STEREO Weekly Meeting Minutes for 2016-01-05 (Week 01) ANNOUNCEMENTS ------------- * None INSTRUMENT and SPACECRAFT STATUS -------------------------------- * Ahead is operating nominally, back on the main lobe of the high gain antenna. * There are currently no communications with the Behind spacecraft. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 53 (Dec 28-Jan 3) * On day 362 (Dec 28), during the DSS-63 support for Ahead, telemetry lock was lost intermittently between 1227z through 1309z due to heavy rain at the Madrid complex. This anomaly resulted in the loss of 3.1 minutes of real-time and SSR data. See DR #M109135 for more information. * On day 001 (Jan 1), during the DSS-63 support for Ahead, telemetry lock was lost intermittently between 0936z through 1009z. This anomaly resulted in the loss of 2 minutes of real-time and SSR data. See DR #M109141 for more information. * On day 003 (Jan 3), during the DSS-65 support for Ahead, turbo decoder lock was lost intermittently between 1543z through 1552z. This anomaly resulted in the loss of 115 frames of real-time and SSR data. * On day 003 (Jan 3), during the DSS-43 support for Ahead, telemetry lock was lost intermittently between 2044z through 2108z due to heavy rain at the Canberra complex. This anomaly resulted in the loss of 1.2 minutes of real-time and SSR data. See DR #C111648 for more information. * The Ahead observatory operated nominally during this week on the center of the HGA main lobe. The HGA feed assembly was at 119 degrees C with the HGA angle at 7.1 degrees, with respect to the spacecraft-Sun line. From this point on, the temperature should start to slowly come down. * On day 362 (Dec 28), the prime science downlink rate of 720 kbps was resumed during 70m supports as the HGA returned to the center of the main lobe for daily communications. The rate on 34 meter stations will remain at 160 kbps for the next two years. * The average daily science data return for Ahead was 4.2 Gbits during this week. * On day 364 (Dec 30), during the DSS-43 70m support for Behind, 225 commands were sent for battery state of charge recovery. * On day 365 (Dec 31), during the DSS-14 70m support for Behind, 189 commands were sent for battery state of charge recovery. * On day 001 (Jan 1), during the DSS-14 70m support for Behind, 440 commands were sent for transmitter carrier recovery. The DSN did not detect the downlink signal. Due to the duration of the support and the increased commands for each step, only 22 of the 36 frequency segments were commanded. Three commands must be received sequentially to power on the transmitter. * The SSC reports that a computer glitch prevented SECCHI beacon images from being processed from Jan 2 to the morning of Jan 4, though data from the other instruments continued to be processed. * SECCHI reports that a scheduling anomaly prevented any images from being taken on Jan 3. The same anomaly also occured on Dec 24. Week 01 (Jan 4-10) * Turbo decoder lock was lost intermittently yesterday (Jan 4) during the station 63 pass for Ahead, starting at 10:21 UT and lasting for approximately an hour. The reason is not clear, as the link margin was good. * Ahead has 10 tracks during the week, and overall coverage is nominal. There are four tracks at 720 kbps, two at 240 kbps, and four at 160 kbps. * Behind starts the week at an SPE angle of 6.2 deg. Recovery efforts for Behind are Monday, Tuesday, and Wednesday, Jan 4-6. The battery recovery tracks will be performed with the 80 kW transmitter on station 26. The Allen Telescope array will listen in during the carrier recovery track tomorrow (Jan 6). Week 02 (Jan 11-17) * The 32nd SECCHI stepped calibration roll on Ahead is tentatively scheduled for Tuesday, Jan 12, starting at 12:30 UT, depending on both the MOC and SECCHI being ready. This will be the first stepped roll without the IMU. System momentum is expected to be about 4 N-m-s. The duration of the calibration roll be about 4.5 hours. * SECCHI reports that the scheduling anomalies that they experienced on Dec 24 and Jan 3 will prevent them from supporting the calibration roll unless corrected. They are investigating the cause, and hope to solve the problem by the end of the week. The MOC wil load up the commands for the roll tomorrow, but these can be cancelled. SECCHI will inform the MOC by Friday whether or not they are ready to go ahead with the roll. * Ahead will be at perihelion on Thursday, Jan 14. * The fifth uplink array test is scheduled for Thursday, Jan 14, with stations 24 and 25 at 20 kW, and station 26 at 80 kW. The received power at the satellite is expected to be roughly twice that of a 70 meter station. The test duration will be about 4 hours. There will be no instrument commanding or SSR playback during this test. The uplink rate will be 7.8 bps during the test, and downlink will be non-coherent. * A question was raised about what resources will be used for downlink when the phased uplink array is used to try to recover Behind, perhaps as early as March. The 70 meter station 14, also at Goldstone, will be used for downlink. Since this means that four stations will be used simultaneously, this configuration will be scheduled only about once per month. Only the carrier recovery tracks will use the phased array configuration. These tracks will be 6.5 hours long. The battery recovery tracks will be 4.5 hours long, and will use a single station, either 70 meter or station 26 at 80 kW. Other non-DSN assets will also be used to listen for the Behind carrier: the Allen Telescope Array, Green Bank, and Arecibo. Behind will be visible from Arecibo during only part of the year, roughly from April to August. * Ahead has 9 passes during the week, and overall coverage is nominal. There are five passes at 720 kbps, one at 240 kbps, and three at 160 kbps. * Behind starts the week at an SPE angle of 6.7 degrees. Recovery efforts for Behind are Friday, Saturday, and Sunday, Jan 11-17. The first two tracks will be undertaken with station 26 using the 80 kW transmitter. Week 03 (Jan 18-24) * A 2.6 hour ranging test with station 15 with Ahead will be carried out on Monday, Jan 18. There will be no instrument commanding or SSR playback during this test. The telemetry rate will be 160 kbps. * The 84th momentum dump for Ahead is scheduled for Thursday, Jan 21, with ignition at 23:00 UT. The telemetry rate will be 160 kbps. The telemetry performance during the previous dump on Dec 21 was very good. * Ahead has 10 passes during the week, and overall coverage is nominal. There are four passes at 720 kbps, two passes at 240 kbps, and four passes at 160 kbps. * Behind starts the week at an SPE angle of 7.2 deg. Recovery efforts for Behind are Monday, Tuesday, and Wednesday, Jan 18-20. The Tuesday pass will be undertaken with station 26 using the 80 kW transmitter. Week 04 (Jan 25-31) * Ahead has 11 passes during the week, and overall coverage is nominal. There are two passes at 720 kbps, three passes at 240 kbps, and six passes at 160 kbps. * Behind starts the week at an SPE angle of 7.7 degrees. Recovery efforts for Behind are Wednesday, Thursday, and Saturday, Jan 20-23. The first two tracks will be undertaken with station 26 using the 80 kW transmitter. Week 05 (Feb 1-7) * Ahead has 10 passes during the week, and overall coverage is nominal. There are three passes at 720 kbps, three passes at 240 kbps, and four passes at 160 kbps. * Behind starts the week at an SPE angle of 8.3 degrees. Recovery efforts for Behind are Monday, Tuesday, and Thursday, Feb 1-4. The battery recovery tracks will be undertaken with the 80 kW transmitter on station 26. Week 06 (Feb 8-14) * Ahead has 12 passes during the week, and overall coverage is nominal. There are four passes at 720 kbps, two passes at 240 kbps, and six passes at 160 kbps. * Behind starts the week at an SPE angle of 8.8 degrees. Recovery efforts for Behind are on Friday, Saturday, and Sunday, Feb 12-14. The battery recovery tracks will be undertaken with the 80 kW transmitter on station 26. * Behind will be at aphelion on Friday, Feb 12. Week 07 (Feb 15-21) * The final uplink array test with Ahead will be carried out on Feb 19. This will combine the previously tested phased array of stations 24, 25 at 20 kW, and station 26 at 80 kW, with the frequency segmented acquisition mode for recovering Behind. Combining array phasing with the frequency segmented acquisition mode is very challenging. If this test works, then it will be ready for use with the Behind recovery efforts, possibly in March. The uplink rate will be 7.8 bps, and the downlink will be non-coherent. There will be no instrument commanding or SSR playback during the test. * Ahead has 9 passes during the week, and overall coverage is nominal. There are four passes at 720 kbps, two at 240 kbps, and three at 160 kbps. * Behind starts the week at an SPE angle of 9.4 degrees. Recovery efforts for Behind are on Friday, Saturday, and Sunday, Feb 19-21. The battery recovery track on Saturday will be carried out with the 80 kW transmitter on station 26. Other * A question was raised about future scheduling of HGA calibration maneuvers. It has been decided to discontinue HGA calibrations, since no problems have ever been detected. This can be revisited if future problems arise. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 01: M Jan 04 (004) T Jan 05 (005) W Jan 06 (006) T Jan 07 (007) F Jan 08 (008) S Jan 09 (009) S Jan 10 (010) ------------------------------------------------------------------------------- Scheduled activities for Week 02: M Jan 11 (011) T Jan 12 (012) Ahead: First NGO SECCHI stepped calib. roll 12:30 (TBC) W Jan 13 (013) T Jan 14 (014) Ahead: Perihelion Ahead: Uplink array test with stations 24,25,26 F Jan 15 (015) S Jan 16 (016) S Jan 17 (017) ------------------------------------------------------------------------------- Scheduled activities for Week 03: M Jan 18 (018) Ahead: Ranging test with station 15 T Jan 19 (019) W Jan 20 (020) T Jan 21 (021) Ahead: Momentum dump, 23:00 UT F Jan 22 (022) S Jan 23 (023) S Jan 24 (024) ------------------------------------------------------------------------------- Scheduled activities for Week 04: M Jan 25 (025) T Jan 26 (026) W Jan 27 (027) T Jan 28 (028) F Jan 29 (029) S Jan 30 (030) S Jan 31 (031) ------------------------------------------------------------------------------- Scheduled activities for Week 05: M Feb 01 (032) T Feb 02 (033) W Feb 03 (034) T Feb 04 (035) F Feb 05 (036) S Feb 06 (037) S Feb 07 (038) ------------------------------------------------------------------------------- Scheduled activities for Week 06: M Feb 08 (039) T Feb 09 (040) W Feb 10 (041) T Feb 11 (042) F Feb 12 (043) Behind: Aphelion S Feb 13 (044) S Feb 14 (045) ------------------------------------------------------------------------------- Scheduled activities for Week 07: M Feb 15 (046) T Feb 16 (047) W Feb 17 (048) T Feb 18 (049) F Feb 19 (050) Ahead: Uplink array test with stations 24,25,26 S Feb 20 (051) S Feb 21 (052) ------------------------------------------------------------------------------- Upcoming events: Behind events are contingent on recovering the spacecraft. 2016: * 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 Behind: HGA on main lobe * 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