STEREO Weekly Meeting Minutes for 2011-06-14 (Week 24) ANNOUNCEMENTS ------------- * None INSTRUMENT and SPACECRAFT STATUS -------------------------------- * All subsystems on both spacecraft are nominal. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 23 * On day 157 (June 6), during the DSS 14 support for Ahead, initial telemetry acquisition was delayed 18 minutes due to an antenna pointing model problem. After entering an elevation offset and switching to conscanning, telemetry lock was established at 11:43 UT. The SSR playback was stopped and SSR pointers were repositioned. All SSR data was recovered. * Also on day 157 (June 6), the transmitter was declared red before the start of the DSS 45 support for Ahead. At 21:45 UT DSS 43 was added for an hour to provide an uplink for IMPACT LET real-time diagnostic commanding. Several minutes of instrument SSR data were lost when the uplink was terminated. * On day 157, during the DSS 63 support for Behind telemetry lock was intermittent beginning at 16:53 UT for 46 minutes due to rain in Madrid. A stable telemetry lock was established at 17:39 UT. The SSR playback was stopped and SSR pointers were repositioned. All SSR data was recovered. * On day 158 (June 7), during the DSS 65 support for Ahead, real-time telemetry was lost intermittently 10:21 through 10:49 UT due to adverse weather conditions at Madrid. This resulted in the loss of several minutes SSR data. * The IMPACT/LET instrument was rebooted and 2007 threshold levels were loaded on Ahead on day 159 (June 8) at 12:27 UT and on Behind on day 160 (June 9) at 19:18 UT. Both instruments had stopped collecting data, Ahead on day 155 and Behind on day 151. * On day 159 (June 8), during the DSS 65 support,real-time telemetry for Behind was lost beginning at 18:00 UT through 18:33 UT due to a power outage at the Madrid complex which affected the network connectivity. This resulted in the loss of 160 frames of instrument SSR data. * On day 161 (June 10), DSS 14 was declared red before BOT and the support for Ahead was switched to DSS 26 for its entirety. Initial telemetry acquisition was delayed 34 minutes as the downlink rate was decreased from 720 kbps for the planned 70m use to 240 kbps for the 34m antenna. The SSR playback was stopped and SSR pointers were repositioned. All SSR data was recovered. * On day 161 (June 10), during the DSS 63 support for Behind, turbo decoder lock was lost briefly beginning at 19:40 UT and 20:33 UT. This resulted in the loss of nine frames of instrument SSR data. * On day 163 (June 12), during the DSS 54 support for Ahead, turbo decoder lock was lost briefly at 06:17 UT. This resulted in the loss of one frame of instrument SSR data. * On day 163 (June 12), during the DSS 26 support for Behind, turbo decoder lock was lost briefly at 22:51 UT. This resulted in the loss of four frames of instrument SSR data. * The average daily SSR play back volume this week was 5.7 Gbits for Ahead and 5.9 Gbits for Behind. Week 24 (June 13-19) * On day 164 Jun 13 there was a brief loss of the turbo decoder lock for Behind. * There will be a 2 hour return-to-service track on station 34 for Ahead on Jun 14. There will be no SSR playback during this track. Uplink will be enabled. * There will be test of the 160 kbps downlink during the station 25 pass for Ahead on Wednesday, Jun 15, 12:25 UT-16:43 UT. The prior pass will be a 70 meter station, and a long 70 meter pass follows the test, so no data will be lost. Since the in-situ teams are planning to drop their telemetry rates for 160 kbps, this can be tested during the Jun 15 pass, but this is not required. The telemetry rates will drop to 160 kbps on Jun 27 for Ahead, and Jul 13 for Behind. At the same time that the nominal telemetry rate drops to 160 kbps, the telemetry rate for the 70 meter stations will drop from 720 kbps to 480 kbps. * Ahead has 720 kbps passes on Monday, Jun 13 (D63), Tuesday, Jun 14 (D63 and D14), Wednesday, Jun 15 (D63), and Thursday, Jun 16 (D43). There are 12 passes during the week, and overall coverage is 4.2 hours above nominal. * Behind has 720 kbps passes on Monday, Jun 13, Tuesday, Jun 14, and Wednesday, Jun 15, all using station 63. There are 14 passes during the week, and overall coverage is 1.5 hours above nominal. Week 25 (June 20-26) * Macros for the 160 and 120 kbps downlink rates will be uploaded to RAM on both spacecraft on Tuesday, day 172 (Jun 21). * Ahead has a 720 kbps pass on Friday, Jun 24, using station 43. There are 11 tracks during the week, and overall coverage is 1.6 hours above nominal. * Behind has a 720 kbps pass on Sunday, Jun 26, using station 63. There are 13 tracks during the week, and overall coverage is 4.1 hours above nominal. Week 26 (June 27-July 3) * Ahead switches downlink rate to 160 kbps on 35 meter stations, and 480 kbps on 70 meter stations on day 178 (Jun 27), starting with the station 15 pass. 480 kbps is the lowest rate that Ahead is projected to use with 70 meter stations--Behind will drop to 360 kbps for periods near the far side. * Modified macros for the 240 kbps rate will be uploaded to RAM on both spacecraft on Monday, day 178 (Jun 27) to take advantage of the increasing OWLT. These changes will downlink the spacecraft housekeeping data prior to the uplink sweep for each pass. Science playback time will continue to start at nearly the same time as it currently does. These changes will increase the science data return by about 20 minutes since the playback of spacecraft data is currently after the uplink sweep. Weekly schedules do not currently reflect this, but new versions will be out by the end of the week. * Ahead has 480 kbps passes on Thursday, Jun 30 (D63), and Sunday, Jul 3 (D43). There are 9 passes during the week, and overall coverage is nominal. * Behind has 720 kbps passes on Monday, Jun 27, Wednesday, Jun 29, Thursday, Jun 30, Friday, Jul 1, and Saturday, Jul 2, all using station 63. There are 12 passes during the week, and overall coverage is nominal. Week 27 (July 4-10) * Monday, July 4 is a holiday, so if you need to command please contact the MOC ahead of time. * Switch over to Space Link Extension (SLE) protocol on Behind July 5 during DSS 63 track and on Ahead July 6 during DSS 14 track. Both the switches will take place during business hours. * Ahead has 480 kbps passes on Tuesday, Jul 5 (D63 and D14), Wednesday, Jul 6 (D63 and D14), Thursday, Jul 7 (D14), and Friday, Jul 8 (D63). There are 13 passes during the week, and overall coverage is nominal. * Behind has 720 kbps passes on Tuesday, Jul 5 (D63), Friday, Jul 8 (D43), and Sunday, Jul 10 (D63). There are 12 passes during the week, and overall coverage is nominal. Week 28 * Behind will switch to the 160 kbps rate for 35 meter stations, and 480 kbps for 70 meter stations, starting with the station 55 pass on Jul 13. * Both spacecraft will have an HGA calibration on Jul 13, with Ahead starting at 15:00 UT, and Behind starting at 16:00 UT. * Behind will have the 33rd momentum dump on Tuesday, Jul 12, starting at 19:30 UT. * Ahead will have the 39th momentum dump on Thursday, Jul 14, starting at 15:00 UT. * Ahead has 480 kbps passes on Tuesday, Jul 12, and Saturday, Jul 16, both using station 43. There are 10 passes during the week, and overall coverage is 3.6 hours above nominal. * Behind has 720 kbps passes on Tuesday, Jul 12 (D43 and D63), and 480 kbps passes on Thursday, Jul 14 (D43), Friday, Jul 15 (D43 and D63), and Sunday, Jul 17 (D43). There are 15 passes during the week, and overall coverage is 4.1 hours above nominal. Other * APL has received the SECCHI team request to roll the Behind spacecraft by 135 degrees for two hours per day each day between Aug 1 (or late on July 31) and Aug 12 to observe comet Elenin as it flies within 0.05 AU of the spacecraft. Observations of the comet at a wide variety of phase angles will provide information about composition. There's also a possibility that the in situ instruments on Behind will see the ion tail. The requested two hours per day will include the roll and settle times, with the roll starting on an even hour boundary, and then back to nominal roll and settled on the next even hour boundary. APL will test the maneuver on the hardware simulator and will also want to test it on the spacecraft about two weeks before the actual observations. COORDINATED OBSERVATIONS ------------------------ ------------------------------------------------------------------------------- Scheduled activities for Week 24: M Jun 13 (164) Ahead: 720 kbps downlink on station 63 Behind: 720 kbps downlink on station 63 T Jun 14 (165) Ahead: 720 kbps downlink on stations 63 and 14 Behind: 720 kbps downlink on station 63 Ahead: Return-to-service track on station 34 W Jun 15 (166) Ahead: 720 kbps downlink on station 63 Ahead: Test of 160 kbps on station 25 Behind: 720 kbps downlink on station 63 T Jun 16 (167) Ahead: 720 kbps downlink on station 43 F Jun 17 (168) S Jun 18 (169) S Jun 19 (170) ------------------------------------------------------------------------------- Scheduled activities for Week 25: M Jun 20 (171) T Jun 21 (172) W Jun 22 (173) T Jun 23 (174) F Jun 24 (175) Ahead: 720 kbps downlink on station 43 S Jun 25 (176) S Jun 26 (177) Behind: 720 kbps downlink on station 63 ------------------------------------------------------------------------------- Scheduled activities for Week 26: M Jun 27 (178) Ahead: Switch downlink rate to 160 kbps, 480 kbps for 70 m Behind: 720 kbps downlink on station 63 T Jun 28 (179) W Jun 29 (180) Behind: 720 kbps downlink on station 63 T Jun 30 (181) Ahead: 480 kbps downlink on station 63 Behind: 720 kbps downlink on station 63 F Jul 01 (182) Behind: 720 kbps downlink on station 63 S Jul 02 (183) Behind: 720 kbps downlink on station 63 S Jul 03 (184) Ahead: 480 kbps downlink on station 43 ------------------------------------------------------------------------------- Scheduled activities for Week 27: M Jul 04 (185) Independence day T Jul 05 (186) Ahead: 480 kbps downlink on stations 63 and 14 Behind: 720 kbps downlink on station 63 W Jul 06 (187) Ahead: 480 kbps downlink on stations 63 and 14 T Jul 07 (188) Ahead: 480 kbps downlink on station 14 F Jul 08 (189) Ahead: 480 kbps downlink on station 63 Behind: 720 kbps downlink on station 43 S Jul 09 (190) S Jul 10 (191) Behind: 720 kbps downlink on station 63 ------------------------------------------------------------------------------- Scheduled activities for Week 28: M Jul 11 (192) T Jul 12 (193) Behind: Momentum dump, 19:30 UT Ahead: 480 kbps downlink on station 43 Behind: 720 kbps downlink on stations 43 and 63 W Jul 13 (194) Behind: Switch downlink rate to 160 kbps, 480 kbps for 70 m HGA calibration, Ahead: 15:00 UT, Behind: 16:00 UT T Jul 14 (195) Ahead: Momentum dump, 15:00 UT Behind: 480 kbps downlink on station 43 F Jul 15 (196) Behind: 480 kbps downlink on stations 43 and 63 S Jul 16 (197) Ahead: 480 kbps downlink on station 43 S Jul 17 (198) Behind: 480 kbps downlink on station 43 Notes: * Dawn expected to achieve orbit about Vesta around Jul 16. ------------------------------------------------------------------------------- Upcoming events: 2011: * Jul 31 - Aug 12 Behind: Spacecraft rolls to observe comet Elenin 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