STEREO Weekly Meeting Minutes for 2016-06-21 (Week 25) 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 24 (Jun 13-19) * On day 166 (Jun 14), during the DSS-54 support for Ahead, turbo decoder lock was lost briefly at 1649z. This anomaly resulted in the loss of 33 frames of SSR data. * On day 167 (Jun 15), during the DSS-26 support for Ahead, turbo decoder lock was lost intermittently beginning at 1549z through 168-0010z due to increasing winds. This anomaly resulted in the loss of 252 frames of real-time and SSR data. See DR #G117254 for more information. * On day 168 (Jun 16), during the DSS-65 support for Ahead, turbo decoder lock was lost intermittently throughout the track due rain and switching to the lower performing XHEMT receiver as the maser was unavailable. SSR pointers were repositioned and all data was recovered on the subsequent support. See DR #M109422 for more information. * On day 168 (Jun 16), during the DSS-26 support for Ahead, turbo decoder lock was lost briefly at 1725z. This anomaly resulted in the loss of 1 frame of SSR data. * On day 168 (Jun 16), the STEREO AHEAD MOC and the DSN successfully tested binding to all three ESA stations, DSS-74, 83, and 84, to verify connectivity from ESOC firewall upgrades. * On day 169 (Jun 17), during the DSS-55 support for Ahead, turbo decoder lock was lost briefly at 1632z. This anomaly resulted in the loss of 1 frame of SSR data. * On day 170 (Jun 18), during the DSS-25 support for Ahead, turbo decoder lock was lost briefly at 1747z and again at 2044z. This anomaly resulted in the loss of 2 frames of SSR data. * On day 171 (Jun 19), during the DSS-55 support for Ahead, turbo decoder lock was lost briefly at 0817z. This anomaly resulted in the loss of 2 frames of SSR data. * On day 171, during the DSS-26 support for Ahead, the transmitter tripped off-line at 1833z due to a coolant flow alarm. The alarm was cleared and the support remained downlink only for the last 5.7 hours to prevent additional SSR data loss. This anomaly resulted in the loss of 174 frames of SSR and 5.7 hours of commanding and two-way tracking data. See DR# G117266 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 88 degrees C and decreasing with the HGA angle at 12.2 degrees and increasing, with respect to the spacecraft-Sun line. * On day 168 (Jun 16), PLASTIC adjusted the accumulation times of heavy ion data products. Also, the s-channel switch was adjusted when transitioning from the main channel to the small channel to improve science data return. * The average daily science data return for Ahead was 6.9 Gbits during this week. * Starting in July, attempts to contact Behind will be reduced to once monthly, alternating months between phased uplink array passes, and single-dish passes which have a wider beam. This will continue through June 2017, after which recovery attempts will be suspended until January 2020, when the nominal uplink rate returns to 125 bps. The next uplink array attempt will be Jul 16-17. * A question was raised about whether the high temperatures currently being experienced in California is affecting Goldstone operations. The DSN has been experiencing some problems with the coolant flows for the transmitters because of the heat. Week 25 (Jun 20-26) * Turbo decoder lock was lost briefly at 08:46 UT during the station 63 pass for Ahead yesterday (Jun 20), resulting in the loss of 19 telemetry frames. * The 80 kW transmitter on station 26 tripped offline yesterday (Jun 20) during the Behind battery recovery track due to a coolant issue. This resulted in the loss of 1 hour of transmit time. * Station 55 was declared red yesterday, and the MOC arranged for time on the ESA Malargue station as a substitute for today's pass. However, station 55 came back online today just 35 minutes late for the originally scheduled pass, and the remainder of the pass was carried out, so the Malargue pass was cancelled. SSR pointers were repositioned to avoid data loss. * The STEREO Subsystem Assessment Review is scheduled for 9-11:30 AM EDT on Friday, Jun 24. Team members can call into the review using the same telephone number as that used for the weekly telecons. The MOC is also setting up a Webex connection. A package for the review has been sent out, and is also available on the STEREO Data System. This review will cover the period between post solar conjunction and the end of April. If planning to attend at APL, please let the MOC know so that they can arrange it with visitor control. * Ahead has 10 passes during the week, and overall coverage is nominal. There are two passes at 720 kbps, two at 360 kbps, four at 240 kbps, and two at 160 kbps. * Behind starts the week at an SPE angle of 15.2 degrees. Recovery efforts for Behind are Monday-Wednesday, Jun 20-22. The battery recovery tracks will be undertaken with the 80 kW transmitter on station 26. The Allen Telescope Array will listen for a signal Behind spacecraft, along with Arecibo for 1.3 hours. Also, the radio science receiver will be used with station 14. Week 26 (Jun 27-Jul 3) * The 5th battery discharge operation on Ahead is scheduled for Monday, Jun 27, for about 2 hours starting at 17:00. This will be performed during the support, and should not interfere with normal operations. The battery state of charge will be reduced to about 80-85% and assessed, and then reset back to full charge. * An uplink frequency ramping test will be carried out between ESA/ESOC and STEREO Ahead between 1:00-3:30 UT on Tuesday, Jan 28. This test is in support of the Cassini mission. Science data collection will be unaffected, but 2-3 minute gaps in the space weather data are expected. * Ahead has 12 passes during the week, and overall coverage is nominal. There are three passes at 720 kbps, two at 360 kbps, four at 240 kbps, and three at 160 kbps. * Behind starts the week at an SPE angle of 15.2 degrees. There are no tracks for Behind. Week 27 (Jul 4-10) * Monday, July 4 is a holiday for APL. * Monday, July 4 is aphelion for Ahead. * The Juno mission will arrive at Jupiter late on July 4 (UT: early July 5), which is resulting in a tight DSN schedule. * The 89th momentum dump on Ahead is on Wednesday, Jul 6, at 16:00 UT. This will be the eighth momentum dump without using the gyros. * Ahead has 15 passes during the week, and overall coverage is nominal. There are four passes at 720 kbps, two at 360 kbps, five at 240 kbps, and four at 160 kbps. * Behind starts the week at an SPE angle of 15.1 degrees. There are no tracks for Behind during the week, since recovery attempts are now only once a month. Week 28 (Jul 11-17) * A MOC interface test with the new station 36 at Canberra is scheduled for Wednesday, Jul 13, for 1 hour starting at 14:00 UT. This will not involve the spacecraft. * Ahead has 10 passes during the week, and overall coverage is nominal. There are three passes at 720 kbps, one at 360 kbps, four at 240 kbps, and two at 160 kbps. * Behind starts the week at an SPE angle of 15.1 degrees. * Uplink array attempts for Behind are scheduled for July 16, 17. The first 1.9 hours each day will use the Ahead spacecraft to calibrate the phasing between the stations. There will be no SSR playback or instrument commanding during these passes. Following the calibration, there will be a 3.3 hour pass for Behind on Jul 16 for battery recovery, and a 5.3 hour pass on Jul 17 for carrier recovery. The elevation will drop below 27.5 degrees for the last 48 minutes, so a waiver has been requested; otherwise, the station 26 power would need to be reduced from 80 to 60 kW. Station 14 will listen for the Behind carrier, along with the Allen Telescope Array. Week 29 (Jul 18-24) * The 35th SECCHI stepped calibration roll for Ahead is scheduled for Monday, Jul 18, starting at 13:00 UT. System momentum will be about 6 N-m-s. This is the aphelion roll, and the fourth without using the gyros. * A 3 hour project interface test with the new station 36 at Canberra is scheduled for Wednesday, Jul 20. The new station is expected to be operational sometime later this year. The downlink rate will be 160 kbps, and there will be no SSR playback or instrument commanding during the pass. * Ahead has 12 passes during the week, and overall coverage is nominal. There are three passes at 720 kbps, three at 360 kbps, five at 240 kbps, and one at 160 kbps. * Behind starts the week at an SPE angle of 15.0 degrees. There are no tracks for Behind during the week. Week 30 (Jul 25-31) * Ahead has 11 passes during the week, and overall coverage is nominal. There are two passes at 720 kbps, two at 360 kbps, and seven at 240 kbps. One of the 70 meter passes was converted to a 34 meter pass to help out the Rosetta mission, which is nearing the end of their mission. * Behind starts the week at an SPE angle of 14.9 degrees. There are no tracks for Behind during the week. Week 31 (Aug 1-7) * Ahead has 12 passes during the week, and overall coverage is nominal. There are two passes at 720 kbps, two at 360 kbps, seven at 240 kbps, and one at 160 kbps. * Behind starts the week at an SPE angle of 14.7 degrees. There are no tracks for Behind during the week. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 25: M Jun 20 (172) T Jun 21 (173) W Jun 22 (174) T Jun 23 (175) F Jun 24 (176) Ahead: STEREO Subsystem Assessment Review S Jun 25 (177) S Jun 26 (178) ------------------------------------------------------------------------------- Scheduled activities for Week 26: M Jun 27 (179) Ahead: Battery maintenance, 17:00 UT T Jun 28 (180) Ahead: Uplink frequency ramping test with ESA/ESOC W Jun 29 (181) T Jun 30 (182) F Jul 01 (183) S Jul 02 (184) S Jul 03 (185) ------------------------------------------------------------------------------- Scheduled activities for Week 27: M Jul 04 (186) Independence Day Ahead: Aphelion T Jul 05 (187) Juno arrival at Jupiter W Jul 06 (188) Ahead: Momentum dump, 16:00 UT T Jul 07 (189) F Jul 08 (190) S Jul 09 (191) S Jul 10 (192) ------------------------------------------------------------------------------- Scheduled activities for Week 28: M Jul 11 (193) T Jul 12 (194) W Jul 13 (195) MOC interface test with station 36, 14:00 UT T Jul 14 (196) F Jul 15 (197) S Jul 16 (198) Behind: Phased array recovery attempt S Jul 17 (199) Behind: Phased array recovery attempt ------------------------------------------------------------------------------- Scheduled activities for Week 29: M Jul 18 (200) Ahead: SECCHI stepped calibration roll, 13:00 UT T Jul 19 (201) W Jul 20 (202) Ahead: Project interface test with station 36 T Jul 21 (203) F Jul 22 (204) S Jul 23 (205) S Jul 24 (206) ------------------------------------------------------------------------------- Scheduled activities for Week 30: M Jul 25 (207) T Jul 26 (208) W Jul 27 (209) T Jul 28 (210) F Jul 29 (211) S Jul 30 (212) S Jul 31 (213) ------------------------------------------------------------------------------- Scheduled activities for Week 31: M Aug 01 (214) T Aug 02 (215) W Aug 03 (216) T Aug 04 (217) F Aug 05 (218) S Aug 06 (219) S Aug 07 (220) ------------------------------------------------------------------------------- Upcoming events: Behind events are contingent on recovering the spacecraft. 2016: * 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