STEREO Weekly Meeting Minutes for 2016-08-02 (Week 31) 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 30 (Jul 25-31) * On day 207 (Jul 25), during the DSS-25 support for Ahead, turbo decoder lock was lost briefly at 1714z and again at 1929z. This anomaly resulted in the loss of two frames of SSR data. * On day 207 (Jul 25), during the DSS-35 support for Ahead, due to a failed Y-axis and the sub-reflector being fixed at 45 degrees, Mops reduced the downlink rate to 120 Kbps to add telemetry RF margin. The support was successful at the lower rate. See DR #C112231 for more information. * On day 208 (Jul 26), during the DSS-26 support for Ahead, turbo decoder lock was lost briefly at 1851z. This anomaly resulted in the loss of one frame of SSR data. * On day 208 (Jul 26), during the DSS-35 support for Ahead, due to a failed Y-axis and the sub-reflector being fixed at 45 degrees, Mops reduced the downlink rate to 120 Kbps to add telemetry RF margin. The support was successful at the lower rate. See DR #C112231 for more information. * On day 209 (Jul 27), during the DSS-55 support for Ahead, turbo decoder lock was lost briefly at 1050z and again at 1204z. This anomaly resulted in the loss of 28 frames of real-time and SSR playback telemetry. * On day 209 (Jul 27), during the DSS-26 support for Ahead, turbo decoder lock was lost briefly at 2014z. This anomaly resulted in the loss of one frame of SSR data. * On day 212 (Jul 30), during the DSS-55 support for Ahead, turbo decoder lock was lost briefly at 0939z, 1005z and again at 1034z. This anomaly resulted in loss of 221 frames of real-time and SSR playback telemetry. See DR #N110349 for more information. * On day 212 (Jul 30), during the DSS-25 support for Ahead, turbo decoder lock was lost briefly at 1835z. This anomaly resulted in the loss of one frame of SSR data. * The average daily science data return for Ahead was 5.9 Gbits during this week. * There were no tracks for Behind during the week. Week 31 (Aug 1-7) * The station 43 pass for last night (Aug 1) was deleted to assist with a pulsar emissions study. This pass wasn't needed for data recovery. * 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. Week 32 (Aug 8-14) * The 90th momentum dump on Ahead is scheduled for 19:30 UT on Tuesday, Aug 9. This will be the ninth momentum dump without using the gyros. * Station 34 will conduct the third engineering test of pointing to the Ahead spacecraft on Saturday, Aug 13, in support of the upcoming OSIRIS-REx mission. This is the first test with station 34. There will be no effect on operations. The spacecraft will remain in spaceweather mode. * Ahead has 13 passes during the week, and overall coverage is nominal. There are two passes at 720 kbps, four at 360 kpbs, six at 240 kbps, and one at 160 kbps. * Behind starts the week at an SPE angle of 14.6 degrees. There are no tracks for Behind during the week. Week 33 (Aug 15-21) * There will be an IONET router switch on Wednesday, Aug 17, between 14:15-15:00 UT, which is in between tracks. If the switch is unsuccessful, then the network will be restored to its present configuration before the next track. * Ahead has 15 passes during the week, and overall coverage is nominal. There is one pass at 720 kbps, five at 360 kbps, seven at 240 kbps, and two at 160 kbps. * Behind starts the week at an SPE angle of 14.4 deg. * The single station recovery tracks for the monthly recovery operations for Behind will be Aug 19-21 (Friday-Sunday). The 80 kW Station 26 transmitter will be used for the two battery recovery tracks on Friday and Saturday, and Station 14 will be used for the carrier recovery on Sunday. Week 34 (Aug 22-28) * Station 34 will conduct the fourth engineering test of pointing to the Ahead spacecraft on Monday, Aug 22, in support of the upcoming OSIRIS-REx mission. There will be no effect on operations. The spacecraft will remain in spaceweather mode. If the previous test with station 34 is successful, then this test may be changed to an attenuator test. There was some discussion of whether or not the spaceweather data would be flowed to the SSC. * Behind will be at perihelion on Aug 25 * Ahead has 14 passes during the week, and overall coverage is nominal. There are two passes at 720 kbps, two at 360 kbps, and ten at 240 kbps. * Behind starts the week at an SPE angle of 14.3 degrees. There are no tracks for Behind during the week. Week 35 (Aug 29-Sep 4) * Ahead has 12 passes during the week, and overall coverage is nominal. There is one pass at 720 kbps, two at 360 kpbs, eight at 240 kbps, and one at 160 kbps. * Behind starts the week at an SPE angle of 14.1 degrees. There are no tracks for Behind during the week. Week 36 (Sep 5-11) * Monday, Sep 5, is Labor Day, which is a holiday at APL. * Ahead has 11 passes during the week, and overall coverage is nominal. There are three passes at 720 kbps, four at 360 kbps, three at 240 kbps, and one at 160 kbps. * There are no tracks for Behind during the week. Week 37 (Sep 12-18) * Ahead has 8 passes during the week, and overall coverage is nominal. There are four passes at 720 kbps, one at 360 kbps, and three at 240 kbps. * Uplink array attempts for Behind are scheduled for Sep 17, 18. Each attempt will begin with 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 pass for Behind on Sep 17 for battery recovery, and a pass on Sep 18 for carrier recovery. Station 14 will listen for the Behind carrier, using the Radio Science Receiver. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- 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) ------------------------------------------------------------------------------- Scheduled activities for Week 32: M Aug 08 (221) T Aug 09 (222) Ahead: Momentum dump, 19:30 UT W Aug 10 (223) T Aug 11 (224) F Aug 12 (225) S Aug 13 (226) Ahead: Station 34 pointing test for OSIRIS-REx S Aug 14 (227) ------------------------------------------------------------------------------- Scheduled activities for Week 33: M Aug 15 (228) T Aug 16 (229) W Aug 17 (230) T Aug 18 (231) F Aug 19 (232) S Aug 20 (233) S Aug 21 (234) Notes * Single station recovery attempts for Behind, Aug 19-21 ------------------------------------------------------------------------------- Scheduled activities for Week 34: M Aug 22 (235) Ahead: Station 34 pointing test for OSIRIS-REx T Aug 23 (236) W Aug 24 (237) T Aug 25 (238) Behind: Perihelion F Aug 26 (239) S Aug 27 (240) S Aug 28 (241) ------------------------------------------------------------------------------- Scheduled activities for Week 35: M Aug 29 (242) T Aug 30 (243) W Aug 31 (244) T Sep 01 (245) F Sep 02 (246) S Sep 03 (247) S Sep 04 (248) ------------------------------------------------------------------------------- Scheduled activities for Week 36: M Sep 05 (249) Labor Day T Sep 06 (250) W Sep 07 (251) T Sep 08 (252) F Sep 09 (253) S Sep 10 (254) S Sep 11 (255) ------------------------------------------------------------------------------- Scheduled activities for Week 37: M Sep 12 (256) T Sep 13 (257) W Sep 14 (258) T Sep 15 (259) F Sep 16 (260) S Sep 17 (261) Behind: Phased array recovery attempt S Sep 18 (262) Behind: Phased array recovery attempt ------------------------------------------------------------------------------- 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