STEREO Weekly Meeting Minutes for 2015-08-25 (Week 35) ANNOUNCEMENTS ------------- * None. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * Ahead is now operating on the first side lobe. * There are currently no communications with the Behind spacecraft. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 34 (Aug 17-23) * On day 231 (Aug 19), the 70 meter DSS-14 support for Ahead was declared red due to a failed sub-reflector. The support was moved to DSS-25, a 34 meter support. However, the observatory was configured for the higher 70 meter data rates, 10 kbps down and 500 bps up. Commands to stop the SSR playback and switch to 3 kbps down and 125 bps up were sent at 1525z. Initial acquisition of telemetry for the DSS-25 support occurred 43 minutes late at 1558z with ranging enabled. As the next scheduled support was with DSS-25, the support duration was extended to a total of 9.2 hours. With the greater than 20 degree elevation and maser receive use on DSS-25, the 3 kbps downlink was stable but with very little telemetry margin. No telemetry frames or commands were dropped. This anomaly resulted in the loss of 4.75 hours of higher rate real-time science data and spacecraft SSR playback data. See DR# G116526 for more information. * Since the DSS-25 pass was conducted under very favorable conditions, and there was still almost no margin on the pass, the MOC is not recommending using 3 kbps with the 34 meter stations at this point. * On day 235 (Aug 23), during the DSS-63 support for Ahead, turbo decoder lock was lost briefly at 1139z. This anomaly resulted in the loss of one frame 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 120 degrees C and decreasing with the HGA angle at 7.0 degrees and increasing, with respect to the spacecraft-Sun line. * On day 226 (Aug 24), G&C fine pointing loss began to occur intermittently. This coincides when two of the wheels reached the wheel speed dead zone for zero speed avoidance. * On day 234 (Aug 22) at 1305z, the wheel bad offset parameter on Ahead was decreased in G&C RAM to 23 rad/sec. It will take a full momentum cycle to assess the pointing performance of this change. The offset parameter had been previously increased for solar conjunction. * On day 231 (Aug 19), G&C parameters release 1.3.3 was loaded to G&C RAM on Ahead. This release increased the propulsion subsystem enable delay for G&C thruster use to 60 seconds in preparation for No Gyro Operations (NGO) to be deployed later this year. * On day 233 (Aug 21), during the DSS-63 support for Ahead, the SSR read pointer for the C&DH routine housekeeping telemetry partition was moved to day 232-0000z to resume playing back the most current data each day. This will be done to ensure attitude history data is available to the science teams, provide additional G&C data for investigating a fine pointing issue, and assess the current observatory performance. Since exiting solar conjunction, it has been playing back data from the SLVS anomalies that occurred during solar conjunction. * This week, data for the following days was played back from the C&DH routine SSR partition playback from solar conjunction: 2015-144-21:18:51z through 2015-146-07:05:44z 2015-147-08:41:18z through 2015-148-10:45:58z 2015-148-10:46:28z through 2015-149-12:29:41z 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. * 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. Their will be a presentation by the MOC in November on the plans for exiting from side-lobe operations. * The average daily science data return for Ahead, while operating on the 1st side lobe of the HGA, was 97 Mbits during this week. Week 35 (Aug 24-30) * Ahead starts the week at an SPE angle of 3.9 degrees, on the first side lobe, with SWAVES being prime. * The 79th momentum dump on Ahead was successfully carried out on Monday, Aug 24, with ignition at 18:00 UT. The momentum dump was performed with IMU-2 on. The MOC tightened up parameters for this maneuver, in preparation for moving to no gyro operations later in the year. * The IMPACT SIT calibration tables will be uploaded on Wednesday, Aug 26, during the station 14 support. This is about a four hour pass, with an increased uplink speed (compared to the second side lobe) of 500 bps. * PLASTIC is also uploading commands to address the current issues that were seen earlier this year. * Ahead has 19 passes during the week, with seven passes at 10 kbps, and twelve passes at 633 bps, with overall space weather coverage of 41%. * Behind starts the week at an SPE angle of 2.2 degrees. There will be no passes for Behind during the week. Week 36 (Aug 31-Sep 6) * Ahead starts the week at an SPE angle of 4.1 degrees, on the first side lobe, with IMPACT being prime. * G&C parameter set 1.3.3 will be written to EEPROM on Ahead on Monday, Aug 31. * The MOC will resume using ESA stations with Ahead, to increase the amount of space weather coverage. The first pass will be a 7 hour Cebreros support on Sep 1. A total of 100 hours of ESA support is allocated. * Ahead has 18 passes during the week, with eight passes at 10 kbps, and ten passes at 633 bps, with overall space weather coverage of 35%. * Behind starts the week at an SPE angle of 2.1 degrees. There will be no passes for Behind during the week. Week 37 (Sep 7-13) * APL will be closed on Monday, Sep 7, for the Labor Day holiday. * Ahead starts the week at an SPE angle of 4.3 degrees, on the first side lobe, with SWAVES being prime. * Ahead has 15 passes during the week, with seven passes at 10 kbps, and eight passes at 633 bps, with overall space weather coverage of 31%. An ESA pass is scheduled for Tuesday, Sep 8. * Behind starts the week at an SPE angle of 2.0 degrees. There will be no passes for Behind during the week. Week 38 (Sep 14-20) * Ahead starts the week at an SPE angle of 4.5 degrees, on the first side lobe, with IMPACT being prime. * Ahead has 16 passes during the week, with eight passes at 10 kbps, and eight passes at 633 bps, with overall space weather coverage of 31%. * Behind starts the week at an SPE angle of 1.9 degrees. There will be no passes for Behind during the week. 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 station 35 pass for Ahead on Tuesday, Sep 22, will be a project interface test of the new uplink software with ranging. Real-time telemetry will flow during this test, but there will be no instrument commanding. * 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 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. However, 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. * Oct 1 marks the beginning for STEREO of the third extended mission. * Ahead has 12 passes during the week, with seven passes at 10 kbps, and five passes at 633 bps, with overall space weather coverage of 31%. * 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. * 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 26%. * Behind starts the week at an SPE angle of 2.0 degrees. There will be no passes for Behind during the week. Other * The problem reported last week concerning ingesting SECCHI data from NRL to the SSC has now been resolved. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 35: M Aug 24 (236) Ahead: Momentum dump, 18:00 UT T Aug 25 (237) W Aug 26 (238) Ahead: IMPACT SIT calibration table upload T Aug 27 (239) F Aug 28 (240) S Aug 29 (241) S Aug 30 (242) 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 36: M Aug 31 (243) T Sep 01 (244) W Sep 02 (245) T Sep 03 (246) F Sep 04 (247) S Sep 05 (248) S Sep 06 (249) 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 37: M Sep 07 (250) Labor Day T Sep 08 (251) W Sep 09 (252) T Sep 10 (253) F Sep 11 (254) S Sep 12 (255) S Sep 13 (256) 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 38: M Sep 14 (257) T Sep 15 (258) W Sep 16 (259) T Sep 17 (260) F Sep 18 (261) S Sep 19 (262) S Sep 20 (263) 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 39: M Sep 21 (264) T Sep 22 (265) Ahead: Project interface test with station 35 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) T Sep 29 (272) Ahead: Test of frequence acquisition mode with station 43 W Sep 30 (273) T Oct 01 (274) Begining 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) 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. ------------------------------------------------------------------------------- Upcoming events: Behind events are contingent on recovering the spacecraft. 2015: * Nov 10 Ahead: HGA on main lobe, offpoint 1 degree, 240 kbps Ahead: SSR playback and reconfiguration, S/C checkout Ahead: Resume space weather broadcast to NOAA stations * Nov 12 Ahead: Instrument recommissioning * Nov 16 Ahead: HGA on main lobe, offpoint 1 degree, 360 kbps Behind: Resume Behind recovery efforts * Nov 20 Behind: HGA on 1st side lobe * Nov 30 Ahead: HGA on main lobe, offpoint 1 degree, 480 kbps * Dec 30 Ahead: HGA on main lobe 2016: * Jan 2 Behind: HGA on main lobe, offpoint 1 degree Behind: SSR playback and reconfiguration, S/C checkout * Jan 5 Behind: Instrument recommissioning * Jan 12 Behind: HGA on main lobe * Jan 27 Both: HGA calibration * Mar 16 Both: Post Solar Conjunction Assessment Review * Jul 5 Juno arrival at Jupiter 2017: * Jul 11 Ahead: Switch downlink rate to 160 kbps * Jul 22 Behind: Switch downlink rate to 160 kbps 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