STEREO Weekly Meeting Minutes for 2013-01-07 (Week 02) ANNOUNCEMENTS ------------- * IMU-B on the STEREO Behind spacecraft suffered a failure on Jan 5. The spacecraft was switched back to IMU-A, and was recovered to operational mode on Jan 6. See below for details. * The HGA calibration for Behind scheduled for tomorrow, Jan 8, has been cancelled. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * See the discussion below about the IMU failure on STEREO Behind. Otherwise, all subsystems on both spacecraft are nominal. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 52 (Dec 23-29) * On day 358 (Dec 24), during the DSS-65 support for Ahead, turbo decoder lock was lost intermittently beginning at 0920z through 1014z due to heavy rain. This anomaly resulted in the loss of 153 frames of SSR data. See DR #M107623 more information. * On day 357 (Dec 23), during the DSS-55 support for Behind, turbo decoder lock was lost briefly at 1200z. This anomaly resulted in the loss of five frames of SSR data. * On day 360 (Dec 26), during the DSS-45 support for Behind, turbo decoder lock was lost briefly at 0713z due to bad weather. This anomaly resulted in the loss of 132 frames of SSR data. See DR #C109709 more information. * On day 362 (Dec 28), during the DSS-65 support for Behind, turbo decoder lock was lost intermittently beginning at 1425z through 1612z. This anomaly resulted in the loss of 1151 frames of SSR data. See DR #M107626 more information. * On day 360 (Dec 26), the 27th SECCHI stepped calibration on Behind was executed at 1310z for the aphelion in the orbit. * The average daily SSR playback volume during the week was 3.0 gigabits for Ahead, and 3.5 gigabits for Behind. Week 01 (Dec 30-Jan 5) * On day 364 (Dec 30), during the DSS-65 support for Ahead, turbo decoder lock was lost intermittently beginning at 0805z through 0815z. This anomaly resulted in the loss of nine frames of SSR data. * On day 004 (Jan 4), during the DSS-55 support for Ahead, turbo decoder lock was lost intermittently beginning at 1035z through 1308z. This anomaly resulted in the loss of 1118 frames of SSR data. See DR #N109322 more information. * On day 003 (Jan 3), the MOPS team detected that the assessment data processing for STEREO Ahead had stopped working since Wednesday, January 1st, 2014 due to a disk problem on the archive server vernon. The disk permissions issue was corrected at 003-1700z and the assessment data for days 001003 were reprocessed on Sunday. * Overall coverage for Ahead was 18.4 hours short during the week. This led to the following data gaps: * On day 364 (Dec 30), the SSR science partitions on Ahead filled as follows: SWAVES (Part 13) reached 100% full at 2317z for 0.7 hours. PLASTIC (Part 17) reached 95% full at 2247z for 1.2 hours. The primary cause was the accumulated shortage of track time throughout the week. * On day 365 (Dec 31), the SSR science partitions on Ahead filled as follows: SWAVES (Part 13) remained 100% full at 0000z for 8.7 hours. PLASTIC (Part 17) remained 95% full at 0000z for 8.7 hours. The primary cause was the accumulated shortage of track time throughout the week. * On day 001 (Jan 1), the SSR science partitions on Ahead filled as follows: SWAVES (Part 13) reached 100% full at 1004z for 2.3 hours. SWAVES (Part 13) reached 100% full at 1902z for 5.0 hours. PLASTIC (Part 17) reached 95% full at 2300z for 1.0 hours. The primary cause was the accumulated shortage of track time throughout the week. * On day 002 (Jan 2), the SSR science partitions on Ahead filled as follows: SWAVES (Part 13) remained 100% full at 0000z for 9.2 hours. SWAVES (Part 13) reached 100% full at 2029z for 3.5 hours. IMPACT (Part 15) reached 95% full at 0814z for 1.6 hours. IMPACT (Part 15) reached 95% full at 2209z for 1.9 hours. PLASTIC(Part 17) remained 95% full at 0000z for 9.3 hours. PLASTIC(Part 17) reached 95% full at 2125z for 3.6 hours. The primary cause was the accumulated shortage of track time throughout the week. * On day 003 (Jan 3), the SSR science partitions on Ahead filled as follows: SWAVES (Part 13) remained 100% full at 0000z for 9.1 hours. IMPACT (Part 15) remained 95% full at 0000z for 9.1 hours. PLASTIC(Part 17) remained 95% full at 0000z for 9.1 hours. The primary cause was the accumulated shortage of track time throughout the week. * On day 004 (Jan 4), the SSR science partitions on Ahead filled as follows: SWAVES (Part 13) reached 100% full at 0512z for 5.8 hours. The primary cause was the accumulated shortage of track time throughout the week. * On day 005 (Jan 5), the SSR science partitions on Ahead filled as follows: SWAVES (Part 13) reached 100% full at 0931z for 10.0 hours. PLASTIC (Part 17) reached 95% full at 1323z for 6.3 hours. The primary cause was the accumulated shortage of track time throughout the week. * On day 004 (Jan 4), during the DSS-63 support for Behind, turbo decoder lock was lost intermittently beginning at 1244z through 1354z. This anomaly resulted in the loss of 1650 frames of SSR data. See DR #N109323 more information. * On day 364 (Dec 30), PLASTIC conducted real-time commanding on Behind at 2215z to reduce the telemetry schedule. * Overall coverage for Behind was 16.4 hours short during the week. This led to the following data gaps: * On day 001 (Jan 1), the SSR science partitions on Behind filled as follows: SWAVES (Part 13) reached 100% full at 1841z for 1.5 hours. The primary cause was the accumulated shortage of track time throughout the week. * On day 002 (Jan 2), the SSR science partitions on Behind filled as follows: SWAVES (Part 13) reached 100% full at 0631z for 8.5 hours. SWAVES (Part 13) reached 100% full at 2027z for 3.5 hours. PLASTIC (Part 17) reached 95% full at 1421z for 0.9 hours. PLASTIC (Part 17) reached 95% full at 2054z for 3.1 hours. The primary cause was the accumulated shortage of track time throughout the week. * On day 003 (Jan 3), the SSR science partitions on Behind filled as follows: SWAVES (Part 13) remained 100% full at 0000z for 11.5 hours. IMPACT (Part 15) reached 95% full at 0415z for 7.6 hours. PLASTIC(Part 17) remained 95% full at 0000z for 11.7 hours. The primary cause was the accumulated shortage of track time throughout the week. * On day 004 (Jan 4), the SSR science partitions on Behind filled as follows: SWAVES (Part 13) reached 100% full at 0605z for 6.4 hours. IMPACT (Part 15) reached 95% full at 1041z for 1.8 hours. PLASTIC (Part 17) reached 95% full at 0747z for 3.1 hours. The primary cause was the accumulated shortage of track time throughout the week. * On day 005 (Jan 5), the STEREO BEHIND observatory was demoted into Standby Mode via Autonomy rule #124 at 0946z due to an unhealthy IMU-B (Gyro). During Sunday afternoon's DSS-25 track, additional diagnostic data was downlinked and analyzed by the engineering team. Initial indications are that the X-axis path length controller has failed on IMU-B. The BEHIND observatory remained in standby mode, coarse pointing, with all instruments continuing to collect science data except SECCHI which will be reconfigured by the SECCHI team on Monday. During Sunday evening's DSS-45 track, IMU-A, which was switched off in October of 2012 to preserve lifetime, was powered on and after its performance was verified, it was switched into service at 006-0457z. * On day 006 (Jan 6), during Monday afternoon's DSS-26 track, with IMU-A in use, the SECCHI guide telescope was enabled for use, fine pointing was re-established, and the BEHIND observatory was promoted back to Operational Mode at 2118z. Also, the failed IMU-B was powered off 2118z. The SECCHI team sent real-time commands to re-open the COR2 telescope cover at 22:33, and the COR1 telescope cover at 00:14 on Jan 7. All the SECCHI telescopes continued to take data during throughout the period, even with the COR1 and COR2 doors closed. * The average daily SSR playback volume during the week was 2.0 gigabits for Ahead, and 2.7 gigabits for Behind. * Since IMU-A on STEREO Behind is close to the end of its operational lifetime, and there is a desire to go to reduced gyro operations as quickly as possible, the MOC has come up with an interim reduced gyro mode of operation until the complete set of autonomy rules for reduced gyros is ready. There will be a Go/Nogo meeting today, and this is expected to be implemented later today. * The IMU failure on Behind is very similar to the failure on Ahead early in the mission. However, pathlength corrections were seen on Ahead in the period leading up to the failure, but not on Behind. The IMU on Ahead lasted 6 months before failing, while IMU-B lasted 14 months. * SECCHI asked about the imminent thruster warnings that were sent to the instrument during recovery operations. There were two thruster warnings within minutes of each other. There were no actual thruster firings. SECCHI is concerned about this because successive commands to close the COR2-B door can cause excessive preload on the door. Week 02 (Jan 6-12) * The 19th high-gain antenna calibration will be performed on Ahead at 19:00 UT on Tuesday, Jan 7. The HGA calibration on Behind has been cancelled due to the recent IMU failure. * Ahead has 8 passes during the week. Overall coverage is short 13.6 hours, mainly between Sunday, Jan 5 (of Week 1) and Wednesday, Jan 8. 70 meter passes are scheduled for Thursday, Jan 9 (D43), Friday, Jan 10 (D63), and Saturday, Jan 10 (D63). There will be one pass at 160 kbps: Wednesday, Jan 8 (D34). * Behind has 11 passes during the week, and overall coverage is nominal. There are two 70 meter passes, scheduled for Tuesday, Jan 7 (D14), and Saturday, Jan 11 (D63). Two passes will be carried out at 160 kbps, both on Monday, Jan 6 (D45 and D26). Week 03 (Jan 13-19) * The 64th momentum dump on Ahead is scheduled for Thursday, Jan 16 with ignition at 13:30 UT * Ahead has 7 passes during the week. Overall coverage is short 12.2 hours, mainly Monday-Thursday, Jan 13-16. There are two 70 meter supports scheduled, on Friday, Jan 17 (D43), and Saturday, Jan 18 (D63). * Behind has 10 passes during the week. Overall coverage is short 15.2 hours, with the shortfalls occurring Monday-Friday. No 70 meter supports are scheduled. The following passes will be carried out at 160 kbps: Monday, Jan 13 (D26), Tuesday, Jan 14 (D25), and Wednesday, Jan 15 (D55). Week 4 (Jan 20-26) * The 59th momentum dump on Behind is scheduled for Monday, Jan 20, with ignition at 23:00 UT. * Ahead has 9 passes during the week. Overall coverage is short 16.4 hours, spread throughout the week except Saturday. 30-40% data loss is expected most days. No 70 meter supports are scheduled. Two passes will be carried out at 160 kbps, both on Saturday, Jan 25 (D16 and D45). * Behind has 10 passes during the week. Overall coverage is short 10.5 hours, with the shortfall Wednesday-Friday. No 70 meter passes are scheduled. The following passes will be carried out at 160 kbps: Thursday, Jan 23 (D26), Friday, Jan 24 (D26), Saturday, Jan 25 (D55), and Sunday, Jan 26 (D26). Week 5 (Jan 27-Feb 2) * Ahead has 8 passes during the week, and overall coverage is nominal. 70 meter passes are scheduled for Monday, Jan 27, Wednesday, Jan 29, Friday, Jan 31, and Saturday, Feb 1, all using station 63. * Behind has 9 passes during the week, and overall coverage is nominal. 70 meter passes are scheduled for Tuesday, Jan 28, and Wednesday, Jan 29, both using station 63. The following passes will be carried out at 160 kbsp, both using station 26: Thursday, Jan 30, and Saturday, Feb 1. Week 6 (Feb 3-9) * Ahead has 8 passes during the week, and overall coverage is nominal. 70 meter passes are scheduled for Wednesday, Feb 5 (D43), Friday, Feb 7 (D63), and Sunday, Feb 9 (D63). The following passes will be carried out at 160 kbps: Monday, Feb 3 (D34), and Tuesday, Feb 4 (D26). * Behind has 10 passes during the week, and overall coverage is short 11.2 hours, mainly between Monday-Thursday. 70 meter passes are scheduled for Wednesday, Feb 5, Thursday, Feb 6, and Saturday, Feb 8. The station 26 pass on Friday, Feb 7, will be carried out at 160 kbps. Other * The link margin for the Behind spacecraft with the 70 meter stations at 480 kbps is predicted to dip just below 2dB for a couple of months starting in week 5. The MOC is looking into whether these stations will have to drop to 360 kbps during this period, or whether we can just ride it out. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 02: M Jan 06 (006) Behind: Recovered to operational mode on IMU-A at 21:18 UT. T Jan 07 (007) Ahead: HGA calibration, 19:00 UT W Jan 08 (008) T Jan 09 (009) F Jan 10 (010) S Jan 11 (011) S Jan 12 (012) Notes: * Significant telemetry shortages are expected for the Ahead spacecraft during the week. ------------------------------------------------------------------------------- Scheduled activities for Week 03: M Jan 13 (013) T Jan 14 (014) W Jan 15 (015) T Jan 16 (016) Ahead: Momentum dump, 13:30 UT F Jan 17 (017) S Jan 18 (018) S Jan 19 (019) Notes: * Significant telemetry shortages are expected for both spacecraft during the week. ------------------------------------------------------------------------------- Scheduled activities for Week 04: M Jan 20 (020) Behind: Momentum dump, 23:00 UT T Jan 21 (021) W Jan 22 (022) T Jan 23 (023) F Jan 24 (024) S Jan 25 (025) S Jan 26 (026) Notes: * Significant telemetry shortages are expected for both spacecraft during the week. ------------------------------------------------------------------------------- Scheduled activities for Week 05: M Jan 27 (027) T Jan 28 (028) W Jan 29 (029) T Jan 30 (030) F Jan 31 (031) S Feb 01 (032) S Feb 02 (033) ------------------------------------------------------------------------------- Scheduled activities for Week 06: M Feb 03 (034) T Feb 04 (035) W Feb 05 (036) T Feb 06 (037) F Feb 07 (038) S Feb 08 (039) S Feb 09 (040) Notes: * Significant telemetry shortages for the Behind spacecraft are expected during the week. ------------------------------------------------------------------------------- Upcoming events: 2014: * Jan 20 Behind: End use of 480 kbps on 70 m DSN subnet (TBC) * Apr 21 Behind: Resume use of 480 kbps on 70 m DSN subnet * Apr 29 Behind: Mercury transit * Sep 07-Nov 15 Behind: Passage of Comet Siding Spring through HI2-B * Oct 15 Behind: End use of 480 kbps on 70 m DSN subnet * Oct 17 Behind: Comet Siding Spring encounter with Mars 2015: * Jan 20 - Mar 28 (TBC) Behind: Spacecraft behind Sun * Mar DAWN - Ceres arrival * 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