STEREO Weekly Meeting Minutes for 2015-10-06 (Week 41) 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 40 (Sep 28-Oct 4) * On day 271 (Sep 28), during the Ahead support with DSS-26, the 80 kW transmitter tripped off-line at 1955z due to a coolant flow issue. The coolant flow issue was corrected and the transmitter was placed on-line at 2045z. The 80 kW transmitter provided approximately 6 dB increase in received power than a nominal 20 kW uplink from a 34m station. Plans are to use the more powerful 80 kW transmitter to help with Behind recovery. The coolant flow anomaly resulted in the loss of 50 minutes of commanding and 8 frames of real-time data during the transition from one-way to two-way. See DR# G116606 for more information. * 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 111 degrees C and decreasing with the HGA angle at 8.3 degrees and increasing, with respect to the spacecraft-Sun line. * On day 272 (Sep 29), during the DSS-43 support for Ahead, the segmented frequency acquisition sequence, which will be used to restore communications on the Behind observatory, was tested on Ahead. All 18 one kHz frequency steps were tested twice. While stepping down through the 1 kHz segments, on segment #9 going down in frequency, the transponder locked to the BLF and accepted 9 no-op commands as expected. An interesting finding, but not unexpected, was that the transponder continued to follow the moving carrier and accept all commands sent for the remaining 27 segments. * On day 273 (Sep 30), the 80th momentum dump on Ahead was executed successfully at 2230z, which imparted a delta V of 0.102 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. * This week, data for the following days was played back from the C&DH routine SSR partition playback: 2015-270-11:58:42z through 2015-276-16:43:17z 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 80 Mbits during this 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%. Two ESA passes are scheduled during the week. * 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. The IMU will be on during this momentum dump. * Ahead has 8 passes during the week. 70 meter coverage is short 2 hours during the week, on Tuesday and Wednesday. 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. Week 46 (Nov 9-15) * Ahead starts the week still on the first side lobe, with IMPACT being prime. * Ahead has 9 passes during the week, with one pass at 10 kbps, seven passes at 360 kbps, and one pass at 633 bps. * Temporary macros will be loaded to RAM on Monday, Nov 9, to allow higher real-time rates for the instruments during the week. * At the end of the last pass on Monday, Nov 9, the HGA will be switched to the main lobe, with a 1 degree offset. Immediately following this pass ending at 21:55 UT the NOAA antenna partners should be able to lock onto the space weather beacon telemetry. At this point the nominal telemetry rate will be 240 kbps on 70 meter stations, or 30 kbps on 34 meter stations. However, if a 70 meter pass is at high elevation throughout the pass, the telemetry rate can be increased to 360 kbps, which will be the case for all the passes Tuesday through Sunday. * In spite of the increase in the telemetry rate, the instruments will remain at their first-side-lobe rates throughout the week, until the SSR partitions are reconfigured on Monday, Nov 16. * On Tuesday, Nov 10, the SSR pointers will be moved to start reading out the SSR. The SSR partitions will be read out at least twice between Tuesday and Sunday. * On Sunday, Nov 15, the original macros will be reloaded into RAM to prepare for switching back to nominal operations mode. SECCHI will also perform some real-time commanding. The spacecraft will not switch to space weather mode at the end of the pass to give the buffers a chance to empty out. Week 47 (Nov 16-22) * Ahead has 8 passes during the week, with five passes at 360 kbps, and three passes at 240 kbps. Overall coverage is short 4.6 hours between Tuesday-Friday. * On Monday, Nov 16, during the station 63 pass for Ahead starting at 10:45 UT, the SSR will be emptied and repartitioned. Updated data handling and MOPS macros will be loaded into RAM. * Normal science operations will resume on Tuesday, Nov 17, starting with the station 63 pass for Ahead. The IMPACT SWEA and STE instruments will be powered on, and the SECCHI and SWAVES instruments will be allowed to upload schedules. * An uplink array test using stations 25 and 26 will be carried out with Ahead on Thursday, Nov 19. The station 26 transmitter will be operating at 80 kW. * A return-to-service engineering demo with station 55 will be carried out on Saturday, Nov 21. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- 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. ------------------------------------------------------------------------------- Scheduled activities for Week 46: M Nov 09 (313) T Nov 10 (314) 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 W Nov 11 (315) T Nov 12 (316) F Nov 13 (317) S Nov 14 (318) S Nov 15 (319) Notes: * Ahead starts the week on the first side lobe, in IMPACT-prime mode. The instruments will continue to produce telemetry at the first-side-lobe rates through the week, until the SSR partitions are reconfigured on Monday, Nov 16. * No tracks for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Scheduled activities for Week 47: M Nov 16 (320) Ahead: SSR playback and reconfiguration Ahead: No SECCHI telemetry 10:00-10:20 UT Ahead: Resume prime science real-time telemetry rates Ahead: End S/C telemetry in space weather broadcast T Nov 17 (321) Ahead: Instrument recommissioning, IMPACT SWEA/STE on W Nov 18 (322) T Nov 19 (323) Ahead: HGA on main lobe, riding soft stop, 360 kbps Ahead: Uplink array test (DSS-25 & 26) F Nov 20 (324) S Nov 21 (325) Ahead: Return-to-service engineering demo with station 55 S Nov 22 (326) Notes: * After Friday, Nov 20, the Behind spacecraft will be able to operate on the first side lobe after it is recovered. ------------------------------------------------------------------------------- Upcoming events: Behind events are contingent on recovering the spacecraft. 2015: * 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