STEREO Weekly Meeting Minutes for 2016-07-26 (Week 30) ANNOUNCEMENTS ------------- * The SSC reports that the Korean Space Weather Center has started tracking space weather beacon data from the STEREO Ahead spacecraft, using their 13 meter parabolic dish antenna on the island of Jeju, South Korea. The addition of this station is important because the only other beacon tracking station at a similar longitude is the one in Koganei, Japan. Having more than one station in this part of the world is critical for getting maximum space weather coverage from STEREO Ahead. 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 29 (Jul 18-24) * On day 200 (Jul 18), during the DSS-26 support for Ahead, telemetry lock was lost at 1929z due to the station losing electrical power. Telemetry lock was restored at 2001z and command capability at 2046z. SSR pointers were repositioned and all SSR data were recovered. See DR# G117324 for more information. * On day 202 (Jul 20), during the DSS-54 support for Ahead, turbo decoder lock was lost briefly at 1234z. This anomaly resulted in the loss of 5 frames of SSR data. * On day 202 (Jul 20), a project interface test using Ahead was successfully conducted with the new 34m BWG station at the Canberra complex, DSS-36. Telemetry and ranging locks were received as planned and 4 no-op commands were successfully received by the observatory. Station performance was nominal for STEREO Ahead. Real-time telemetry data were successfully ingested and processed by the MOC. * On day 203 (Jul 21), during the DSS-43 support for Ahead, turbo decoder lock was intermittent for four minutes beginning at 2323z due to a high system noise temperature. This anomaly resulted in loss of 2558 frames of real-time and SSR playback telemetry. See DR# N110332 for more information. * On day 204 (Jul 22), during the DSS-65 support for Ahead, turbo decoder lock was lost intermittently beginning at 0721z through 0756z. This anomaly resulted in loss of 167 frames of real-time and SSR playback telemetry. See DR# N110333 for more information. * On day 206 (Jul 24), the DSS-54 support for Ahead was declared red at BOT due to an antenna azimuth control anomaly. SSR pointers were repositioned at the start of the next track to minimize data loss. This anomaly resulted in the loss of 5 hours of command, tracking, and real-time telemetry. See DR# M109492 for more information. * On day 206 (Jul 24), during the DSS-25 support for Ahead, turbo decoder lock was lost intermittently beginning at 1645z through 1953z. This anomaly resulted in loss of 3 frames of real-time and SSR playback telemetry. * The Ahead observatory operated nominally during this week. * On day 200 (Jul 18), the 35th SECCHI stepped calibration was executed at 1300z for aphelion in the Ahead orbit. This was the 4th SECCHI stepped calibration roll to be conducted without gyro use. The SECCHI/COR1 team reported that the roll data were usable, but showed more jitter than other recent calibration rolls. One polarizer sequence out of a total of nine was rejected to improve the results. * The average daily science data return for Ahead was 6.0 Gbits during this week. * There were no tracks for Behind during the week. Week 30 (Jul 25-31) * The station 35 subreflector was red during the pass for Ahead last night (Jul 25). To compensate, the telemetry rate during the pass was reduced to 120 kbps, and the same will be done during the station 35 pass tonight (Jul 26). A station 26 pass at 360 kbps was added to the schedule on Wednesday, Jul 27, to compensate for the loss of telemetry coverage. 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. 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. 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. This is a backup test, and may be cancelled if the previous test with station 34 is successful. * 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. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- 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) ------------------------------------------------------------------------------- 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) ------------------------------------------------------------------------------- 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