STEREO Weekly Meeting Minutes for 2016-03-08 (Week 10) 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 09 (Feb 29-Mar 6) * On day 060 (Feb 29), during the DSS-45 support for Ahead, turbo decoder lock was lost intermittently beginning at 0756z through 0800z. This anomaly resulted in the loss of 85 frames of real-time and SSR playback data. * On day 060 (Feb 29), during the DSS-26 support for Ahead, the MOC lost command bind and spacecraft transponder lost command lock for 40 seconds due to the station transmitter modulation anomaly at 2329z. Command bind was re-established at 061-0031z. All commands and telemetry data were received. See DR# G116985 for more information. * On day 062 (Mar 2), during the DSS-65 support for Ahead, turbo decoder lock was lost intermittently beginning at 1118z through 1139z. This anomaly resulted in the loss of 4 frames of real-time and SSR playback data. * On day 063 (Mar 3), during the DSS-54 support for Ahead, turbo decoder lock was lost briefly at 1730z. This anomaly resulted in the loss of 6 frames of real-time and SSR playback data. * On day 064 (Mar 4), during the DSS-65 support for Ahead, turbo decoder lock was lost intermittently beginning at 1727z through 1737z. This anomaly resulted in the loss of 31 frames of real-time and SSR playback data. * On day 066 (Mar 6), during the DSS-55 support, turbo decoder lock was lost briefly at 1400z. This anomaly resulted in the loss of 3 frames of real-time and SSR playback data. * On day 066 (Mar 6), during the DSS-25 support for Ahead, turbo decoder lock was lost intermittently beginning at 2024z through 2335z. This anomaly resulted in the loss of 78 frames of real-time and SSR playback data. See DR# G116991 for more information. * The Ahead observatory operated nominally during this week on the center of the HGA main lobe. The HGA feed assembly was at 112 degrees C and decreasing with the HGA angle at 8.5 degrees and increasing, with respect to the spacecraft-Sun line. * The average daily science data return for Ahead was 5.4 Gbits during this week. * On day 063 (Mar 3), during the DSS-26 34m support for Behind, using the 80 kW transmitter to minimize 70m contentions, 324 commands were sent for battery state of charge recovery. * On day 064 (Mar 4), during the DSS-26 34m support for Behind, using the 80 kW transmitter to minimize 70m contentions, 279 commands were sent for battery state of charge recovery. * On day 066 (Mar 6), during the DSS-43 70m support for Behind, 380 commands were sent for transmitter carrier recovery. No downlink signal was detected by 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. * The MOC is currently preparing for the first uplink array pass for Behind on Mar 17. There will be a telecon on Thursday to discuss preparations. This first array pass will be for battery recovery. The plan is to have one set of uplink array passes per month, with each set consisting of one pass for battery conditioning, and another for carrier recovery. The Allen Telescope Array will be supporting many of these passes, as well as Green Bank when available. Behind will enter the Arecibo field-of-view in late April. * The uplink margin on the low gain antenna returned to the nominal 6 dB on Behind on Mar 3. The downlink margin doesn't return to the nominal 3 dB until December. Week 10 (Mar 7-13) * The station 43 track early Monday (Mar 7) was missed due to the receiver being red. There was not enough time to move pointers to compensate, so there will be an approximately 13 hour gap in the data, between 0 to 13 UT, for all instruments. The estimated return to service for station 43 is 0 UT on day 72 (Mar 12), which means that station 43 won't be available for the planned pass on day 70 (Mar 10). The MOC will look into getting time on the ESA stations to compensate. * Daylight Savings Time starts in the U.S. on Sunday, Mar 13. * Ahead has 13 passes during the week, and overall coverage is nominal. There are seven passes at 720 kbps, one at 360 kbps, two at 240 kbps, and three at 160 kbps. It is possible to go to 360 kbps with station 26 if the elevation is above 25 degrees for the entire pass. * Behind starts the week at an SPE angle of 10.9 degrees. Recovery efforts for Behind are on Friday, Saturday, and Sunday, Mar 11-13. The battery recovery tracks will be carried out with the 80 kW transmitter on station 26. The Allen Telescope Array will be listening during the Sunday effort. 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 2 hours, with the rest on 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. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 10: M Mar 07 (067) T Mar 08 (068) W Mar 09 (069) T Mar 10 (070) F Mar 11 (071) S Mar 12 (072) S Mar 13 (073) Daylight Savings Time starts in U.S. ------------------------------------------------------------------------------- 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) ------------------------------------------------------------------------------- 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