STEREO Weekly Meeting Minutes for 2015-11-10 (Week 46) ANNOUNCEMENTS ------------- * The STEREO Ahead high gain antenna is back on the main lobe, with a one degree offset. See below for details. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * Ahead is operating nominally. The SSR is being read out during the week, and the instruments will return to normal operations next week. * There are currently no communications with the Behind spacecraft. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 45 (Nov 2-8) * On day 310 (Nov 6), during the DSS-63 support for Ahead, the transmitter was red for the entire support. Also, the receiver dropped telemetry lock beginning at 1022z through 1030z due to the Y-axis sub-reflector brakes being set. These anomalies resulted in the loss of 2.8 hours of commanding and two tracking data and 41 frames of real-time science data. See DRs #M109067 and #M107916 for more information. * On day 311 (Nov 7), as there was a possibility of the soft command loss timer expiring should the DSS-63 transmitter continue to be red, a two hour contingency support with ESA’s Malargüe station DSS-84 was added for 311-1800 through 2000z to ensure commands were received. This support was successful. The planned DSS-63 support on day 311 was also successful. * 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 108 degrees C and decreasing with the HGA angle at 9.2 degrees and increasing, with respect to the spacecraft-Sun line. The observatory will return to the HGA main lobe, riding along a one degree offset, on day 314, November 10th. The 15 months of in-situ instruments science data on the SSR will be played back twice and NOAA antenna partners can once again close the RF link on the space weather broadcast. On day 321, November 17th, instruments will begin reconfiguration for resuming nominal daily science data return. * On day 306 (Nov 2), the 81st momentum dump was executed successfully at 1730z, which imparted a delta V of 0.114 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 307, as C&DH routine SSR partition is predicted overwrite solar conjunction data, the read pointer was repositioned back to where the playback left off, DOY 071-0942z. This week, data for the following days were played back from the C&DH routine SSR partition playback: 2015-071-09:42:43z through 2015-076-02:17:14z 2015-304-09:58:10z through 2015-306-06:22:10z 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. On day 314, November 10th, these data along with the in-situ instruments space weather science SSR data will begin downlinked twice and verified before the SSR is reconfigured on day 320, November 16th in preparations for resuming nominal daily science operations. 076 through 133 = 58 days (inclusive) 146 through 231 = 86 days (inclusive) 306 through 316 = 11 days (inclusive) Total = 154 days * The average daily science data return for Ahead, while operating on the 1st side lobe of the HGA, was 61 Mbits during this week. Week 46 (Nov 9-15) * Yesterday, Nov 9, the high gain antenna on Ahead returned to the main lobe, with a 1 degree offset due to the soft stop. The antenna angle will gradually decrease as it follows the soft stop, returning to the center of the main lobe by the end of the year. The antenna temperature increased to 118-119 degrees C. Today, it has stabilized to 120 degrees C. * The MOC will now start playing back the data recorded on the SSR. These data will be played back at least twice. The SSR will be reconfigured on Monday next week, and the instruments will start to return to their normal operating mode on Tuesday. * A detailed schedule for the events during the week has been sent out, including command windows for the instruments. * Temporary macros were loaded to RAM on Monday, Nov 9, to allow higher real-time rates for the instruments during the week. * 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. * Now that the HGA is back on the main lobe, the NOAA antenna partners should be able to lock onto the space weather beacon telemetry again. The station in Bochum, Germany was able to lock onto the signal and bring down space weather data for processing in the SSC. There was also a short contact from the station at APL. The smaller antenna station in Kiel, Germany reports that they were able to see the carrier wave, but the signal strength was not quite strong enough to lock onto. They believe that they'll be able to lock on with an improvement of 1 dB or so, which should happen in the next week or two. * There were no SECCHI packets in the beacon telemetry stream. The reason is not known. However, SECCHI images were coming down without problem during the DSN pass today. * 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, Nov. 10 through Sunday, Nov. 15. * Starting today, Nov 10, the uplink rate will increase to 2000 bps for all stations. * A go/no-go review for No Gyro Operations will be carried out on Thursday, Nov 12. * 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 to reduce their telemetry rate. This will result in no images being taken from some time before 23:20 UT on Nov 15 until sometime on Nov 16 or 17. The spacecraft will not switch to space weather mode at the end of the pass to give the buffers a chance to empty out. * After some discussion, it was decided that SECCHI will not produce any image telemetry between 23:00 UT on Nov 15, and 0:50 UT on Nov 17. There will be no images on Nov 16. * Ahead has 9 passes during the week, with one pass at 10 kbps, seven passes at 360 kbps, and one pass at 633 bps (on Monday, Nov 9). Overall coverage is nominal. * Behind starts the week at an SPE angle of 2.9 degrees. There will be no passes for Behind during the week. Week 47 (Nov 16-22) * Ahead starts the week at an SPE angle of 6.2 degrees. * Nominal DSN 70 meter track time coverage will be increased from 3 to 4 hours. * The MOC requested that the instrument teams, particularly SECCHI, hold off on reconfiguring back to normal science operations until Tuesday, Nov 17, to assist with the SSR reconfiguration. The first opportunity for commanding on Tuesday will be at 08:50 UT. * 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. The in situ data partitions will be slightly larger than they were before solar conjunction. * The last time that spacecraft housekeeping will be in the beacon channel will be Monday , Nov. 16th at the end of the Startion 63 support (13:45 UT). No more housekeeping in beacon after that. * Normal science operations will resume on Tuesday, Nov 17, starting with the station 63 pass for Ahead. Later on Tuesday is a ESA Malargüe track good for uploading. The IMPACT SWEA and STE instruments will be powered on, and the SECCHI and SWAVES instruments will be allowed to upload schedules. The SWEA high voltage can begin to be ramped up. * All passes during the week will be supported at the MOC. Since the uplink rate will be 2000 bps, all the instruments should be able to share the uplink. Using the voice loops for coordinating commanding is recommended. * The fourth uplink array test will be carried out on Thursday, Nov 19. This will involve arraying together two stations, one at 80 kW transmitter power, and the other at 20 kW. * On Thursday, Nov 19, the nominal telemetry rate on the 70 meter stations will be increased to 360 kbps. * A return-to-service track for station 55 is scheduled for Saturday, Nov 21. There will be no instrument commanding or SSR playback during this pass. * Ahead has 10 passes during the week, with six passes at 360 kbps, three passes at 240 kbps, and one pass at 30 kbps. Overall coverage is nominal. * Behind starts the week at an SPE angle of 3.2 degrees. There will be no passes for Behind during the week. Week 48 (Nov 23-29) * Ahead starts the week at an SPE angle of 6.4 degrees, with a nominal 70 meter telemetry rate of 360 kbps. * On Monday, Nov 23, G&C parameter set 1.3.4 will be written to EEPROM. * APL will be closed for the Thanksgiving holiday Thursday and Friday, Nov 26-27. * Ahead has 9 passes during the week, all at 360 kbps, and overall coverage is nominal. * Behind starts the week at an SPE angle of 3.5 degrees. There will be no passes for Behind during the week. Recovery operations resume the following week. Week 49 (Nov 30-Dec 6) * Ahead starts the week at an SPE angle of 6.5 degrees, riding the HGA soft stop. * The nominal rate on Ahead for 70 meter stations will increase to 480 kbps on Monday, Nov 30. * On Monday, Nov 30, updated fault protection rules will be written to RAM. * The 82nd momentum dump for Ahead is scheduled for Dec 2. Since this will be the first momentum dump under no-gyro operations, the dump will be shortened so that the target momentum is zero N-m-s, i.e. about half the normal dump. The telemetry rate will also be reduced to 96 kbps to maintain telemetry lock in case the pointing varies during the dump. * Ahead has 7 passes during the week, all at 480 kbps, and overall coverage is nominal. * Behind starts the week at an SPE angle of 3.9 degrees. * Behind recovery operations resume on Monday, Nov 30. There will be three passes over three days each week. The first two passes, both 4.5 hours, on Monday, Nov 30, and Tuesday, Dec 1, will attempt to power up the battery, and the third pass (4 hours), on Wednesday, Dec 2, will attempt to command on the transmitter. Time has been requested from the Arecibo and Green Bank observatories to listen during the Dec 2 pass. Week 50 (Dec 7-13) * Ahead starts the week at an SPE angle of 6.6 degrees, riding the HGA soft stop, with a nominal 70 meter telemetry rate of 480 kbps. * On Tuesday, Dec 8, C&DH release 1.1.11 and macro parameters 1.1.28 will be written to EEPROM. * A return-to-service track for station 34 is scheduled for Friday, Dec 11, with downlink at 120 kps. There will be no instrument commanding or SSR playback during the track. * Ahead has 10 tracks during the week, eight at 480 kbps, and two at 120 kbps, and overall coverage is short 2.9 hours between Friday to Sunday, Dec 11-13. * Behind starts the week at an SPE angle of 4.3 degrees. Recovery efforts for Behind are scheduled for Thursday-Saturday, Dec 10-12. Week 51 (Dec 14-20) * Ahead starts the week at an SPE angle of 6.8 degrees. * On Monday, Dec 14, the downlink rate for 34 m stations for Ahead will increase to 160 kbps. * Also on Monday, Dec 14, updated fault protection rules will be written to EEPROM. * Ahead has nine tracks during the week, with seven tracks at 480 kbps, one track at 240 kbps, and one track at 160 kbps. Overall coverage is short 7.9 hours between Monday and Saturday (DOY 348 to 353). No loss of data for the in-situ instruments is anticipated, but SECCHI should plan for the shortfall. * Behind starts week with SPE angle of 4.7 deg. Recovery efforts for Behind are scheduled with three tracks Monday-Thursday, Dec 14-17. Week 52 (Dec 21-27) * The 83rd momentum on Ahead is scheduled for Monday, Dec 21, with ignition at 15:30 UT. This dump is scheduled earlier than usual because the previous momentum dump was short. The telemetry rate will be switched to 96 kbps during the dump to maintain lock. * APL will be closed on Friday, Dec 25, for the Christmas holiday. * Ahead has 10 passes during the week, seven at 480 kbps, and three at 160 kbps. * Behind starts the week at an SPE angle of 5.2 degrees. Recovery efforts for Behind are Thursday-Saturday, Dec 24-26. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 46: M Nov 09 (313) Ahead: Space weather beacon on NOAA stations resumes 21:55 UT T Nov 10 (314) Ahead: HGA on main lobe, offpoint 1 degree, 240 kbps Ahead: 30 kbps on 34 meter stations W Nov 11 (315) T Nov 12 (316) F Nov 13 (317) S Nov 14 (318) S Nov 15 (319) Ahead: No space weather broadcast following station 43 pass 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. * SECCHI will stop taking images near the end of the day on Nov 15 to assist in the SSR reconfigurations. Images will resume sometime on Nov 16 or 17. * 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 on 70 m Ahead: Uplink array test (DSS-25 & 26) F Nov 20 (324) S Nov 21 (325) Ahead: Return-to-service test 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. * No tracks for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Scheduled activities for Week 48: M Nov 23 (327) Ahead: 96 kbps on 34 meter stations T Nov 24 (328) W Nov 25 (329) T Nov 26 (330) Thanksgiving F Nov 27 (331) S Nov 28 (332) S Nov 29 (333) Notes: * No tracks for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Scheduled activities for Week 49: M Nov 30 (334) Ahead: HGA on main lobe, riding soft stop, 480 kbps Ahead: 120 kbps on 34 meter stations Behind: Resume Behind recovery efforts T Dec 01 (335) W Dec 02 (336) Ahead: Begin No Gyro Operations (NGO) Ahead: First NGO momentum dump, 23:00 UT T Dec 03 (337) F Dec 04 (338) S Dec 05 (339) S Dec 06 (340) ------------------------------------------------------------------------------- Scheduled activities for Week 50: M Dec 07 (341) T Dec 08 (342) W Dec 09 (343) T Dec 10 (344) F Dec 11 (345) Ahead: Return-to-service track with station 34. S Dec 12 (346) S Dec 13 (347) ------------------------------------------------------------------------------- Scheduled activities for Week 51: M Dec 14 (348) Ahead: 160 kbps on 34 meter stations T Dec 15 (349) W Dec 16 (350) T Dec 17 (351) F Dec 18 (352) S Dec 19 (353) S Dec 20 (354) ------------------------------------------------------------------------------- Scheduled activities for Week 52: M Dec 21 (355) Ahead: Momentum dump, 15:30 UT T Dec 22 (356) W Dec 23 (357) T Dec 24 (358) F Dec 25 (359) Christmas S Dec 26 (360) S Dec 27 (361) ------------------------------------------------------------------------------- Upcoming events: Behind events are contingent on recovering the spacecraft. 2015: * Dec 28 Ahead: Main lobe, riding soft stop, 720 kbps (70 m) * 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 * 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 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