STEREO Weekly Meeting Minutes for 2011-05-10 (Week 19) ANNOUNCEMENTS ------------- * None. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * All subsystems on both spacecraft are nominal. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 18 * On day 122 (May 2), during the DSS 14 support for Ahead, the antenna was red before the scheduled BOT at 1205z due to a software communications anomaly. The problem was resolved and telemetry was received at 1349z. The SSR playback was stopped and SSR pointers were repositioned. This anomaly caused the SECCHI SSR1 partition to fill on DOY 124 and resulted in the loss of two hours of SECCHI SSR data. See DR# G111438 for more information. * On day 128 (May 8), during the DSS 14 support for Ahead, initial telemetry lock at BOT was delayed 30 minutes due to the antenna pointing model. After a conscan was initiated telemetry lock occurred at 1225z. The SSR playback was stopped and SSR pointers were repositioned. All SSR data were recovered. See DR# G111463 for more information. * The 17th SECCHI stepped calibration rolls were carried out on both spacecraft on day 123 (May 3). These were the perihelion rolls. The actual dates of perihelion were day 118 (Apr 28) for Ahead, and day 119 (Apr 29) for Behind--the rolls were shifted to May 3 due to system momentum. * On day 125 (May 5), the MOps permanent macro release 1.1.9 was loaded to C&DH RAM on both spacecraft. This release supports changes for the SECCHI SSR2 partition playback. * On day 125 (May 5), the playback of SECCHI SSR2, special event partition #20, was enabled on Ahead at 1946z to test the modified playback CONOPs. * On day 123 (May 3), during the DSS 15 support for Behind, the maser receiver failed at the BOT. The station switched to the HEMT receiver to acquire telemetry lock. This resulted in the ranging data being calibrated after the track. All SSR data were recovered. See DR# G111445 for more information. * On day 124 (May 4), during the DSS 65 support for Behind, turbo decoder lock was lost briefly beginning at 2102z. This resulted in the loss of two frames of instrument SSR data. * On day 126 (May 6), during the DSS 65 support for Behind, telemetry lock was intermittently lost beginning at 1748z through 1922z due to heavy rain at Madrid. The SSR playback was stopped and SSR pointers were repositioned. This anomaly resulted in the loss of several minutes of instrument SSR data. See DR# M106314 for more information. * On day 127 (May 7), during the DSS 15 support for Behind, initial telemetry lock at BOT was delayed 7 minutes due to a data server failure at Goldstone. After the redundant data server was placed on-line, telemetry lock occurred at 0047z. This anomaly resulted in the loss of seven minutes of real-time data. All SSR data were recovered. See DR# G111456 for more information. * On day 123 (May 3), the playback of SECCHI SSR2, special event partition #20, was disabled on Behind at 1835z after playing back the recorded data. The playback was re-enabled at 124-1909z to test the modified playback CONOPs. * On day 124 (May 4), the SECCHI instrument on Behind reset at 16:14:56z. The SECCHI team reconfigured the instrument to operational mode at 1949z. This was the 15th reset of SECCHI on the Behind spacecraft. * On day 125 (May 5), IMPACT loaded new tables to the SIT instrument on Behind. * The average daily SSR downlink volume was 5.2 gigabits on Ahead, and 5.1 gigabits on Behind. Week 19 * There was a return-to-service track for station 24 for Ahead yesterday (May 9). This also served as a shadow track testing SLE telemetry. There will also be an SLE shadow track for Behind next week on Wednesday, May 18 using station 63. * Station 26 lost power briefly during the Behind pass late Sunday/early Monday (May 8-9). This caused the antenna brakes to trip. Power was quickly restored, and the antenna was brought back online. This resulted in the loss of 1-2 minutes of data. * Ahead has a 720 kbps pass on Tuesday, May 10, using station 63, and Sunday, May 15, using station D14. There are 14 passes during the week, and overall coverage is nominal. * Behind has 720 kbps passes on Monday, May 9, Tuesday, May 10, Wednesday, May 11, Thursday, May 12, Saturday, May 14, and Sunday, May 15, all using station D63 for a total of six 70 meter passes. There are 14 passes during the week, and overall coverage is 1.6 hours above nominal. Week 20 * The MOps macros 1.1.9 will be copied from RAM to EEPROM on May 17 for Ahead, and May 18 for Behind. * There will be a shadow track for Behind using station 63 on Wednesday, May 18 to test SLE telemetry, shadowing station 55. * Ahead has a 720 kbps pass on Wednesday, May 18 (D63), Thursday, May 19 (D43), and Sunday, May 22 (D14). There are 12 passes during the week, and overall coverage is nominal. * Behind has 720 kbps passes on Monday, May 16 (D63), Thursday, May 19 (D63), and Sunday, May 22 (D43), for a total of three 70 meter passes. There are 14 passes during the week, and overall coverage is 1.75 hours above nominal. Week 21 * Track changes have occured during the week in support of the upcoming Juno launch. * Ahead has 720 kbps passes on Thursday, May 26 (D43 and D43), and Sunday, May 29 (D63). There are 13 passes during the week, and overall coverage is 2.3 hours above nominal. * Behind has a 720 kbps pass on Saturday, May 28, using station D63. There are 12 passes during the week, and overall coverage is 6 hours above nominal. Week 22 * Monday, May 30 is Memorial day, which is a holiday at APL. * In preparation for switching to the 160 kbps downlink rate in late June, early July, the DSN time will be increased to 8 hours/day on both spacecraft. * 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. * The 32nd momentum dump on Behind will be carried out May 31, with ignition at 16:00 UT. * The 38th momentum dump on Ahead will be carried out Jun 1, with ignition at 14:30 UT. * Ahead has 720 kbps passes on Monday, May 30 (D14 and D43), Thursday, Jun 2 (D14 and D43), and Friday, Jun 3 (D63). There are 13 passes during the week, and overall coverage is nominal. * Behind has 720 kbsp passes on Tuesday, May 31 (D63), Wednesday, Jun 1 (D63), Thursday, Jun 2 (D63), Friday, Jun 3 (D63), Saturday, Jun 4 (D63), and Sunday, Jun 5 (D43). There are 10 passes during the week, and overall coverage is nominal. Week 23 * The IONET switches at APL will be upgraded. The backup switch will be upgraded on Jun 6 between 13-16 UT, which is during a track. This should not have an effect. The primary switch will be upgraded on Jun 8 between the Ahead pass ending at 14:45 UT, and the Behind pass starting at 16:50 UT. * Ahead has 720 kbps passes on Monday, Jun 6 (D14), Wednesday, Jun 8 (D63), Thursday, Jun 9 (D63), and Sunday, Jun 12 (D43). There are 12 passes during the week, and overall coverage is nominal. * Behind has 720 kbps passes on Monday, Jun 6 (D63), Tuesday, Jun 7 (D63), Friday, Jun 10 (D63), Saturday, Jun 11 (D63), and Sunday, Jun 12 (D43). There are 14 passes during the week, and overall coverage is nominal. Week 24 * 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. * Ahead has 720 kbps passes on Monday, Jun 13 (D63), Tuesday, Jun 14 (D63 and D14), Wednesday, Jun 15 (D63), and Thursday, Jun 16 (D63 and D43). There are 12 passes during the week, and overall coverage is 1.8 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 1.6 hours above nominal. Week 25 * 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. Other * SECCHI asked if there were any plans to do test tracks for the upcoming 160 kbps downlink rate. This rate was built into the system and was tested on the ground, so there won't be any test tracks. * PLASTIC noted there they saw a 1553 bus error yesterday (May 9) on Behind. IMPACT noted this error, but doesn't think there is anything to worry about. SWAVES will look into whether they also see a bus error. * A question was raised about when momentum wheel zero crossings occur. Zero crossings occured very early in the mission, but are now avoided. Wheel speeds are in the converted housekeeping data. Low wheel speeds generally occur about three weeks after momentum dumps. The question was raised whether the wheels use gas bearings, but the answer was not immediately available. Flight dynamics sees that the spacecraft becomes more reflective after momentum dumps, presumably because dust is knocked off the thermal blankets. They theorize that the same effect might occur during periods of increased jitter. SECCHI asks whether this increased reflectivity might also be responsible for periodic changes in temperature that they're seeing--however, APL reports that this is due to the way the heaters operate. COORDINATED OBSERVATIONS ------------------------ ------------------------------------------------------------------------------- Scheduled activities for Week 19: M May 09 (129) Ahead: Return-to-service track on station D24 Behind: 720 kbps downlink on station 63 T May 10 (130) Ahead: 720 kbps downlink on station 63 Behind: 720 kbps downlink on station 63 W May 11 (131) Behind: 720 kbps downlink on station 63 T May 12 (132) Behind: 720 kbps downlink on station 63 F May 13 (133) S May 14 (134) Behind: 720 kbps downlink on station 63 S May 15 (135) Ahead: 720 kbps downlink on station 14 Behind: 720 kbps downlink on station 63 ------------------------------------------------------------------------------- Scheduled activities for Week 20: M May 16 (136) Behind: 720 kbps downlink on station 63 T May 17 (137) W May 18 (138) Ahead: 720 kbps downlink on station 63 Behind: SLE testing on station 63, shadowing 55 T May 19 (139) Ahead: 720 kbps downlink on station 43 Behind: 720 kbps downlink on station 63 F May 20 (140) S May 21 (141) S May 22 (142) Ahead: 720 kbps downlink on station 14 Behind: 720 kbps downlink on station 43 ------------------------------------------------------------------------------- Scheduled activities for Week 21: M May 23 (143) T May 24 (144) W May 25 (145) T May 26 (146) Ahead: 720 kbps downlink on station 43 F May 27 (147) S May 28 (148) Behind: 720 kbps downlink on station 63 S May 29 (149) Ahead: 720 kbps downlink on station 63 ------------------------------------------------------------------------------- Scheduled activities for Week 22: M May 30 (150) Memorial Day Ahead: 720 kbps downlink on stations 14 and 43 T May 31 (151) Behind: 720 kbps downlink on station 63 Behind: Momentum dump, 16:00 UT W Jun 01 (152) Ahead: Momentum dump, 14:30 UT Behind: 720 kbps downlink on station 63 T Jun 02 (153) Ahead: 720 kbps downlink on stations 14 and 43 Behind: 720 kbps downlink on station 63 F Jun 03 (154) Ahead: 720 kbps downlink on station 63 Behind: 720 kbps downlink on station 63 S Jun 04 (155) Behind: 720 kbps downlink on station 63 S Jun 05 (156) Behind: 720 kbps downlink on station 43 Notes: * Changing to 8 hours/day of downlink on both spacecraft in preparation for switching to 160 kbps downlink rate in late June, early July. ------------------------------------------------------------------------------- Scheduled activities for Week 23: M Jun 06 (157) Ahead: 720 kbps downlink on station 14 Behind: 720 kbps downlink on station 63 T Jun 07 (158) Behind: 720 kbps downlink on station 63 W Jun 08 (159) Ahead: 720 kbps downlink on station 63 T Jun 09 (160) Ahead: 720 kbps downlink on station 63 F Jun 10 (161) Behind: 720 kbps downlink on station 63 S Jun 11 (162) Behind: 720 kbps downlink on station 63 S Jun 12 (163) Ahead: 720 kbps downlink on station 43 Behind: 720 kbps downlink on station 43 ------------------------------------------------------------------------------- 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 Behind: 720 kbps downlink on station 63 T Jun 16 (167) Ahead: 720 kbps downlink on station 63 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 ------------------------------------------------------------------------------- Upcoming events: 2011: * Jun 27 Ahead: Switch downlink rate to 160 kbps * Jun 27 Ahead: End use of 720 kbps on 70 m DSN subnet * Jul 15 Behind: Switch downlink rate to 160 kbps * Jul 15 Behind: End use of 720 kbps on 70 m DSN subnet * Jul 25 Behind: Close approach by comet Elenin * 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: * 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