STEREO Weekly Meeting Minutes for 2011-05-17 (Week 20) ANNOUNCEMENTS ------------- * None. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * All subsystems on both spacecraft are nominal, except for an interference pattern which has appeared on some of the SECCHI-Behind telescopes, as discussed below. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 19 * On day 129 (May 9), CCSDS SLE telemetry testing using DSS 24 as a shadow track for Ahead was conducted successfully in parallel with the DSS 15 committed track. This was also a return-to-service track for station 24. * On day 132 (May 12), during the DSS 55 support for Ahead, turbo decoder lock was lost briefly beginning at 0700z. This resulted in the loss of one frame of SECCHI SSR data. See DR# N107312 for more information. * On day 133 (May 13), during the DSS 54 support for Ahead, turbo decoder lock was lost briefly beginning at 0655z. This resulted in the loss of two frames of instrument SSR data. See DR# N107313 for more information. * On day 133 (May 13), the RAID array controller for the MOC STEREO Data Server workstation failed at 1200z. The workstation was rebooted to use the mirrored RAID array at 1600z. The MOC sent out a notice that commands submitted between 1 A.M. and noon local time would have been lost. Since no instrument teams responded, it is assumed that no instruments were affected. * On day 135 (May 15), during the DSS 14 support for Ahead, real-time telemetry was lost in the MOC starting at 1943z for the duration of 54 minutes due to a DCD anomaly. The anomaly was corrected at 2037z. This resulted in the loss of 54 minutes of real-time telemetry data. All SSR data were recovered. See DR# N107318 for more information. * On day 129 (May 9), during the DSS 26 support for Behind, telemetry lock was lost at 0214z due to power glitch at the station that caused the antenna brakes to be set. After electrical power was restored, telemetry lock was re-established at 0215z. This anomaly resulted in the loss of several minutes of instrument SSR data. See DR# G111467 for more information. * On day 131 (May 11), during the DSS 25 support for Behind, real-time telemetry was not received in the MOC for the duration of the track due to a DCD anomaly. This resulted in the loss of 180 minutes of all tracking data and real-time telemetry data. All SSR data were recovered from DSN FDS server. See DR# G111478 for more information. * On day 131 (May 11), during the DSS 63 support for Behind, turbo decoder lock was lost briefly beginning at 1930z. This resulted in the loss of seven frames of instrument SSR data. See DR# N107314 for more information. * On day 132 (May 12), during the DSS 63 support for Behind, turbo decoder lock was lost briefly beginning at 1948z. This resulted in the loss of one frame of instrument SSR data. See DR# N107315 for more information. * On day 133 (May 13), during the DSS 45 support for Behind, turbo decoder lock was lost briefly beginning at 0620z. This resulted in the loss of 217 frames of instrument SSR data. See DR# N107316 for more information. * On day 134 (May 14), during the DSS 63 support for Behind, telemetry lock was intermittently lost beginning at 1614z through 1618z due to heavy rain at Madrid. This anomaly resulted in the loss of several minutes of instrument SSR data. See DR# N107319 for more information. * On day 134 (May 14), during the DSS 25 support for Behind, telemetry lock was lost beginning at 2356z through 135-0013z due to antenna brakes being set. This anomaly resulted in the loss of several minutes of instrument SSR data. See DR# G111486 for more information. * On day 129 (May 9), the SECCHI BEHIND COR1, COR2, and EUVI images began showing an interference pattern at 1720z. The SECCHI and MOC teams are investigating. IMPACT/PLASTIC and SWAVES saw a 1553 bus error at about the same time. The coincidence of the timing is suggestive, but the relationship is not understood. Currently, the theory is that the problem is caused by an SEU in one of the memory chips. The HI telescopes do not show any problem. They have a separate CEB from the COR1/COR2/EUVI telescopes. SECCHI tried cycling power on the CEB on Thursday, May 12. This affected the interface pattern, but did not make it go away completely. After cycling the CEB power the pattern became steady, whereas before it was variable. SECCHI tried a warm reboot of the entire instrument yesterday (May 16), but this had no effect. They will take some diagnostic images to try to understand the problem better, and then try cycling power on the entire instrument. This procedure should be similar to that done when updating the spacecraft ACS software. Coordination with the MOC is needed to get the instrument turned back on. NRL and APL will arrange a time to do this, possibly tomorrow (May 18). * The average daily SSR downlink volume was 5.2 gigabits for Ahead, and 6.1 gigabits for Behind. Week 20 * Uplink was late for the station 25 pass for Ahead yesterday (May 16). Pointers were moved, and no data should be lost. * The MOps macros 1.1.9 were copied from RAM to EEPROM on Ahead this morning (May 17). The same will be done on Behind tomorrow (May 18). * There will be a shadow track for Behind using station 63 on Wednesday, May 18 to test SLE telemetry, shadowing station 55. Assuming this goes successfully, APL will arrange with DSN when to switch over to SLE, sometime in the next few weeks. There are some final changes that need to be made to operations scripts for unattended mode, and they want to watch the first track on each spacecraft to make sure no problems arise. * Station 14 is back on encoder mode, without the pointing model. This means that problems can be anticipated at low elevation angles. * 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 * 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. * 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), Friday, Jun 10 (D14), 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. Uplink will be enabled. * There will be test of the 160 kbps downlink during the station 25 pass for Ahead on Wednesday, Jun 15. 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 (D63 and D43). There are 12 passes during the week, and overall coverage is 2.8 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 1.5 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. COORDINATED OBSERVATIONS ------------------------ ------------------------------------------------------------------------------- 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) Ahead: 720 kbps downlink on station 14 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 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 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