STEREO Weekly Meeting Minutes for 2018-07-17 (Week 29) ANNOUNCEMENTS ------------- * The SWAVES team has pointed out that the most recent .fin telemetry files, starting with day 102 (Apr 12), have been produced as version 00 instead of incrementing from the latest .ptp file. For example, the .fin file for day 102 has the name swaves_ahead_2018_102_1_00.fin when it should be swaves_ahead_2018_102_1_05.fin, as the last .ptp file was version 04. This has been causing problems with the SWAVES processing such that the .fin files are being ignored, since their version numbers are lower than the .ptp files. The MOC traced this to a problem they had with the disk filling back in April, leading to a change in the cleanup procedures. They have now switched their scripts back to keeping the last 45 days, so that the problem should not appear in the future. The SSC offered to rename the files on the SSC website to what they should have been, but it's not clear whether the instrument teams want this or not. 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 28 (Jul 9-15) * On day 192 (Jul 11) fine pointing on Ahead was lost intermittently beginning at 0204z through 194-1304z. These occurrences were due to the reaction wheels operating at low speeds and no gyro operations during this time period. These transients can occur with no gyro operations and are not indicative of any problem with the spacecraft G&C. It is believed that the main cause is Wheel 2. After transiting through zero, it hung at minimum speed for about two days. At that low speed, the lubricants may not be getting distributed evenly enough. Once Wheel 2 progressed to higher rates, the pointing settled down. * The average daily science data return for Ahead was 6.2 Gbits during this week. * On day 190 (Jul 9), during a 3 hour 1 kHz battery recovery support for Behind with DSS-14, 225 commands were transmitted for battery state of charge recovery. Due to the duration of the support, only 25 of the 36 frequency segments were commanded. * On day 191 (Jul 10), during a 3.5 hour 1 kHz carrier recovery support for Behind with DSS-43, 380 commands were sent for transmitter carrier recovery. No carrier was detected by the station. Due to the duration of the support and the increased commands for each step, only 19 of the 36 frequency segments were commanded. Three commands must be received sequentially to power on the transmitter. * On day 192 (Jul 11), during a 4 hour 1 kHz carrier recovery support for Behind with DSS-43, 440 commands were sent for transmitter carrier recovery. No carrier was detected by the DSN station. Due to the duration of the support and the increased commands for each step, only 22 of the 36 frequency segments were commanded. Three commands must be received sequentially to power on the transmitter. 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 12 tracks during the week, and overall coverage is nominal. There are three tracks at 720 kbps, six at 360 kbps, and three at 240 kbps. * There are no recovery passes for Behind during the week. Week 31 (Jul 30-Aug 5) * Ahead has 12 tracks during the week, and overall coverage is nominal. There are six tracks at 720 kbps, three at 360 kbps, and three at 240 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, three at 360 kbps, two at 240 kbps, and one at 160 kbps. * There are no recovery passes for Behind during the week. Week 33 (Aug 13-19) * The 44th SECCHI stepped calibration roll is scheduled for Tuesday August 14th at 05:55 UT and taking 4.5 hours. This will be the midpoint roll. System momentum will be 1 N-m-s. * A project interface test with station 26 is scheduled for Sunday, Aug 19, starting at 22:55 UT. There will be no SSR commanding or instrument commanding during this pass. * Ahead has ten 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. * Recovery tracks for Behind using the double diamond search pattern are scheduled for Monday, Aug 13 (battery), Tuesday, Aug 14 and Wednesday, Aug 15 (both carrier). Week 34 (Aug 20-26) * Ahead has 14 tracks during the week, and overall coverage is nominal. There are six tracks at 720 kbps, three at 360 kbps, four at 240 kbps, and one at 160 kbps. * There are no recovery passes for Behind during the week. Week 35 (Aug 27-Sep 2) * Ahead has 11 tracks during the week, and overall coverage is currently short 4.7 hours between Monday to Tuesday. There are five tracks at 720 kbps, one at 360 kbps, two at 240 kbps, and three at 160 kbps. * There are no recovery passes for Behind during the week. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- 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) Notes: * Power system maintenance work at SSC site, Jul 19, 20-22 UT. The SSC is expected to remain up on UPS. ------------------------------------------------------------------------------- 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) ------------------------------------------------------------------------------- Scheduled activities for Week 33: M Aug 13 (225) Behind: Recovery track, DSN 14 (search, battery) T Aug 14 (226) Ahead: SECCHI stepped calibration roll, 5:55 UT Behind: Recovery track, DSN 14 (search, carrier) W Aug 15 (227) Behind: Recovery track, DSN 14 (search, carrier) T Aug 16 (228) F Aug 17 (229) S Aug 18 (230) S Aug 19 (231) Ahead: Project interface test with station 26. ------------------------------------------------------------------------------- Scheduled activities for Week 34: M Aug 20 (232) T Aug 21 (233) W Aug 22 (234) T Aug 23 (235) F Aug 24 (236) S Aug 25 (237) S Aug 26 (238) ------------------------------------------------------------------------------- Scheduled activities for Week 35: M Aug 27 (239) T Aug 28 (240) W Aug 29 (241) T Aug 30 (242) F Aug 31 (243) S Sep 01 (244) S Sep 02 (245) ------------------------------------------------------------------------------- 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