STEREO Weekly Meeting Minutes for 2015-09-22 (Week 39) ANNOUNCEMENTS ------------- * None. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * Ahead is operating nominally on the first side lobe. * There are currently no communications with the Behind spacecraft. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 38 (Sep 14-20) * On day 261 (Sep 18), during the support with DSS-14 for Ahead, the transmitter tripped off-line at 1628z due to an over current condition. This anomaly resulted in the loss of 15 frames of real-time data during the transition from two-way to one-way. While the transmitter became operational shortly after it tripped, to avoid further real-time data loss, MOps elected to remain one-way for the remainder of the track. See DR# G116597 for more information. * On day 262 (Sep 19), during the DSS-43 support for Ahead, turbo decoder lock was lost briefly at 2200z. This anomaly resulted in the loss of 13 frames of real-time data. * The Ahead observatory operated nominally during this week on the 1st side lobe of the HGA to prevent overheating of the HGA feed assembly which was at 113 degrees C and decreasing with the HGA angle at 7.9 degrees and increasing, with respect to the spacecraft-Sun line. * This week, data for the following days was played back from the C&DH routine SSR partition playback: 2015-256-00:23:21z through 2015-263-22:38:20z Specifically, this partition contains spacecraft bus data for science analysis and instrument status, i.e., attitude history, instrument thermal interface temperatures, heater performance, etc., which are used to create the attitude history and converted spacecraft housekeeping data products. * The following days have not played back yet: 071 through 133 = 63 days (inclusive) 146 through 231 = 86 days (inclusive) Total = 149 days This partition’s write pointer is being monitored to ensure that these days are not overwritten, which is currently predicted to do so after returning to the HGA main lobe on or about Nov 13th. At some point before then, the pointers will be moved to prevent overwriting data. * Once on the HGA main lobe, the in-situ instrument space weather science SSR data along with the spacecraft housekeeping data will be downlinked twice and verified before the SSR is reconfigured to resume nominal daily science operations. * The average daily science data return for Ahead, while operating on the 1st side lobe of the HGA, was 85 Mbits during this week. * There are currently no operations for Behind due to a small separation angle with the Sun. Attempts to recover the spacecraft will resume Nov 30. A test of the frequency acquisition mode for recovering Behind will be tested on Ahead on Sep 29. On Oct 8 there will be an uplink array test with Ahead using stations 24 & 25, and there will be additional uplink array tests at the rate of about one test per month. Once the uplink array capability is operational, it will be used on Behind, possibly starting sometime in early 2016. The uplink margin on Behind with the LGA will return to 6 dB in March 2016, and the downlink margin will return to 3 dB in December 2016. Week 39 (Sep 21-27) * Ahead starts the week at an SPE angle of 4.8 degrees, on the first side lobe, with SWAVES being prime. * The PIT test originally scheduled for the station 35 pass for Ahead on Tuesday, Sep 22, was cancelled and converted back to a normal pass. * Ahead has 13 passes during the week, with eight passes at 10 kbps, and five passes at 633 bps, with overall space weather coverage of 23%. * Behind starts the week at an SPE angle of 1.9 degrees. There will be no passes for Behind during the week. Week 40 (Sep 28-Oct 4) * Ahead starts the week at an SPE angle of 5.0 degrees, on the first side lobe, with IMPACT being prime. * The station 26 pass late on Monday, Sep 26, will be conducted with 80 kW on the transmitter. The normal uplink power is 20 kW during side lobe operations, and goes back down to 10 kW on the main lobe to save transmitter lifetime. A larger 80 kW transmitter is being installed at each DSN location in preparation for replacing the 70 meter stations with four 34 meter stations phased together for downlink, and using one station with increased power for uplink. * The station 43 pass for Ahead on Tuesday, Sep 29, will be used to test the frequency acquisition mode developed for recovering the Behind spacecraft. Two DSN receivers will be used during this pass, one in coherent mode and the other in non-coherent mode, so the science data should not be impacted. The uplink frequency will be sweeped many times during this test, so operating one receiver in non-coherent mode will preserve the data. There will be no instrument commanding during this pass. The spacecraft will stay on the HGA, so the downlink rate will remain at 10 kbps, but the uplink rate will be changed to 7.8 bps. * The 80th momentum dump on Ahead will be performed on Wednesday, Sep 30, with ignition at 22:30 UT. IMU-2 will be turned on during the momentum dump. * Oct 1 marks the beginning for STEREO of the third extended mission. * Ahead has 13 passes during the week, with eight passes at 10 kbps, and five passes at 633 bps, with overall space weather coverage of 32%. * Behind starts the week at an SPE angle of 1.9 degrees. There will be no passes for Behind during the week. Week 41 (Oct 5-11) * Ahead starts the week at an SPE angle of 5.2 degrees, on the first side lobe, with SWAVES being prime. * Uplink array testing will resume on Thursday, Oct 8, with stations 24 & 25. This is the third uplink array test, and the second on Ahead. This test will include commanding. The uplink rate will be 7.8 bps. The rate of certain HK APIDs will be increased to return more transponder data. The test duration is 5.9 hours. Tests will continue at about once per month, using different configurations. The MOC will be examining the telemetry in realtime, sending no-op commands. There will be no instrument commanding during the pass. * Ahead has 10 passes during the week, with seven passes at 10 kbps, and three passes at 633 bps, with overall space weather coverage of 26%. * Behind starts the week at an SPE angle of 2.0 degrees. There will be no passes for Behind during the week. Week 42 (Oct 12-18) * Ahead starts the week at an SPE angle of 5.4 degrees, on the first side lobe, with IMPACT begin prime. * Ahead has 15 passes during the week, with seven passes at 10 kpbs, and eight passes at 633 bps, with overall space weather coverage of 34%. * Behind starts the week at an SPE angle of 2.1 degrees. There will be no passes for Behind during the week. Week 43 (Oct 19-25) * Ahead starts the week at an SPE angle of 5.6 degrees, on the first side lobe, with SWAVES being prime. * Five ESA tracks are scheduled during the week. * Sun, Oct 25, will mark the 9th anniversary of STEREO's launch. * Ahead has 18 passes during the week, with seven passes at 10 kbps, and eleven passes at 633 bps, with overall space weather coverage of 44%. * Behind starts the week at an SPE angle of 2.2 degrees. There will be no passes for Behind during the week. Week 44 (Oct 26-Nov 1) * Ahead starts the week at an SPE angle of 5.7 degrees, on the first side lobe, with IMPACT being prime. * Daylight savings time ends in the U.S. on Sunday, Nov 1. * The commands for the momentum dump on Monday, Nov 2, will be loaded on Friday, Oct 30. * Ahead has 11 passes during the week, with seven passes at 10 kbps, and four passes at 633 bps, with overall space weather coverage of 22%. * Behind starts the week at an SPE angle of 2.4 degrees. There will be no passes for Behind during the week. Week 45 (Nov 2-8) * Ahead starts the week at an SPE angle of 5.9 degrees, on the first side lobe, with SWAVES being prime. * The 81st momentum dump on Ahead will be carried out on Monday, Nov 2, with ignition at 17:30 UT. * Ahead has 8 passes during the week. 70 meter coverage is short 2 hours during the week, on Tuesday, Wednesday, and Saturday. There are seven passes at 10 kbps, and one pass at 633 bps, with overall space weather coverage of 13%. * Behind starts the week at an SPE angle of 2.6 degrees. There will be no passes for Behind during the week. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 39: M Sep 21 (264) T Sep 22 (265) W Sep 23 (266) T Sep 24 (267) F Sep 25 (268) S Sep 26 (269) S Sep 27 (270) Notes: * Ahead operating on the first side lobe, in SWAVES-prime mode. * No tracks for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Scheduled activities for Week 40: M Sep 28 (271) Ahead: Test with 80 kW transmitter on station 26 T Sep 29 (272) Ahead: Test of frequence acquisition mode with station 43 W Sep 30 (273) Ahead: Momentum dump, 22:30 UT T Oct 01 (274) Beginning of 3rd extended STEREO mission. F Oct 02 (275) S Oct 03 (276) S Oct 04 (277) Notes: * Ahead operating on the first side lobe, in IMPACT-prime mode. * No tracks for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Scheduled activities for Week 41: M Oct 05 (278) T Oct 06 (279) W Oct 07 (280) T Oct 08 (281) Ahead: Uplink array test with stations 24 & 25. F Oct 09 (282) S Oct 10 (283) S Oct 11 (284) Notes: * Ahead operating on the first side lobe, in SWAVES-prime mode. * No tracks for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Scheduled activities for Week 42: M Oct 12 (285) T Oct 13 (286) W Oct 14 (287) T Oct 15 (288) F Oct 16 (289) S Oct 17 (290) S Oct 18 (291) Notes: * Ahead operating on the first side lobe, in IMPACT-prime mode. * No tracks for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Scheduled activities for Week 43: M Oct 19 (292) T Oct 20 (293) W Oct 21 (294) T Oct 22 (295) F Oct 23 (296) S Oct 24 (297) S Oct 25 (298) 9th STEREO launch anniversary Notes: * Ahead operating on the first side lobe, in SWAVES-prime mode. * No tracks for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Scheduled activities for Week 44: M Oct 26 (299) T Oct 27 (300) W Oct 28 (301) T Oct 29 (302) F Oct 30 (303) S Oct 31 (304) S Nov 01 (305) Daylight savings time ends in U.S. Notes: * Ahead operating on the first side lobe, in IMPACT-prime mode. * No tracks for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Scheduled activities for Week 45: M Nov 02 (306) Ahead: Momentum dump, 17:30 UT T Nov 03 (307) W Nov 04 (308) T Nov 05 (309) F Nov 06 (310) S Nov 07 (311) S Nov 08 (312) Notes: * Ahead operating on the first side lobe, in SWAVES-prime mode. * No tracks for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Upcoming events: Behind events are contingent on recovering the spacecraft. 2015: * Nov 10 Ahead: HGA on main lobe, offpoint 1 degree, 240 kbps Ahead: 30 kbps on 34 meter stations Ahead: Resume space weather broadcast to NOAA stations * Nov 15 Ahead: Resume prime science real-time telemetry rates * Nov 16 Ahead: SSR playback and reconfiguration Ahead: No SECCHI telemetry 10:00-10:20 UT Ahead: End S/C telemetry in space weather broadcast * Nov 17 Ahead: Instrument recommissioning, IMPACT SWEA/STE on * Nov 19 Ahead: HGA on main lobe, riding soft stop, 360 kbps Ahead: Uplink array test (DSS-25 & 26) * Nov 20 Behind: HGA on 1st side lobe * Nov 23 Ahead: 96 kbps on 34 meter stations * Nov 30 Ahead: HGA on main lobe, riding soft stop, 480 kbps Ahead: 120 kbps on 34 meter stations Behind: Resume Behind recovery efforts * Dec 2 Ahead: Begin No Gyro Operations (NGO) Ahead: First NGO momentum dump * Dec 14 Ahead: 160 kbps on 34 meter stations * Dec 28 Ahead: HGA on main lobe, riding soft stop, 720 kbps * Dec 30 Ahead: HGA on main lobe 2016: * Jan 2 Behind: HGA on main lobe, offpoint 1 degree, 240 kbps Behind: Resume space weather broadcast to NOAA stations Behind: SSR playback and reconfiguration, S/C checkout * Jan 5 Behind: HGA on main lobe, riding soft stop, 360 kbps Behind: SSR playback and reconfiguration * Jan 6 Behind: Instrument recommissioning, IMPACT SWEA/STE on * Jan 9 Behind: HGA on main lobe, riding soft stop, 480 kbps * Jan 11 Behind: HGA on main lobe, riding soft stop, 720 kbps * Jan 12 Ahead: First NGO SECCHI stepped calib. roll (date TBC) Behind: HGA on main lobe * Jan 27 Both: HGA calibration (NGO) * Mar 3 Behind: Resume LGA uplink capability on 70 m DSN * Apr 6 Ahead: Resume LGA uplink capability on 70 m DSN * 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 * Apr Behind: Switch downlink rate to 240 kbps 2020: * May Behind: Switch downlink rate to 360 kbps * Jun Ahead: Switch downlink rate to 360 kbps * Jun Behind: Switch downlink rate to 480 kbps * Sep Ahead: Switch downlink rate to 480 kbps 2021: * Jul Behind: Switch downlink rate to 720 kbps * Aug Ahead: Switch downlink rate to 720 kbps