STEREO Weekly Meeting Minutes for 2011-12-20 (Week 51) ANNOUNCEMENTS ------------- * The SECCHI telescopes observed the perihelion passage of Comet Lovejoy Dec 15-16. This represents only the second time that a comet has been observed at EUV wavelengths, and the first time that a sungrazing comet has survived perihelion since the launch of SOHO. See below for details. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * All subsystems on both spacecraft are nominal. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 50 (Dec 12-18) * On day 351 (Dec 17), during the DSS-63 support for Ahead, turbo decoder lock was lost briefly at 0900z. This anomaly resulted in the loss of two frames of SSR data. A DR has been requested. * On day 346 (Dec 12), during the DSS-63 support for Behind, turbo decoder lock was lost briefly at 1338z. This anomaly resulted in the loss of two frames of SSR data. See DR# N107815 for more information. * On day 348 (Dec 14), during the DSS-15 support for Behind, real-time telemetry awas lost at 2258z due to the telemetry servers being switched for upgrading at the DSN. Real-time telemetry was restored at 2302z after the MOC rebound to the on-line telemetry server. This anomaly resulted in the loss of four minutes of real-time telemetry. All SSR data was received. See DR# N107817 for more information. * On day 350 (Dec 16), the MOC was notified that the DSS 43 antenna was red and that the scheduled support for Behind at 2320z was deleted due to corrective maintenance for the x-band transmitter. A 480 kbps support with DSS-63 to start at 351-1225z with a duration of 5.4 hours was added to prevent science data loss. The blind acquisition contingency procedure was executed and telemetry was received at 351-1301z. SSR pointers were repositioned and all SSR data were received. See DR# C108378 for more information. * On day 351 (Dec 17), during the DSS-25 support for Behind, telemetry lock was lost at 2238z as the antenna stopped tracking. The antenna was reset, the uplink was re-swept, and telemetry lock was re-established at 2310z. SSR pointers were repositioned and all SSR data were received. See DR# G112189 for more information. * The average daily SSR playback volume was 5.1 gigabits for Ahead, and 5.1 gigabits for Behind. Week 51 (Dec 19-25) * Momentum dumps are scheduled during the week. These are a bit early, but have been moved forward because of the subsequent holidays. * The 37th momentum dump on Behind occurred successfully yesterday (Dec 19), with ignition at 16:00 UT. * The 43rd momentum dump on Ahead was just successfully completed at the time of the telecon (Dec 20), with ignition at 17:00 UT. * Four ESA test tracks are scheduled during the week, with the following schedule: Dec 20, 00:45 UT, Ahead, New Norcia, 2 hours Dec 20, 19:10 UT, Behind, Cebreros, 35 minutes (shadow track) Dec 21, 03:30 UT, Behind, New Norcia, 2 hours Dec 21, 05:35 UT, Ahead, Cebreros, 35 minutes The Cebreros track on Dec 20 is a shadow track overlapping the station 15 track. The other tracks are all followed by 70 meter tracks, and the pointers will be moved back at the end of these test tracks. * The New Norcia test track with Ahead went well last night (Dec 20, UTC). Telemetry was 33 minutes late because of a problem with the authentication password. Signal level was good, comparable to the DSN stations. The ranging tuning is still being adjusted, so the ranging data are not considered valid, but were transmitted for practice. Since almost all the tracks are through the DSN, tracking data still meets requirements. The telemetry was played in realtime through JPL. This worked well. The pointers were reset to bring the data back down through a DSN station. The missing 35 minutes of data could be recovered from the station, if necessary. * December 25 is Christmas day. Monday, Dec 26, is a holiday at APL. * Ahead has 70 meter passes every day during the week. The station 14 pass on Wednesday, Dec 21 will be carried out at 720 kbps. There are 9 passes during the week, and overall coverage is nominal. * Behind has 70 meter passes on Monday, Dec 19 (D63), Tuesday, Dec 20 (D63), Wednesday, Dec 21 (D63), Friday, Dec 23 (D43 at 720 kbps), Saturday, Dec 24 (D14 at 720 kbps), and Sunday, Dec 25 (D63). There are 11 passes during the week, and overall coverage is nominal. The station 15 pass on Dec 21 will be carried out at 240 kbps. Week 52 (Dec 26 - Jan 1) * Ahead has 70 meter passes on Thursday, Dec 29, and Sunday, Jan 1, both using station 14. There are 15 passes during the week, and overall coverage is nominal. The station 34 pass on Saturday, and the station 54 pass on Sunday, will be carried out at 240 kbps. * Behind has a 70 meter pass on Tuesday, Dec 27, at 720 kbps using station 63. There are 11 passes during the week, and overall coverage is nominal. The station 34 pass early on Sunday, Jan 1, will be carried out at 240 kbps. Week 1 (Jan 2-8) * Monday, Jan 2, is a holiday at APL. * Tracks using the ESA New Norcia station are scheduled for Jan 5 on Ahead, and Jan 8 on Behind. These will appear on the schedule as station 32. No tracks have yet been scheduled on the Cebreros station 62 due to conflicts. * Ahead has 70 meter passes on Monday, Jan 2, and Saturday, Jan 7, both using station 14. There are 14 passes during the week, and overall coverage is nominal. The station 26 pass on Thursday, Jan 5, and the station 45 pass on Sunday, Jan 8, will be carried out at 240 kbps. * Behind has a 70 meter pass on Saturday, Jan 7, using station 43 at 720 kbps. There are 12 passes during the week, and overall coverage is nominal. The station 15 pass on Wednesday will be carried out at 240 kbps. Week 2 (Jan 9-15) * HGA calibration rolls are scheduled on Behind on Tuesday, Jan 10, starting at 16:00 UT, and on Ahead on Thursday, Jan 12, starting at 19:00 UT. Each spacecraft will be rotated by +/- 1/2 degree, and the maneuver will last about one hour. * The 20th SECCHI stepped calibration roll for Ahead is scheduled for Tuesday, Jan 10, starting at 02:40 UT. This will be the midpoint roll. System momentum is expected to be around 1 N-m-s. * A 2 hour pass for Behind is scheduled on the ESA New Norcia D32 station on Saturday, Jan 14, starting at 03:20 UT. * Ahead has a 70 meter pass on Thursday, Jan 12, using station 43. There are 11 passes during the week, and overall coverage is nominal. The station 34 pass on Saturday, Jan 14, will be carried out at 240 kbps. * Behind has 13 passes during the week, and overall coverage is nominal. There are no 70 meter or high elevation passes during the week. Week 3 (Jan 16-22) * A 2.25 hour pass for Behind is scheduled on the ESA New Norcia D32 station on Thursday, Jan 19, starting at 06:30 UT. * Ahead has 70 meter passes on Monday, Jan 16 (D63), Tuesday, Jan 17 (D43), Thursday, Jan 19 (D14, D43 at 720 kbps), and Saturday, Jan 21 (D43 twice, first at 720 kbps). There are 10 passes during the week, and overall coverage is nominal. * Behind has 70 meter passes on Monday, Jan 16, Tuesday, Jan 17, Thursday, Jan 19, Saturday, Jan 21, and Sunday, Jan 22, all using station 63. There are 15 passes during the week, and overall coverage is nominal. The station 34 pass on Monday will be carried out at 240 kbps. Week 4 (Jan 23-29) * Ahead has 70 meter passes on Wednesday, Jan 25 (D43), Friday, Jan 27 (D14), Saturday, Jan 28 (D63), and Sunday, Jan 29 (D63). There are 13 passes during the week, and overall coverage is nominal. A 6.1 hour pass is scheduled using the ESA New Norcia station D32 late Monday. * Behind has 70 meter passes on Tuesday, Jan 24 (D63), Thursday, Jan 26 (D14 at 720 kbps), and Saturday, Jan 28 (D43 at 720 kbps, D63). There are 11 passes during the week, and overall coverage is nominal. The station 15 pass on Saturday, Jan 28, will be carried out at 240 kbps. A 4.75 hour pass is scheduled using the ESA New Norcia station D32 on Thursday. Other * Comet Lovejoy was successfully observed by the STEREO Ahead and Behind spacecraft Dec 15-16. SECCHI took special subfield images at high cadence to observe the comet at EUV wavelengths. This represents only the second time that a comet has been observed in the EUV. The observations taken by the SECCHI EUVI telescopes are quite spectacular, as are the coronagraph images from COR1, COR2, and HI1. The comet defied expectations by surviving perihelion passage, and at least one ground observer at southern latitudes has reported seeing the comet without a telescope just before sunrise. This comet was also observed by SDO/AIA, SOHO/LASCO and UVCS, Hinode/SOT, and PROBA2/SWAP. COORDINATED OBSERVATIONS ------------------------ ------------------------------------------------------------------------------- Scheduled activities for Week 51: M Dec 19 (353) Behind: Momentum dump, 16:00 UT Ahead: 70 meter downlink on station 63 Behind: 70 meter downlink on station 63 T Dec 20 (354) Ahead: Momentum dump, 17:00 UT Ahead: 70 meter downlink on station 14 Behind: 70 meter downlink on station 63 Ahead: Test track with New Norcia (D32) at 00:45 UT Behind: Test track with Cebreros (D62) at 19:10 UT W Dec 21 (355) Ahead: 70 meter downlink on station 14 Behind: 70 meter downlink on station 63 Ahead: Test track with Cebreros (D62) at 05:35 UT Behind: Test track with New Norcia (D32) at 03:30 UT T Dec 22 (356) Ahead: 70 meter downlink on station 14 F Dec 23 (357) Ahead: 70 meter downlink on station 63 Behind: 70 meter downlink on station 43 S Dec 24 (358) Ahead: 70 meter downlink on station 14 Behind: 70 meter downlink on station 14 S Dec 25 (359) Ahead: 70 meter downlink on station 14 Behind: 70 meter downlink on station 63 ------------------------------------------------------------------------------- Scheduled activities for Week 52: M Dec 26 (360) T Dec 27 (361) Behind: 70 meter downlink on station 63 W Dec 28 (362) T Dec 29 (363) Ahead: 70 meter downlink on station 14 F Dec 30 (364) S Dec 31 (365) S Jan 01 (001) Ahead: 70 meter downlink on station 14 ------------------------------------------------------------------------------- Scheduled activities for Week 01: M Jan 02 (002) Ahead: 70 meter downlink on station 14 T Jan 03 (003) W Jan 04 (004) T Jan 05 (005) F Jan 06 (006) S Jan 07 (007) Ahead: 70 meter downlink on station 14 Behind: 70 meter downlink on station 43 S Jan 08 (008) ------------------------------------------------------------------------------- Scheduled activities for Week 02: M Jan 09 (009) T Jan 10 (010) Ahead: SECCHI stepped calibration roll, 02:40 UT Behind: HGA calibration, 16:00 W Jan 11 (011) T Jan 12 (012) Ahead: HGA calibration, 19:00 Ahead: 70 meter downlink on station 43 F Jan 13 (013) S Jan 14 (014) S Jan 15 (015) ------------------------------------------------------------------------------- Scheduled activities for Week 03: M Jan 16 (016) Ahead: 70 meter downlink on station 63 Behind: 70 meter downlink on station 63 T Jan 17 (017) Ahead: 70 meter downlink on station 43 Behind: 70 meter downlink on station 63 W Jan 18 (018) T Jan 19 (019) Ahead: 70 meter downlink on stations 14 and 43 Behind: 70 meter downlink on station 63 F Jan 20 (020) S Jan 21 (021) Ahead: 70 meter downlink on station 43 (twice) Behind: 70 meter downlink on station 63 S Jan 22 (022) Behind: 70 meter downlink on station 63 ------------------------------------------------------------------------------- Scheduled activities for Week 04: M Jan 23 (023) T Jan 24 (024) Behind: 70 meter downlink on station 63 W Jan 25 (025) Ahead: 70 meter downlink on station 43 T Jan 26 (026) Behind: 70 meter downlink on station 14 F Jan 27 (027) Ahead: 70 meter downlink on station 14 S Jan 28 (028) Ahead: 70 meter downlink on station 63 Behind: 70 meter downlink on stations 43 and 63 S Jan 29 (029) Ahead: 70 meter downlink on station 63 ------------------------------------------------------------------------------- Upcoming events: 2012: * 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