STEREO Weekly Meeting Minutes for 2011-08-30 (Week 35) ANNOUNCEMENTS ------------- * None INSTRUMENT and SPACECRAFT STATUS -------------------------------- * All subsystems on both spacecraft are nominal. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 34 (Aug 22-28) * An earthquake occurred on Tuesday, Aug 23, and Hurricane Irene passed through the area during Aug 27-28. Both of these events required action or preparation by the MOC. * On day 234 (Aug 22), during the DSS 63 support for Ahead, turbo decoder lock was lost briefly beginning at 1101z. This resulted in the loss of eight frames of SSR data. See DR# N107549 for more information. * On day 235 (Aug 23), during the DSS 55 support for Ahead, telemetry lock was lost at 1441z due to subreflector drive anomaly. The subreflector drive was reset and telemetry lock was reestablished at 1449z. This resulted in the loss of several minutes of SSR data. See DR# M106445 for more information. * On day 236 (Aug 24), the MOC was notified that the DSS 14 antenna was red due to an azimuth pointing anomaly. The Ahead support was switched to use DSS 15 with a duration of 2.8 hours. The Ahead S/C was re-configured to downlink at the lower 160 kbps data rate as the supports were switched from a 70 meter to a 34 meter station. As there was insufficient track time, the planned momentum dump was postponed and re-planned to occur the next day with ignition at 237-1230z. To minimize science data loss, the day 238 (Aug 26) 70m support with DSS 63 was switched to downlink at the higher 720 kbps as its elevation was above 25 degrees for the duration of the support. This worked well, with a 4 dB or better margin throughout the pass, and the recorder was emptied. As a result of insufficient track time, the IMPACT and SWAVES science partitions and the SECCHI synoptic science partition are anticipated to have lost 10 to 14 hours of science data each on days 237 and 238 (Aug 25-26) as follows. No data loss was apparent for PLASTIC. See DR# G111907 for more information. IMPACT partition 15 was > 95%: 237-061254z/100913z (3:56:19) 237-185053z/205513z (2:04:20) 238-045133z/084753z (3:56:20) Total = 9:56:59 SECCHI partition 19 was at 100%: 237-001314z/100913z (9:55:59) 237-101813z/101913z (0:01:00) 237-183613z/205513z (2:19:00) 238-063633z/084753z (2:11:20) Total = 14:27:19 SWAVES partition 13 was at 100%: 237-043954z/100913z (5:29:19) 237-101713z/101913z (0:02:00) 237-191633z/205513z (1:39:00) 237-210213z/210513z (0:03:00) 238-050833z/084753z (3:39:20) Total = 10:52:39 * SWAVES reports that there was no actual data loss during this period. * On day 240 (Aug 28), during the DSS 15 support, turbo decoder lock was lost briefly beginning at 2250z. This resulted in the loss of one frame of SSR data. A DR has been requested. * On day 237 (Aug 25), the 40th momentum dump on Ahead was successfully executed at 1230Z, which imparted a delta V of 0.0866 m/sec. * On day 235 (Aug 23), during the DSS 34 support for Behind, turbo decoder lock was lost briefly beginning at 0659z and again at 0733z. This resulted in the loss of two frames of SSR data. See DR# N107551 for more information. * On day 235 (Aug 23), during the DSS 65 support for Behind, turbo decoder lock was lost briefly beginning at 1819z and again at 1847z. This resulted in the loss of nine frames of SSR data. See DR# N107552 for more information. * On day 237 (Aug 25), during the DSS 24 support for Behind, turbo decoder lock was lost briefly beginning at 0215z. This resulted in the loss of 15 frames of SSR data. A DR has been requested. * On day 239 (Aug 27), during the DSS 26 support for Behind, initial telemetry acquisition was delayed five minutes due to station reconfiguration arising from electrical power restoration activities. Telemetry lock was established at 0100z. Later in the support, real-time telemetry was lost at 0208z due to a DCD anomaly. Currently several hours of data are missing from day 238 for which the DSN is investigating. See DR# G111913 and G111914 for more information. * On day 240 (Aug 28), during the DSS 65 support for Behind, turbo decoder lock was lost briefly beginning at 1245z and again at 1744z. This resulted in the loss of 77 frames of SSR data. A DR has been requested. * On day 236 (Aug 24), the 34th momentum dump on Behind was successfully executed at 1800Z, which imparted a delta V of 0.0644 m/sec. * The average daily SSR downlink volume was 4.1 gigabits for Ahead, and 4.5 gigabits for Behind. * An IDR was not delivered for the Ahead spacecraft for Tuesday, day 235 (Aug 23). The missing data were requested, and New telemetry files for day 235 were generated this morning (Aug 30). Week 35 (Aug 29-Sep 4) * Turbo decoder lock was lost briefly yesterday (Aug 29) at 07:50 during the station 63 pass for Ahead. Some packets were lost. * 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 was tested on the Behind spacecraft on Monday, Aug 29. The 70 meter station 43 pass on that day was conducted at 720 kbps. The margin was 4 dB or better throughout the pass. This procedure was also successfully tested on Ahead on Friday, Aug 26. Tests on 34 meter stations will be scheduled. Regular use of these rates needs CCB approval. These rates will be reflected in the weekly schedules. * 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 a 720 kbps pass on Monday Aug 29 using station 43, and 480 kbps passes on Monday, Aug 29 (D63), 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 12 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 will need to be reestablished after the upgrade. * 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 11 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 11 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. Week 42 (Oct 17-23) * Ahead has a 480 kbps pass on Monday, Oct 17 using station 14. There are 9 passes during the week, and overall coverage is nominal. * Behind has a 480 kbps pass on Thursday, Oct 20, using station 14. There are 13 passes during the week, and coverage is short 1.5 hours on Friday, Oct 21. Week 43 (Oct 24-30) * The 19th SECCHI stepped calibration roll will be carried out on Ahead on Wednesday, Oct 26, starting at 08:25 UT. This will be the aphelion roll. The actual date of aphelion is day 290 (Oct 17). System momentum will be about 3 N-m-s. * Ahead has 480 kbps passes on Monday, Oct 24 (D63), Tuesday, Oct 25 (D14), and Wednesday, Oct 26 (D14). There are 9 passes during the week, and overall coverage is nominal. * Behind has a 480 kbps pass on Wednesday, Oct 26 using station 63. There are 12 passes during the week, and coverage is short 1.2 hours on Monday, Oct 24. Week 44 (Oct 31-Nov 6) * Daylight savings time is ending in the U.S. on Nov 6 at 06:00 UT. * Ahead has 480 kbps passes on Monday, Oct 31 (D14), Tuesday, Nov 1 (D14), Wednesday, Nov 2 (D63), and Saturday, Nov 5 (D43). There are 10 tracks during the week, and coverage is short 1.25 hours on Nov 6. * Behind has 480 kbps passes on Wednsday, Nov 2 (D63), and Saturday, Nov 5 (D43 and D63). There are 12 passes during the week, and coverage is short 1.4 hours between Monday and Tuesday (Oct 31-Nov 1). Other * NASA headquarters is considering using ESA stations for either STEREO or GRAIL to ease DSN contentions. COORDINATED OBSERVATIONS ------------------------ ------------------------------------------------------------------------------- Scheduled activities for Week 35: M Aug 29 (241) Ahead: 480 kbps downlink on station 63 Behind: 720 kbps downlink on station 43 Behind: 480 kbps downlink on station 63 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 ------------------------------------------------------------------------------- Scheduled activities for Week 42: M Oct 17 (290) Ahead: 480 kbps downlink on station 14 T Oct 18 (291) W Oct 19 (292) T Oct 20 (293) Behind: 480 kbps downlink on station 14 F Oct 21 (294) S Oct 22 (295) S Oct 23 (296) ------------------------------------------------------------------------------- Scheduled activities for Week 43: M Oct 24 (297) Ahead: 480 kbps downlink on station 63 T Oct 25 (298) Ahead: 480 kbps downlink on station 14 W Oct 26 (299) Ahead: SECCHI stepped calibration roll, 8:25 UT Ahead: 480 kbps downlink on station 14 Behind: 480 kbps downlink on station 63 T Oct 27 (300) F Oct 28 (301) S Oct 29 (302) S Oct 30 (303) ------------------------------------------------------------------------------- Scheduled activities for Week 44: M Oct 31 (304) Ahead: 480 kbps downlink on station 14 T Nov 01 (305) Ahead: 480 kbps downlink on station 14 W Nov 02 (306) Ahead: 480 kbps downlink on station 63 Behind: 480 kbps downlink on station 63 T Nov 03 (307) F Nov 04 (308) S Nov 05 (309) Ahead: 480 kbps downlink on station 43 Behind: 480 kbps downlink on stations 43 and 63 S Nov 06 (310) Daylight savings time ends in USA ------------------------------------------------------------------------------- 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