STEREO Weekly Meeting Minutes for 2011-08-23 (Week 34) ANNOUNCEMENTS ------------- * There have been some late track changes for Friday, Aug 26. See below for details. * A new procedure for raising the telemetry rates when the spacecraft elevation is above 25 degrees for the entire pass will be tested on the Behind spacecraft on Aug 29. See below for details. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * All subsystems on both spacecraft are nominal. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 33 (Aug 15-21) * On day 233 (Aug 21), the SECCHI Ahead instrument reset at 23:47:24z. The SECCHI team reconfigured the instrument to operational mode at 234-1300z the next day. This was the 23rd reset of SECCHI on the Ahead spacecraft. The last reset was on May 30. * On day 228 (Aug 16), during the pre-calibration for the DSS 65 support for Behind, the SLE telemetry bind failed. A second telemetry bind was successful. To date, about a dozen SLE telemetry binds have failed, which means that about 1% of the SLE telemetry binds fail on the first attempt; all succeed on the second attempt. This has had no effect yet on data recovery, but sometimes cause telemetry to be late at the MOC. The cause is being investigated by the DSN and APL. All SSR data were recovered. See DR# N107535 for more information. * On day 229 (Aug 17), during the DSS 65 support for Behind, turbo decoder lock was lost briefly beginning at 1918z. This resulted in the loss of five frames of SSR data. See DR# N107545 for more information. * On day 233 (Aug 21), during the DSS 54 support, telemetry lock was lost beginning at 1721z through 1724z due to heavy rain at Madrid. This resulted in the loss of several minutes of SSR data. See DR# M106434 for more information. * The average daily SSR downlink volume was 4.8 gigabits for Ahead, and 5.0 gigabits for Behind. Week 34 (Aug 22-28) * Turbo decoder lock was lost briefly during the station 63 track for Ahead on Monday (Aug 22) at 11:01 UT. This resulted in the loss of a few frames of data. * Turbo decoder lock was lost briefly on Tuesday (Aug 23) at 06:59 UT, leading to the loss of a couple of frames of data. * The 40th momentum dump on Ahead was scheduled for Wednesday, Aug 24, starting at 15:00 UT. It has since been rescheduled for Thursday, Aug 25, starting at 12:30 due to problems at the station. * The 34th momentum dump on Behind is scheduled for Wednesday, Aug 24, starting at 18:00 UT. * There have been some late track changes for Behind on Friday, Aug 26. A 3.4 hour station 55 support has been added, and the subsequent station 26 support has been shortened by 2.2 hours. These changes are reflected in the weekly schedules. * Ahead has 480 kbps passes on Monday, Aug 22 (D63), Wednesday, Aug 24 (D14), Friday, Aug 26 (D63), Saturday, Aug 27 (D14), and Sunday, Aug 28 (D14). There are 11 passes during the week, and overall coverage is nominal. * Behind has a 480 kbps pass on Monday, Aug 22 using station 43. There are 15 passes during the week, and overall coverage is 6.8 hours above nominal. Week 35 (Aug 29-Sep 4) * When the elevation of the spacecraft is above 25 degrees in elevation, there is a gain in the signal. This brings up the possibility of increasing the telemetry rate for passes where the elevation is above 25 degrees for the entire pass. This will be tested on the Behind spacecraft on Monday, Aug 29. The 70 meter station 43 pass on that day will be conducted at 720 kbps, and the following station 55 pass will be conducted at 240 kbps. If successful, this procedure will be continued whenever the entire track is above 25 degrees. These rates will be reflected in the weekly schedules. * A question was raised whether it was possible to switch rates during a track. This is mainly a coordination issue between the MOC and DSN, and requires that the track be attended. * Ahead has 480 kbps passes on Monday, Aug 29 (D63), Tuesday, Aug 30 (D14), Wednesday, Aug 31 (D63), Thursday, Sep 1 (D14), Friday, Sep 2 (D14), and Sunday, Sep 4 (D14). There are 11 passes during the week, and overall coverage is nominal. * Behind has 480 kbps passes on Monday, Aug 29 (D43, 720 kbps), Wednesday, Aug 31 (D14), and Thursday, Sep 1 (D63). There are 14 passes during the week, and overall coverage is 4.6 hours above nominal. Week 36 (Sep 5-11) * Monday, Sep 5 is Labor Day. APL will be closed for the holiday. * Thursday, Sep 8, at 12:37 UT is the opening of the launch window for the GRAIL mission. This is a very intense mission, with two spacecraft, lasting just 9 months, and will require a lot of track time. This will affect the DSN scheduling for STEREO. Each spacecraft will share the view direction with GRAIL two weeks out of every month. The project is looking into getting support from ESA stations to cover the shortfall. Contingency planning in case of a launch slip is ongoing for the five days starting Sep 8. Contingency planning is expected to mostly affect Ahead. * Ahead has 480 kbps passes on Tuesday, Sep 6 (D14), Thursday, Sep 8 (D43), Friday, Sep 9 (D63 and D14), and Saturday, Sep 10 (D43). There are 11 tracks during the week, and overall coverage is nominal. * Behind has 480 kbps passes on Monday, Sep 5 (D43), Wednesday, Sep 7 (D43), and Saturday, Sep 10 (D63). There are 14 tracks during the week, and overall coverage is nominal. Week 37 (Sep 12-18) * The external network switch at APL will be upgraded on Monday, Sep 12, from 22-24 UT. This will be between tracks. Telemetry connections from the instrument teams may be affected. * Ahead has 480 kbps passes on Monday, Sep 12 (D14), Tuesday, Sep 13 (D63), Wednesday, Sep 14 (D14), Thursday, Sep 15 (D63), Friday, Sep 16 (D63), and Saturday, Sep 17 (D63). There are 10 passes during the week, and overall coverage is nominal. * Behind has 480 kbps passes on Monday, Sep 12 (D43 and D63), Tuesday, Sep 13 (D63), Wednesday, Sep 14 (D63), Thursday, Sep 15 (D63), Friday, Sep 16 (D43 and D63), Saturday, Sep 17 (D14), and Sunday, Sep 18 (D63). There are 10 passes during the week, and overall coverage is nominal. * There is a gap of 17 days in coverage from southern hemisphere stations for the Ahead spacecraft starting in week 37, from days 253-270 (Sep 10-27). This will affect the accuracy of the ephemeris calculations. Use of the ESA New Norcia station would mitigate this problem. However, since there will be three weeks of tracking before this outage, there should be no problem with the ephemeris calculations. Week 38 (Sep 19-25) * Ahead has 480 kbps passes on Thursday, Sep 22 (D14), and Friday, Sep 23 (D63). There are 9 passes during the week, and overall coverage is nominal. * Behind has 480 kbps passes on Monday, Sep 19 (D63), Tuesday, Sep 20 (D63), Wednesday, Sep 21 (D63), Thursday, Sep 22 (D63), Friday, Sep 23 (D63), Saturday, Sep 24 (D43 and D63), and Sunday, Sep 25 (D63). However, many of these 70 meter passes are short. There are 11 passes during the week. Coverage is about two hours short on Thursday, Sep 22, and an hour short on Friday, Sep 23. This may be close for the in situ instruments. Week 39 (Sep 26 - Oct 2) * Ahead has 480 kbps passes on Tuesday, Sep 27 (D14 and D43), Wednesday, Sep 28 (D14), and Thursday, Sep 29 (D14). There are 11 passes during the week. Coverage is about 1.6 hours short on Monday, Sep 26. * Behind has 480 kbps passes on Tuesday, Sep 27 (D14), Wednesday, Sep 28 (D14), Friday, Sep 30 (D63), and Saturday, Oct 1 (D63). There are 9 passes during the week, and coverage is short about 2-4 hours each day for Tuesday-Thursday, Sep 27-29, or 9 hours in total. Some data may be lost. Week 40 (Oct 3-9) * The 41st momentum dump on Ahead is scheduled for Tuesday, Oct 4, with ignition starting at 13:30 UT. * The 35th momentum dump on Behind is also scheduled for Tuesday, Oct 4, with ignition starting at 15:00 UT. * Ahead has 480 kbps passes on Monday, Oct 3 (D63), Tuesday, Oct 4 (D63), Thursday, Oct 6 (D14 and D43), Saturday, Oct 8 (D14), and Sunday, Oct 9 (D63). There are 12 passes during the week, and coverage is short about 1.2 hours each on both Wednesday and Thursday, Oct 5-6. There is a potential for data loss. * Behind has 480 kbps passes on Monday, Oct 3 (D63), Wednesday, Oct 5 (D14), and Sunday, Oct 9 (D14). There are 11 passes during the week, and overall coverage is nominal. Week 41 (Oct 10-16) * Ahead has 480 kbps passes on Monday, Oct 10 (D63), Thursday, Oct 13 (D14), Friday, Oct 14 (D63), Saturday, Oct 15 (D43), and Sunday, Oct 16 (D63 and D43). There are 13 passes during the week, and overall coverage is nominal. * Behind has 480 kbps passes on Tuesday, Oct 11 (D14 and D63), Wednesday, Oct 12 (D14), Saturday, Oct 15 (D43 and D14), and Sunday, Oct 16 (D43). There are 13 passes during the week, and overall coverage is short 4.5 hours, mostly on Friday, Oct 14. Other * A question was raised about the additional telemetry being brought down during the momentum dumps to debug any possible problems with the STE door. No problems have been seen with the STE door since the additional telemetry was enabled. COORDINATED OBSERVATIONS ------------------------ ------------------------------------------------------------------------------- Scheduled activities for Week 34: M Aug 22 (234) Ahead: Recovery from SECCHI watchdog reset, 13:00 UT Ahead: 480 kbps downlink on station 63 Behind: 480 kbps downlink on station 43 T Aug 23 (235) W Aug 24 (236) Behind: Momentum dump, 18:00 UT Ahead: 480 kbps downlink on station 14 T Aug 25 (237) Ahead: Momentum dump, 12:30 F Aug 26 (238) Ahead: 480 kbps downlink on station 63 S Aug 27 (239) Ahead: 480 kbps downlink on station 14 S Aug 28 (240) Ahead: 480 kbps downlink on station 14 ------------------------------------------------------------------------------- Scheduled activities for Week 35: M Aug 29 (241) Ahead: 480 kbps downlink on station 63 Behind: 720 kbps downlink on station 43 Behind: 240 kbps downlink on station 55 T Aug 30 (242) Ahead: 480 kbps downlink on station 14 W Aug 31 (243) Ahead: 480 kbps downlink on station 63 Behind: 480 kbps downlink on station 14 T Sep 01 (244) Ahead: 480 kbps downlink on station 14 Behind: 480 kbps downlink on station 63 F Sep 02 (245) Ahead: 480 kbps downlink on station 14 S Sep 03 (246) S Sep 04 (247) Ahead: 480 kbps downlink on station 14 Notes: * Test of increasing the telemetry rate when the spacecraft elevation is above 25 degrees on Behind on Aug 29. ------------------------------------------------------------------------------- Scheduled activities for Week 36: M Sep 05 (248) Behind: 480 kbps downlink on station 43 T Sep 06 (249) Ahead: 480 kbps downlink on station 14 W Sep 07 (250) Behind: 480 kbps downlink on station 43 T Sep 08 (251) Ahead: 480 kbps downlink on station 43 F Sep 09 (252) Ahead: 480 kbps downlink on stations 63 and 14 S Sep 10 (253) Ahead: 480 kbps downlink on station 43 Behind: 480 kbps downlink on station 63 S Sep 11 (254) ------------------------------------------------------------------------------- Scheduled activities for Week 37: M Sep 12 (255) Ahead: 480 kbps downlink on station 14 Behind: 480 kbps downlink on stations 43 and 63 T Sep 13 (256) Ahead: 480 kbps downlink on station 63 Behind: 480 kbps downlink on station 63 W Sep 14 (257) Ahead: 480 kbps downlink on station 14 Behind: 480 kbps downlink on station 63 T Sep 15 (258) Ahead: 480 kbps downlink on station 63 Behind: 480 kbps downlink on station 63 F Sep 16 (259) Behind: 480 kbps downlink on stations 43 and 63 S Sep 17 (260) Ahead: 480 kbps downlink on station 63 Behind: 480 kbps downlink on station 14 S Sep 18 (261) Behind: 480 kbps downlink on station 63 ------------------------------------------------------------------------------- Scheduled activities for Week 38: M Sep 19 (262) Behind: 480 kbps downlink on station 63 T Sep 20 (263) Behind: 480 kbps downlink on station 63 W Sep 21 (264) Behind: 480 kbps downlink on station 63 T Sep 22 (265) Ahead: 480 kbps downlink on station 14 Behind: 480 kbps downlink on station 63 F Sep 23 (266) Ahead: 480 kbps downlink on station 63 Behind: 480 kbps downlink on station 63 S Sep 24 (267) Behind: 480 kbps downlink on stations 43 and 63 S Sep 25 (268) Behind: 480 kbps downlink on station 63 ------------------------------------------------------------------------------- Scheduled activities for Week 39: M Sep 26 (269) T Sep 27 (270) Ahead: 480 kbps downlink on stations 14 and 43 Behind: 480 kbps downlink on station 14 W Sep 28 (271) Ahead: 480 kbps downlink on station 14 Behind: 480 kbps downlink on station 14 T Sep 29 (272) Ahead: 480 kbps downlink on station 14 F Sep 30 (273) Behind: 480 kbps downlink on station 63 S Oct 01 (274) Behind: 480 kbps downlink on station 63 S Oct 02 (275) ------------------------------------------------------------------------------- Scheduled activities for Week 40: M Oct 03 (276) Ahead: 480 kbps downlink on station 63 Behind: 480 kbps downlink on station 63 T Oct 04 (277) Momentum dumps, Ahead: 13:30, Behind: 15:00 Ahead: 480 kbps downlink on station 63 W Oct 05 (278) Behind: 480 kbps downlink on station 14 T Oct 06 (279) Ahead: 480 kbps downlink on stations 14 and 43 F Oct 07 (280) S Oct 08 (281) Ahead: 480 kbps downlink on station 14 S Oct 09 (282) Ahead: 480 kbps downlink on station 63 Behind: 480 kbps downlink on station 14 ------------------------------------------------------------------------------- Scheduled activities for Week 41: M Oct 10 (283) Ahead: 480 kbps downlink on station 63 T Oct 11 (284) Behind: 480 kbps downlink on stations 14 and 63 W Oct 12 (285) Behind: 480 kbps downlink on station 14 T Oct 13 (286) Ahead: 480 kbps downlink on station 14 F Oct 14 (287) Ahead: 480 kbps downlink on station 63 S Oct 15 (288) Ahead: 480 kbps downlink on station 43 Behind: 480 kbps downlink on stations 43 and 14 S Oct 16 (289) Ahead: 480 kbps downlink on stations 63 and 43 Behind: 480 kbps downlink on station 43 ------------------------------------------------------------------------------- Upcoming events: 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: * Jan 20 Behind: End use of 480 kbps on 70 m DSN subnet * Apr 21 Behind: Resume use of 480 kbps on 70 m DSN subnet * Apr 29 Behind: Mercury transit * Oct 15 Behind: End use of 480 kbps on 70 m DSN subnet 2015: * Feb DAWN - Ceres arrival * Jan 20 - Mar 28 (TBC) Behind: Spacecraft behind Sun * Mar 17 - Jul 14 (TBC) Ahead: Spacecraft behind Sun * Jul 2 Behind: Resume use of 480 kbps on 70 m DSN subnet * Aug 25 - Oct 19 (TBC) Behind: Spacecraft behind Sun * Sep 25 Behind: End use of 480 kbps on 70 m DSN subnet * Jul DAWN - End of nominal mission 2016: * Apr 3 Behind: Resume use of 480 kbps on 70 m DSN subnet 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