STEREO Weekly Meeting Minutes for 2016-03-16 (Week 11) ANNOUNCEMENTS ------------- * None INSTRUMENT and SPACECRAFT STATUS -------------------------------- * Ahead is operating nominally on the main lobe of the high gain antenna. * There are currently no communications with the Behind spacecraft. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 10 (Mar 7-13) * On day 067 (Mar 7), the DSS-43 support for Ahead was declared red at BOT due to a downlink receiver anomaly. This anomaly resulted in the loss of 2.2 hours of command, tracking, and real-time telemetry and approximately 8 hours of SSR playback data for each instrument from 067-0000z through 0800z. See DR# C111903 for more information. * On day 068 (Mar 8), as the ETRO for DSS-43 was 071-0113z, an ESA New Norcia, DSS-74, support for Ahead was added on day 070 to minimize data loss from the loss of the DSS-43 support on day 070. * On day 070 (Mar 10), at BOT for the ESA New Norcia DSS-74 support for Ahead, the station was declared red due to a mechanical issue. SSR pointers were repositioned for the next support. This anomaly resulted in the loss of 3.75 hours of command, tracking, and real-time telemetry. * On day 070 (Mar 10), the DSS-43 support for Ahead was declared red at BOT due to a downlink receiver anomaly. This anomaly resulted in the loss of 2.4 hours of command, tracking, and real-time telemetry and approximately 3.2 hours of SECCHI SSR playback data at 071-1355z. See DR# C111922 for more information. * On day 070 (Mar 10), during the DSS-65 support for Ahead, turbo decoder lock was lost intermittently beginning at 1007z through 1238z. This anomaly resulted in the loss of 6 frames of SSR playback data. * On day 071 (Mar 11), additional science data from the Ahead observatory from day 041-2200z through 042-0746z was ingested into the MOC archive and new versions of data products, including Level Zero files, were created. These new data were received from DSS-35 on time; however, the MOC archive server failed to ingest the SSR playback IDR files at the time as its configuration file did not include DSS-35. DSS-35 is a new station placed in service in October of 2014. Recall that Ahead was conducting side lobe operations and only using 70m stations for SSR playbacks from August 2014 through November 2015 and the communication anomaly was ongoing for Behind. Day 042 was the only use of DSS-35 on STEREO that contained SSR playback data. All real-time data from each use of DSS-35 was ingested into the archive satisfactory. The DSS-35 station ID has been added to the configuration file for both STEREO Ahead and Behind archive servers. * On day 072 (Mar 12), during the DSS-43 support for Ahead, turbo decoder lock was lost nearly continuously between 0456z and 0711z due to heavy rain and thunderstorms at the Canberra complex. This anomaly resulted in the loss of 2 to 18 hours of SSR data depending upon the instrument. See DR# C111933 for more information. * On day 073 (Mar 13), during the DSS-26 support for Ahead, turbo decoder lock was lost intermittently between 2221z and 2318z. This anomaly resulted in the loss of 197 frames of SSR data. * The Ahead observatory operated nominally during this week on the center of the HGA main lobe. The HGA feed assembly was at 111 degrees C and decreasing with the HGA angle at 8.7 degrees and increasing, with respect to the spacecraft-Sun line. * On day 071 (Mar 11), the SECCHI SSR science partition (#19) filled and blocked at 1355z for 3.2 hours. This was due to the loss of the DSS-43 support on the day before. * The average daily science data return for Ahead was 4.8 Gbits during this week. * On day 071 (Mar 11), during the DSS-26 34m support for Behind, using the 80 kW transmitter to minimize 70m contentions, 234 commands were sent for battery state of charge recovery. * On day 072 (Mar 12), during the DSS-26 34m support for Behind, using the 80 kW transmitter to minimize 70m contentions, 351 commands were sent for battery state of charge recovery. * On day 073 (Mar 13), during the DSS-63 70m support for Behind, 400 commands were sent for transmitter carrier recovery. The Allen Telescope Array observed concurrently, however, no downlink signal was detected by them or the DSN. Due to the duration of the support and the increased commands for each step, only 19 of the 36 frequency segments were commanded. Three commands must be received sequentially to power on the transmitter. Week 11 (Mar 14-20) * The first uplink array pass for Behind will be on Thursday, Mar 17. This will be a 4.75 hour battery recovery track using stations 24, 25, and 26. * A downlink source is needed to calibrate the stations for uplink array. Ahead will be used for this purpose just before the pass for Behind. To allow this to happen, Ahead will be commanded to the 160 kbps downlink rate at the end of the station 63 pass at 18:00 UT on Mar 17, instead of switching to the space weather beacon rate as usual. The switch to the beacon rate will be delayed until 22:25 UT. The 4.75 hour pass for Behind will be split between the calibration on Ahead for about 1.25 hours, and 2.7 hours for Behind. * Ahead has 11 passes during the week, and overall coverage is nominal. There are three passes at 720 kbps, two passes at 360 kbps, four passes at 240 kpbs, and two passes at 160 kbps. * Behind starts the week at an SPE angle of 11.4 degrees. Besides the phased array pass on Thursday, Mar 17, recovery efforts for Behind are on Friday, Saturday, and Sunday, Mar 18-20. The battery recovery tracks will be carried out with the 80 kW transmitter on station 26. All four passes are within 72 hours of each other. * After this week, recovery efforts for Behind will be reduced to every two weeks, with phased array attempts once per month. For the phased array attempts, there will be one track for battery recovery, and another for carrier acquisition. Week 12 (Mar 21-27) * A 2.75 hour DSN ranging test is scheduled for station 26 with Ahead on Mar 22. There will be no instrument commanding or SSR downlink during this pass. * The 86rd momentum dump for Ahead is scheduled for Wednesday, Mar 23, with ignition at 22:00 UT. This will be the 5th momentum dump without the gyros. * Ahead has 12 passes during the week, and overall coverage is nominal. There are four passes at 720 kbps, three passes at 360 kbps, three passes at 240 kbps, and two passes at 160 kbps. * Behind starts the week at an SPE angle of 11.9 degrees. There will be no passes for Behind. From this point on, attempts to contact Behind will occur only every other week, with phased uplink arrays used once per month. Week 13 (Mar 28-Apr 3) * A 2.6 hour DSN ranging test is scheduled for station 15 with Ahead on Monday, Mar 28. There will be no instrument commanding or SSR downlink during this pass. * Ahead has 9 passes during the week, and overall coverage is nominal. There are four passes at 720 kbps, four passes at 240 kbps, and one pass at 160 kbps. * Behind starts the week at an SPE angle of 12.3 degrees. Recovery efforts for Behind are on Friday, Saturday, and Sunday, Apr 1-3. The battery recovery tracks will be carried out with the 80 kW transmitter on station 26. The Allen Telescope Array will listen during the carrier recovery track. Week 14 (Apr 4-10) * The 33rd SECCHI stepped calibration roll is scheduled for Tuesday, Apr 5, starting at 10:45 UT. This will be the midpoint roll. System momentum is expected to be around 4 N-m-s. This will be the second stepped calibration roll without the gyros. * On Wednesday, Apr 6, the LGA uplink margin on Ahead with 70 m stations will return to the nominal 6 dB at 7.8 bps. * A 2.6 hour DSN ranging test is scheduled for Sunday, Apr 10, with station 55. There will be no instrument commanding or SSR playback during this test. * Ahead has 11 passes during the week, and overall coverage is nominal. There are two passes at 720 kbps, one at 360 kbps, five at 240 kbps, and three at 160 kbps. * Behind starts the week at an SPE angle of 12.8 degrees. There are no passes for Behind during the week. Week 15 (Apr 11-17) * Ahead has 11 passes during the week, and overall coverage is nominal. There is one pass at 720 kbps, four at 240 kbps, and six at 160 kbps. * A 5.5 hour phased uplink array pass using stations 24, 25, and 26 is scheduled for Behind battery recovery on Saturday, Apr 16, and another 7.1 hour phase uplink pass is scheduled for Sunday, Apr 17. The first approximately two hours of each pass is anticipated to be used for calibration with Ahead. Station 43 is also scheduled for three hours during the carrier recovery track on Apr 17 to listen for any signal from the Behind spacecraft. The Allen telescope array will also listen for a signal. It is not yet known whether Green Bank will be listening during the entire period. STEREO Behind will not yet be in the Arecibo field of view. * Allocations between Ahead and Behind will be made after experience with the track on Mar 17. The NOAA antenna partners need to know when Ahead will switch to space weather mode. Week 16 (Apr 18-24) * Ahead has 14 tracks during the week, and overall coverage is nominal. There are two tracks at 720 kbps, ten at 240 kbps, and two at 160 kbps. * Behind starts the week at an SPE angle of 13.5 degrees. There are no passes for Behind during the week. Week 17 (Apr 25-May 1) * The 87th momentum dump on Ahead is scheduled for Thursday, Apr 28, with ignition at 20:00 UT. This will be the 6th momentum dump without using the gyros. * Ahead has 12 tracks during the week, and overall coverage is nominal. There are 3 tracks at 720 kbps, one at 360 kbps, five at 240 kbps, and three at 160 kbps. * Behind starts the week at an SPE angle of 13.8 degrees. Recovery efforts for Behind are on Monday-Wednesday, Apr 25-27. The battery recovery tracks will be undertaken with the 80 kW transmitter on station 26. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 11: M Mar 14 (074) T Mar 15 (075) W Mar 16 (076) T Mar 17 (077) Ahead: Broadcasting at 160 kbps between 18:00-22:25 UT Behind: First recovery attempt using uplink phased array F Mar 18 (078) S Mar 19 (079) S Mar 20 (080) ------------------------------------------------------------------------------- Scheduled activities for Week 12: M Mar 21 (081) T Mar 22 (082) Ahead: Ranging test with station 26 W Mar 23 (083) Ahead: Momentum dump, 22:00 UT T Mar 24 (084) F Mar 25 (085) S Mar 26 (086) S Mar 27 (087) ------------------------------------------------------------------------------- Scheduled activities for Week 13: M Mar 28 (088) Ahead: Ranging test with station 15 T Mar 29 (089) W Mar 30 (090) T Mar 31 (091) F Apr 01 (092) S Apr 02 (093) S Apr 03 (094) ------------------------------------------------------------------------------- Scheduled activities for Week 14: M Apr 04 (095) T Apr 05 (096) Ahead: SECCHI stepped calibration roll, 10:45 UT W Apr 06 (097) Ahead: Resume LGA uplink capability on 70 m DSN T Apr 07 (098) F Apr 08 (099) S Apr 09 (100) S Apr 10 (101) Ahead: Ranging test with station 55 ------------------------------------------------------------------------------- Scheduled activities for Week 15: M Apr 11 (102) T Apr 12 (103) W Apr 13 (104) T Apr 14 (105) F Apr 15 (106) S Apr 16 (107) Behind: Phased uplink array battery recovery attempt S Apr 17 (108) Behind: Phased uplink array carrier recovery attempt ------------------------------------------------------------------------------- Scheduled activities for Week 16: M Apr 18 (109) T Apr 19 (110) W Apr 20 (111) T Apr 21 (112) F Apr 22 (113) S Apr 23 (114) S Apr 24 (115) ------------------------------------------------------------------------------- Scheduled activities for Week 17: M Apr 25 (116) T Apr 26 (117) W Apr 27 (118) T Apr 28 (119) Ahead: Momentum dump, 20:00 UT F Apr 29 (120) S Apr 30 (121) S May 01 (122) ------------------------------------------------------------------------------- Upcoming events: Behind events are contingent on recovering the spacecraft. 2016: * May 16 Both: Post Solar Conjunction Assessment Review * Jul 5 Juno arrival at Jupiter * Dec Behind: Resume LGA downlink capability on 70 m DSN 2017: 2018: * Mar 5 Ahead: Mercury transit 2019: * Mar Ahead: Switch downlink rate to 240 kbps for 34 meter * Apr Behind: Switch downlink rate to 240 kbps for 34 meter 2020: * May Behind: Switch downlink rate to 360 kbps for 34 meter * Jun Ahead: Switch downlink rate to 360 kbps for 34 meter * Jun Behind: Switch downlink rate to 480 kbps for 34 meter * Sep Ahead: Switch downlink rate to 480 kbps for 34 meter 2021: * Jul Behind: Switch downlink rate to 720 kbps for 34 meter * Aug Ahead: Switch downlink rate to 720 kbps for 34 meter