STEREO Weekly Meeting Minutes for 2015-09-01 (Week 36) 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 35 (Aug 24-30) * On day 240 (Aug 28), before the beginning of the DSS-34 support for Ahead, the transmitter was declared red and the support remained downlink only for the duration. This anomaly resulted in the loss of 2.9 hours of commanding and two-way Doppler support. See DR# C111343 for more information. * On day 241 (Aug 29), before the beginning of the DSS-34 support for Ahead, the transmitter was declared red and the support remained downlink only for the duration. The DSN reported that the transmitter will be red through day 245-2300z (Sep 2). This anomaly resulted in the loss of 3.1 hours of commanding and two-way Doppler support. Therefore, on day 244 (Sep 1) the two supports with DSS-34 will be downlink only. See DR# C111349 for more information. * On day 241 (Aug 29), during the DSS-14 support for Ahead, three no-op commands were not received during the command link validation. Commanding has been pretty consistent for the last couple of week except for this event. The pass began at low elevation--the MOC does not know about the weather conditions. * 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 118 degrees C and decreasing with the HGA angle at 7.3 degrees and increasing, with respect to the spacecraft-Sun line. * On day 236 (Aug 24), the 79th momentum dump on Ahead was executed successfully at 1800z, which imparted a delta V of 0.091 m/sec. IMU2 was used for 1.1 hours and the momentum target was set to the nominal 15 Nms. In preparation of No Gyro Operations, tighter momentum dump command arguments and a 60 second propulsion subsystem delay were used. * On day 238 (Aug 26), IMPACT SIT successfully loaded to Ahead calibration tables for the on board matrix rates. Post solar conjunction, these tables could not be loaded due to their large size and the effects of solar scintillation on the low uplink rates. * On day 238 (Aug 26), PLASTIC updated the deflection table to maintain the power supply current that has been slowly increasing since the beginning of the year. The current is not actually increasing at the moment, but the voltage setting is still quite a bit lower than before solar conjunction. * On day 240, PLASTIC sent real-time commands to adjust the setting for switching from the main channel to the small channel. This is part of recommissioning the hardware settings after solar conjunction. * This week, data for the following days was played back from the C&DH routine SSR partition playback: 2015-236-00:00:00z through 2015-240-11:47:24z 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. * The average daily science data return for Ahead, while operating on the 1st side lobe of the HGA, was 90 Mbits during this week. * Planning for Behind recovery continues to move along. There will be test of the frequency mode acquisition strategy with Ahead on Sep 29. Planning has also resumed for arrayed uplink; there will be a telecon next week with the DSN. * A question was raised whether the Ahead spacecraft is now out of the scintillation zone, and the MOC affirmed that it was. 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 was 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. * The 80th momentum dump on Ahead will be performed on Wednesday, Sep 30, with ignition at 22:30 UT. * 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. 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. Other * A question was raised about whether the attitude control requirements would be changed for no gyro operations. The MOC does not anticipate any requirements changes, and points out that for the last approximately two years the spacecraft has had the gyros turned off for normal operations, and only turns them on during special maneuvers. The main effect that no gyro operations will have for the SECCHI instrument will be during calibration rolls. The MOC has not yet studied this, but anticipates that a longer settling time will be needed. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- 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) Ahead: Momentum dump, 22:30 UT 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. ------------------------------------------------------------------------------- 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. ------------------------------------------------------------------------------- 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