 17:30 UT T Sep 07 (250) F Sep 08 (251) S Sep 09 (252) S Sep 10 (253) Notes: * Behind recovery attempts each day. The Tuesday and and Wednesday Behind recovery passes use the original frequency acquisition sequence with the finer 1 kHz resolution. The first pass is for battery recovery, and the second is for carrier recovery. ------------------------------------------------------------------------------- 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