STEREO Weekly Meeting Minutes for 2018-06-26 (Week 26) ANNOUNCEMENTS ------------- * None INSTRUMENT and SPACECRAFT STATUS -------------------------------- * Ahead is operating nominally on the main lobe of the high gain antenna. * Behind has transitioned to a monthly schedule to attempt to recover the spacecraft. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 25 (Jun 18-24) * On day 173 (Jun 22), during the DSS-26 support for Ahead, turbo decoder lock was lost intermittently at 1954z through 1959z due to the downlink receiver transitioning to 1-way mode because the transmitter went offline at 1926z through the end-of-track. This anomaly resulted in the loss of three hours of command uplink and 2-way ranging. The anomaly also resulted in the loss of 4303 frames of real-time telemetry and SSR data. See DR #G119189 for more information. * On day 172, the 110th momentum dump was executed successfully at 2000z, which imparted an estimated delta V of 0.090 m/sec. This was the 29th momentum dump that did not use the IMU. After thruster operations completed, there was a 0.62 degree of roll angle error, which was dampened out over the next 8.5 minutes. Fine pointing stabilized 2.25 minutes after completion of the momentum dump. * The average daily science data return for Ahead was 5.7 Gbits during this week. Week 26 (Jun 25-Jul 1) * Ahead has eleven tracks during the week, and overall coverage is now nominal after a 70 meter pass was added on Monday. There are seven tracks at 720 kbps, and four at 240 kbps. * There are no recovery passes for Behind during the week. Week 27 (Jul 2-8) * A return-to-service pass for station 25 with Ahead is scheduled for Tuesday, Jul 3. There will be no SSR playback or instrument commanding during this pass. * Wednesday, Jul 4, is Independence Day, which is a holiday at APL. * Ahead has ten tracks during the week, and overall coverage is nominal. There are five tracks at 720 kbps, three at 360 kbps, and two at 240 kbsp. * There are no recovery passes for Behind during the week. Week 28 (Jul 8-15) * Ahead has twelve tracks during the week, and overall coverage is nominal. There are three tracks at 720 kbps, three at 360 kbps, and six at 240 kbps. * Recovery tracks for Behind using the 1 kHz frequency acquisition sequence are scheduled for Monday, Jul 9 (battery), and Tuesday, Jul 10 and Wednesday, Jul 11 (both carrier). Week 29 (Jul 16-22) * Ahead has 16 tracks during the week, and overall coverage is nominal. There are four tracks at 720 kbps, three at 360 kbps, and nine at 240 kbps. * There are no recovery passes for Behind during the week. * Maintenance of the power systems in the building housing the STEREO Science Center is scheduled for Jul 19, between 20-22 UT. Actual interruption of power is expected to last 5 minutes, and it is believed that critical systems can be kept online during that period. However, it is possible that all systems will need to be powered down if the maintenance takes longer than expected. Week 30 (Jul 23-29) * The 111th momentum dump on Ahead is scheduled for Tuesday, Jul 24, with ignition at 20:30 UT. This will be the 30th dump without using the gyros. * Ahead has 11 tracks during the week, and overall coverage is nominal. There are two tracks at 720 kbps, four at 360 kbps, and 5 at 240 kbps. * There are no recovery passes for Behind during the week. Week 31 (Jul 30-Aug 5) * Ahead has 10 tracks during the week, and overall coverage is nominal. There are five tracks at 720 kbps, two at 360 kbps, two at 240 kbps, and one at 160 kbps. * There are no recovery passes for Behind during the week. Week 32 (Aug 6-12) * Ahead has nine tracks during the week, and overall coverage is nominal. There are three tracks at 720 kbps, two at 360 kbps, three at 240 kbps, and one at 160 kbps. * There are no recovery passes for Behind during the week. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 26: M Jun 25 (176) T Jun 26 (177) W Jun 27 (178) T Jun 28 (179) F Jun 29 (180) S Jun 30 (181) S Jul 01 (182) ------------------------------------------------------------------------------- Scheduled activities for Week 27: M Jul 02 (183) T Jul 03 (184) Ahead: Return-to-service track with station 25 W Jul 04 (185) Independence Day T Jul 05 (186) F Jul 06 (187) S Jul 07 (188) S Jul 08 (189) ------------------------------------------------------------------------------- Scheduled activities for Week 28: M Jul 09 (190) Behind: Recovery track, DSN 14 (1 kHz, battery) T Jul 10 (191) Behind: Recovery track, DSN 43 (1 kHz, carrier) W Jul 11 (192) Behind: Recovery track, DSN 43 (1 kHz, carrier) T Jul 12 (193) F Jul 13 (194) S Jul 14 (195) S Jul 15 (196) ------------------------------------------------------------------------------- Scheduled activities for Week 29: M Jul 16 (197) T Jul 17 (198) W Jul 18 (199) T Jul 19 (200) F Jul 20 (201) S Jul 21 (202) S Jul 22 (203) ------------------------------------------------------------------------------- Scheduled activities for Week 30: M Jul 23 (204) T Jul 24 (205) Ahead: Momentum dump, 20:30 UT W Jul 25 (206) T Jul 26 (207) F Jul 27 (208) S Jul 28 (209) S Jul 29 (210) ------------------------------------------------------------------------------- Scheduled activities for Week 31: M Jul 30 (211) T Jul 31 (212) W Aug 01 (213) T Aug 02 (214) F Aug 03 (215) S Aug 04 (216) S Aug 05 (217) ------------------------------------------------------------------------------- Scheduled activities for Week 32: M Aug 06 (218) T Aug 07 (219) W Aug 08 (220) T Aug 09 (221) F Aug 10 (222) S Aug 11 (223) S Aug 12 (224) ------------------------------------------------------------------------------- Upcoming events: Behind events are contingent on recovering the spacecraft. 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