STEREO Weekly Meeting Minutes for 2010-08-24 (Week 34) ANNOUNCEMENTS ------------- * The network at APL will be upgraded on Saturday, Sep 11, from 12:00-13:30 UT. The MOC will be unreachable via email or pagers during this time, but cell phones will still work. Spacecraft operations will be unaffected. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * All subsystems on both spacecraft are nominal. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 33 * On day 229 (Aug 17), during the station 26 pass for Ahead, turbo decoder lock was lost briefly at 12:05 and again at 12:25 UT. This resulted in the loss of nine frames of SECCHI SSR data. * The station 26 antenna stopped tracking at 01:51 UT during the Behind pass on day 230 (Aug 18) due to a power outage caused by a lightning strike. Tracking was restored at 02:15 UT. this resulted in the loss of 24 minutes of telemetry, 119 minutes of commanding and tracking data, and about 2 hours of SSR data for all instruments. * The average daily SSR downlink was 5.6 gigabits for Ahead, and 4.9 gigabits for Behind. Week 34 * Ahead will have a 70 meter track on Thurs. Aug 26 using station 63 in Madrid. This track will be carried out at 720 kbps and will last 3 hrs. No spacecraft telemetry will be read out during this track. * Behind will have a 70 meter track on Sunday Aug 29 using station 43 in Canberra. This track will be carried out at 720 kbps. Track duration is about 7 hours. * Overall track coverage during the week is 1.4 hours above nominal for Ahead, and 3.3 hours above nominal for Behind. Week 35 * Momentum dump #32 for Ahead during the week is scheduled for Aug 31, starting at 13:30 UT. * There will be a 70 meter track for Ahead on day 243 (Aug 31), and again on day 246 (Sep 3), and a 70 meter track for Behind on day 244 (Sep 1), all using station 63 in Madrid. These tracks will be carried out at 720 kbps. No spacecraft telemetry will be read out during the Ahead track on day 246 (Sep 3). * There will be a shadow track for Ahead on Sep 4 using station 15, overlapping coverage from station 26. This will be downlink only, and will test the upcoming CDR replacement. * Track coverage for Ahead is 3.8 hours above nominal, while track coverage for Behind is even. Week 36 * Ahead and Behind were originally scheduled to go to 8 hour track schedules this week, but that has now been pushed back to spring or summer of next year. The track coverage for weeks 36,37,38 have been undergoing adjustments to give some of this time back. This adjustment is generally done about 3 weeks ahead of time. * A Project Interface Test (PIT) has been scheduled for Ahead on Wednesday, day 251 (Sep 8) to test a new interface. A second PIT test is scheduled on Friday, day 253 (Sep 10). No SSR data will be downloaded during these tests, and no POC commanding will be performed. No in situ data should be lost because of these tests. Because there is a lot of coverage during the week, SECCHI data volume shouldn't be affected. * There are a number of 70 meter stations scheduled during the week. These tracks will be carried out at 720 kbps. 70 meter tracks for Ahead occur on days 249 (Sep 6), 252 (Sep 9) and 255 (Sep 12), all using station 63 in Madrid. Behind has 70 meter tracks on day 250 (Sep 7) using station 43 in Canberra, and on day 253 (Sep 10) using station 63 in Madrid. * The network at APL will be upgraded on Saturday, Sep 11, from 12:00-13:30 UT. The MOC will be unreachable via email or pagers during this time, but cell phones will still work. Spacecraft operations will be unaffected. * The 26th momentum dump on Behind will be carried out on day 250 (Sep 7), starting at 22:30 UT, during an 8 hour pass. * Overall coverage during the week for Ahead is even, and 1.2 hours above nominal for Behind. * Monday is the Labor Day holiday. Week 37 * Ahead has 720 kbps passes using station 63 on Monday, day 256 (Sep 13), Wednesday, day 258 (Sep 15), and Saturday, day 261 (Sep 18). * Behind has a 720 kbps pass on day 256 (Sep 13) using station 63. No spacecraft telemetry will be downlinked during this pass. * Overall coverage for the week is 1 hour over nominal for Ahead, and 4.8 hours over nominal for Behind. Week 38 * Ahead will have 720 kbps passes using station 63 on Tuesday, day 264 (Sep 21), Thursday, day 266 (Sep 23), and Friday, day 267 (Sep 24). There will be another 720 kbps on day 267 (Sep 24) using station 43. Overall, there are 14 tracks for Ahead during the week. * Behind will have a 720 kbps pass on Wednesday, day 265 (Sep 22) using station 63 in Madrid. * Overall coverage is 3.7 hours over nominal for Ahead, and 2.0 hours over nominal for Behind. Week 39 * Sep 30 marks the end of the first extended mission. * Ahead has 70 meter tracks on Monday, Sep 27, Wednesday, Sep 29, Friday, Oct 1, and Saturday, Oct 2, all using station 63 in Madrid. Overall, there are 14 tracks for Ahead during the week. * Overall coverage is 4.5 hours over nominal for Ahead, and 3.7 hours over nominal for Behind. Other * Following the regular weekly planning meeting was a discussion about telemetry rates during the extended mission. It was decided to continue using a 2 dB margin for the link calculation, but to use less restrictive limits for the weather and station performance. This will push back the switch to 160 kbps to summer of 2011. Nominal DSN track time will also be raised to 8 hours in summer 2011, and remain there for the duration. Weather is expected to adversely affect 1% or fewer of tracks. APL will develop a data product to track telemetry performance. If the performance shows a trend which would drop below acceptable limits, then the dates for telemetry rate changes would be moved forward. Another option for lowering the link margin from 2 dB to 1 dB was also discussed, but none of the parties were comfortable with this option. * One important consideration for both the SECCHI and SWAVES instruments is the distribution of missed packets. Data products are spread over a series of packets, so if a packet is missed, then all the packets in that series are affected. The effect on the data is minimized if the missed packets are bunched together. COORDINATED OBSERVATIONS ------------------------ ------------------------------------------------------------------------------- Scheduled activities for Week 34: M Aug 23 (235) T Aug 24 (236) W Aug 25 (237) T Aug 26 (238) Ahead: 720 kbps downlink on station 63 F Aug 27 (239) S Aug 28 (240) S Aug 29 (241) Behind: 720 kbps downlink on station 43 ------------------------------------------------------------------------------- Scheduled activities for Week 35: M Aug 30 (242) T Aug 31 (243) Ahead: 720 kbps downlink on station 63 Ahead: Momentum dump, 13:30 UT W Sep 01 (244) Behind: 720 kbps downlink on station 63 T Sep 02 (245) F Sep 03 (246) Ahead: 720 kbps downlink on station 63 S Sep 04 (247) Ahead: Shadow track on station 15 for testing S Sep 05 (248) ------------------------------------------------------------------------------- Scheduled activities for Week 36: M Sep 06 (249) Ahead: 720 kbps downlink on station 63 T Sep 07 (250) Behind: 720 kbps downlink on station 43 Behind: Momentum dump, 22:30 UT W Sep 08 (251) Ahead: PIT test T Sep 09 (252) Ahead: 720 kbps downlink on station 63 F Sep 10 (253) Behind: 720 kbps downlink on station 63 Ahead: PIT test S Sep 11 (254) S Sep 12 (255) Ahead: 720 kbps downlink on station 63 Notes: * Network maintenance at APL, Sep 11, 12-13:30 UT ------------------------------------------------------------------------------- Scheduled activities for Week 37: M Sep 13 (256) Ahead: 720 kbps downlink on station 63 Behind: 720 kbps downlink on station 63 T Sep 14 (257) W Sep 15 (258) Ahead: 720 kbps downlink on station 63 T Sep 16 (259) F Sep 17 (260) S Sep 18 (261) Ahead: 720 kbps downlink on station 63 S Sep 19 (262) ------------------------------------------------------------------------------- Scheduled activities for Week 38: M Sep 20 (263) T Sep 21 (264) Ahead: 720 kbps downlink on station 63 W Sep 22 (265) Behind: 720 kbps downlink on station 63 T Sep 23 (266) Ahead: 720 kbsp downlink on station 63 F Sep 24 (267) Ahead: 720 kbps downlink on station 63, and on station 43 S Sep 25 (268) S Sep 26 (269) ------------------------------------------------------------------------------- Scheduled activities for Week 39: M Sep 27 (270) Ahead: 720 kbps downlink on station 63 T Sep 28 (271) W Sep 29 (272) Ahead: 720 kbps downlink on station 63 T Sep 30 (273) End of extended mission #1 F Oct 01 (274) Ahead: 720 kbps downlink on station 63 S Oct 02 (275) Ahead: 720 kbps downlink on station 63 S Oct 03 (276) ------------------------------------------------------------------------------- Upcoming events: 2010: SECCHI Stepped calibration rolls Ahead: Nov 2 Behind: Oct 12 2011: * Spring/Summer Ahead: End use of 720 kbps on 70 m DSN subnet * Spring/Summer Behind: End use of 720 kbps on 70 m DSN subnet * Jan 12 Both: HGA calibration * Feb 6 STEREO spacecraft at 180 degree separation * Jun 27 Ahead: Switch downlink rate to 160 kbps * Jul 15 Behind: Switch downlink rate to 160 kbps * Mar 18 Messenger - Mercury orbital insertion * Jul DAWN - Vesta arrival * Jul 13 Both: HGA calibration 2012: * Jan 11 Both: HGA calibration * Jul DAWN - Vesta departure * Jul 11 Both: HGA calibration * Nov 4 Behind: Switch downlink rate to 120 kbps * Nov 13 Total solar eclipse, south Pacific 2013: * May 3 Ahead: Switch downlink rate to 120 kbps * Dec 12 Ahead: Mercury transit 2014: * Apr 29 Behind: Mercury transit 2015: * Feb DAWN - Ceres arrival * Jan 20 - Mar 28 (TBC) Behind: Spacecraft behind Sun * Mar 17 - Jul 14 (TBC) Ahead: Spacecraft behind Sun * Aug 25 - Oct 19 (TBC) Behind: Spacecraft behind Sun * Jul DAWN - End of nominal mission 2016: 2017: * Jul 11 Ahead: Switch downlink rate to 160 kbps * Jul 22 Behind: Switch downlink rate to 160 kbps 2018: * Mar 5 Ahead: Mercury transit