STEREO Weekly Meeting Minutes for 2012-11-06 (Week 45) ANNOUNCEMENTS ------------- * Significant coverage shortfalls for the Behind spacecraft are expected starting during week 46 and continuing through the end of the year. See below for details. * It has been decided to routinely step up the telemetry rate for passes using DSN station 26 on both spacecraft to improve data return. See below for details. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * All subsystems on both spacecraft are nominal. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 44 (Oct 29-Nov 4) * On day 306 (Nov 1), during the DSS-55 support for Ahead, turbo decoder lock was lost briefly at 0753z. This anomaly resulted in the loss of one frame of SSR data. See DR# N108495 for more information. * On day 307 (Nov 2), during the DSS-55 support for Ahead, turbo decoder lock was lost briefly at 0741z. This anomaly resulted in the loss of one frame of SSR data. See DR# N108497 for more information. * On day 308 (Nov 3), during the DSS-63 support for Ahead, turbo decoder lock was lost intermittently beginning at 0555z through 0715z due to heavy rain. This anomaly resulted in the loss of several minutes (93148 frames) of SSR data. See DR# M106975 for more information. * On day 309 (Nov 4), during the DSS-63 support for Ahead, turbo decoder lock was lost intermittently beginning at 0652z through 0809z. This anomaly resulted in the loss of 1296 frames of SSR data. See DR# requested for more information. * On day 309 (Nov 4), during the DSS-15 support for Ahead, turbo decoder lock was lost briefly at 1624z. This anomaly resulted in the loss of one frame of SSR data. See DR# N108501 for more information. * On day 307 (Nov 2), the 51st momentum dump was executed successfully at 1630Z, which imparted a delta V of 0.096 m/sec. * On day 306 (Nov 1), during the DSS-63 support for Behind, turbo decoder lock was lost briefly at 1129z. This anomaly resulted in the loss of 26 frames of SSR data. See DR# N108496 for more information. * On day 308 (Nov 3), during the DSS 14 support for Behind, tracking, telemetry and ranging data was lost intermittently between 1933z and 2008z due to Hour Angle encoder glitch antenna alarms. This anomaly resulted in the loss of several minutes (14475 frames) of SSR data. See DR #G113354 for more information. * On day 303 (Oct 29), the SSR science partitions on Behind filled as follows: SWAVES (Part 13) reached 100% full at 1630z for 2.1 hours. IMPACT (Part 15) reached 95% full at 1823z for 0.2 hours. SECCHI (Part 19) reached 100% full at 1656z for 1.6 hours. The primary cause was the SSR pointer repositioning to minimize data loss during DSS-63 track with heavy rain on DOY 299 (Oct 25). * On day 305 (Oct 31), the SSR science partitions on Behind filled as follows: SWAVES (Part 13) reached 100% full at 2000z for 2.3 hours. The primary cause was the accumulated shortage of track time throughout the week. * On day 307 (Nov 2), the SSR science partitions on Behind filled as follows: SWAVES (Part 13) reached 100% full at 0647z for 15.5 hours. IMPACT (Part 15) reached 95% full at 1749z for 4.5 hours. The primary cause was the accumulated shortage of track time throughout the week. * On day 308 (Nov 3), the SECCHI instrument on Behind reset at 14:36:54z. The SECCHI team reconfigured the instrument to operational mode at 1920z. This was the 18th reset of SECCHI on the Behind spacecraft. * The average daily SSR playback volume during the week was 5.3 gigabits on Ahead, and 4.7 gigabits on Behind. * A question was raised about how close PLASTIC came to being full during the periods when the other instruments reached capacity. Exact numbers were not available, but it was thought that PLASTIC was 60-70% full during these times. * IMPACT dropped their telemetry rate on Oct 27. This rate drop was described as considerable. * APL was commended for revising the spacecraft operations schedule to work around Hurricane Sandy. People were working at APL on the Saturday and Sunday before the storm for rescheduled activities, and to prepare. Week 45 (Nov 5-11) * The nominal telemetry rate for Behind with 34 meter stations will drop from 160 kbps to 120 kbps starting Monday, Nov 5. The telemetry rate for high elevation passes will drop from 240 kbps to 160 kbps. The same change will be made for Ahead next spring. * The 46th momentum dump on Behind is scheduled for Tuesday, Nov 6, starting at 21:00 UT. * Ahead has 13 passes during the week, and overall coverage is nominal. There are 70 meter passes on Monday, Nov 5 (D63), Tuesday, Nov 6 (D14), Wednesday, Nov 7 (D14), Friday, Nov 9 (D63), and Saturday, Nov 10 (D63, D43 at 720 kbps). An ESA New Norcia pass is scheduled for Sunday, Nov 11. * Behind has 8 tracks during the week, and overall coverage is nominal. There are 70 meter passes on Monday, Nov 5 (D63), Tuesday, Nov 6 (D14), Wednesday, Nov 7 (D43 at 720 kbps), Thursday, Nov 8 (D63), Friday, Nov 9 (D63), Saturday, Nov 10 (D14), and Sunday, Nov 11 (D14). The station 34 pass on Friday, Nov 9, will be the first pass to be carried out at 120 kbps, and the only one scheduled during the week. Week 46 (Nov 12-18) * Monday, November 12 is Veterans Day. * Ahead has 14 passes during the week, and overall coverage is nominal. There are 70 meter passes on Tuesday, Nov 13, and Saturday, Nov 17, both using station D14. * Behind has 9 passes during the week, and overall coverage has a significant shortage of 16.3 hours over the course of the week. This is due to several stations going down for maintenance all at the same time. Station 43 will be down for six months. Station 54 will be down for about a month, and is expected to be back up on day 344 (Dec 9). The ESA New Norcia station will also be going down for maintenance. Coverage will be scant for the entire week, but will be particularly tight on Monday, Nov 12, and Thursday, Nov 15. 70 meter stations are scheduled for Tuesday, Nov 13 (D14), Thursday, Nov 15 (D63), Saturday, Nov 17 (D14), and Sunday, Nov 18 (D63). The station 24 pass on Monday, Nov 12, and the station 34 pass on Friday, Nov 17, will be carried out at 160 kbps. An ESA Cebreros pass is scheduled for Monday, Nov 12. Coverage shortfalls for Behind are expected to continue through the end of the year. Week 47 (Nov 19-25) * Thursday, Nov 22 is Thanksgiving. Both Thursday and Friday, Nov 22-23, are holidays at APL. * Ahead has 15 passes during the week, and overall coverage is nominal. 70 meter passes are scheduled for Monday, Nov 19, Wednesday, Nov 21, and Thursday, Nov 22, all using station 14. * Behind has 11 passes during the week, and coverage is short 11.3 hours. This is an improvement over the previous 18.2 hour shortage. The shortage covers day2 326-330 (Wednesday-Sunday, Nov 21-25). 70 meter passes are scheduled for Monday, Nov 19, Tuesday, Nov 20, and Saturday, Nov 24, all using station 63. Week 48 (Nov 26-Dec 2) * Behind reaches aphelion on day 337 (Dec 2). * Ahead has 13 passes during the week, and overall coverage is nominal. There are 70 meter passes on Monday, Nov 26 (D63), Tuesday, Nov 27 (D63), Thursday, Nov 29 (D14), and Saturday, Dec 1 (D63 at 720 kbps, D14). * Behind has 10 passes during the week, and overall coverage is short 11.4 hours. This coverage mainly affects days 333-336 (Nov 28-Dec 1). There are 70 meter passes on Monday, Nov 26, Tuesday, Nov 27, Friday, Nov 30, and Sunday, Dec 2, all using station 63. An ESA Cebreros pass is scheduled for Saturday, Dec 1. Week 49 (Dec 3-9) * The 52nd momentum dump on Ahead is scheduled for Thursday, Dec 6, with ignition at 16:45 UT. * The 23rd SECCHI stepped calibration roll on Behind is scheduled for Tuesday, Dec 4, starting at 08:15 UT. * The second annual battery discharge on Behind is scheduled for Tuesday, Dec 4, starting at 13:00 UT. * Ahead has 14 passes during the week, and overall coverage is nominal. There are 70 meter passes on Thursday, Dec 6 (D14), and Saturday, Dec 8 (D63). * Behind has 11 passes during the week, and overall coverage in nominal. There are 70 meter passes scheduled for Tuesday, Dec 4 (D63), Wednesday, Dec 5 (D63), Thursday, Dec 6 (D63), and Saturday, Dec 8 (D14 at 720 kbps). The station 45 pass on Friday, Dec 7, will be carried out at 160 kbps. Other * The RF link analysis for STEREO has been updated. Based on this analysis it has been determined that the link margin for DSN station 26 is significantly better than other 34 meter stations. Thus, it has been decided to routinely step up passes using station 26 to the next higher telemetry rate, e.g. from 120 kbps to 160 kbps, regardless of the elevation of the pass. If the entire pass is above 25 degrees then the rate will be stepped up again, e.g. from 160 kbps to 240 kbps. This change will be made for both spacecraft. * It was also suggested that stations 34 and 55 also show improved performance over other 34 meter station. The MOC will look into what improvements, if any, can be implemented with these stations. * The examination of the link margin, and operational planning, for the solar conjunction periods in 2015 will be addressed next year. COORDINATED OBSERVATIONS ------------------------ ------------------------------------------------------------------------------- Scheduled activities for Week 45: M Nov 05 (310) Behind: Switch downlink rate to 120 kbps T Nov 06 (311) Behind: Momentum dump, 21:00 UT W Nov 07 (312) T Nov 08 (313) F Nov 09 (314) S Nov 10 (315) S Nov 11 (316) ------------------------------------------------------------------------------- Scheduled activities for Week 46: M Nov 12 (317) Veterans Day T Nov 13 (318) Total solar eclipse, south Pacific W Nov 14 (319) T Nov 15 (320) F Nov 16 (321) S Nov 17 (322) S Nov 18 (323) ------------------------------------------------------------------------------- Scheduled activities for Week 47: M Nov 19 (324) T Nov 20 (325) W Nov 21 (326) T Nov 22 (327) Thanksgiving F Nov 23 (328) S Nov 24 (329) S Nov 25 (330) ------------------------------------------------------------------------------- Scheduled activities for Week 48: M Nov 26 (331) T Nov 27 (332) W Nov 28 (333) T Nov 29 (334) F Nov 30 (335) S Dec 01 (336) S Dec 02 (337) ------------------------------------------------------------------------------- Scheduled activities for Week 49: M Dec 03 (338) T Dec 04 (339) Behind: SECCHI stepped calibration roll, 08:15 UT W Dec 05 (340) T Dec 06 (341) Ahead: Momentum dump, 16:45 UT F Dec 07 (342) S Dec 08 (343) S Dec 09 (344) ------------------------------------------------------------------------------- Upcoming events: 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 * Jul Juno arrival at Jupiter 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