STEREO Weekly Meeting Minutes for 2015-12-08 (Week 50) ANNOUNCEMENTS ------------- * None INSTRUMENT and SPACECRAFT STATUS -------------------------------- * Ahead is operating nominally on the main lobe of the high gain antenna with a one degree offset. * There are currently no communications with the Behind spacecraft. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 49 (Nov 30-Dec 6) * On day 335 (Dec 1), during the DSS-63 support for Ahead, turbo decoder lock was lost briefly at 1235z. This anomaly resulted in the loss of 20 frames of real-time and SSR data. * On day 336 (Dec 2), the planned DSS-14 70m support for Ahead was replaced with the ESA Malargüe 35m support to assist the Spitzer mission with their spacecraft anomaly investigation and recovery. As this track change occurred with short notice, a blind acquisition was conducted with the downlink rate at 120 kbps. After the momentum dump was loaded, a transmitter anomaly occurred at 1955z. The anomaly was corrected and the command link was re-established at 2022z. This anomaly resulted in the loss of 6 minutes of SSR data and 27 minutes of tracking data. * On day 338 (Dec 4), the planned DSS-63 support for Ahead was shortened by 40 minutes off the end with a new duration of 2.4 hours to assist the Spitzer mission with their spacecraft anomaly investigation and recovery. * The Ahead observatory operated nominally during this week resuming operations on the HGA main lobe riding along a one degree offset to prevent overheating of the HGA feed assembly which was at 119 degrees C with the HGA angle at 7.1 degrees, with respect to the spacecraft-Sun line. After 15 months of side lobe and superior solar conjunction operations, on day 321, November 17th, nominal daily science operations resumed. * On day 334 (Nov 30), Fault Protection release 2.3.18 and MOps macro 505 were loaded to C&DH RAM and verified. This release contains changes for deploying the No Gyro Operations concept which preserves the remaining IMU lifetime for fault protection use only. * On day 336 (Dec 2), the 82nd momentum dump was executed successfully at 2200z, which imparted an estimated delta V of 0.034 m/sec. (With the IMU off, the delta V can only be estimated.) As this was the first momentum dump that did not use the IMU, a shorter duration was planned by setting the momentum target to zero Nms. G&C lead analysis reported that the dump performance was nominal considering the lack of high rate data. Attitude was well controlled and the star tracker maintained lock throughout the dump. Errors about the Y & Z axes were kept below ~0.5 degrees. However, the X-axis error peaked at ~1.4 degrees during the transition back to wheel control which resulted in intermittent loss of fine pointing for 5.5 hours. * A question was raised about whether the intermittent loss of fine pointing could have been related to the wheels being near zero speed. Although the overall momentum was near zero, the wheel speed avoidance rules were still in effect, and the actual wheel speeds were okay. There were no zero crossings. The excursions when fine pointing was lost were on the order of 10-15 arc seconds. GT lock was never lost. Little effect on the data was seen by the SECCHI COR1 telescope, beyond that which is seen with the IMU turned off--COR1 is particular sensitive to jitter. * On day 339, the SWAVES SSR science partition (#13) filled and began overwriting at 1122z for 6.2 hours and the SECCHI SSR science partition (#19) filled and blocked at 1600z for 1.5 hours. This was primarily due to replacing the 70m support on day 334 with an ESA 35m to support the Spitzer mission with their spacecraft anomaly investigation and recovery. * Processing status of the in-situ instrument space weather data recorded during the 15 months of side lobe operations: The MOC completed processing of the 15 months of in-situ instrument space weather data with the associated data products available on the MOC STEREO Data Server and GSFC SSC websites on day 330, November 26th. However, a final level zero file (.fin version) for each day for each instrument is being created. It is anticipated that this may be done by the end of the week. * The average daily science data return for Ahead, with the HGA on the main lobe riding along a one degree offset, was 4.1 Gbits during this week. * On day 334 (Nov 30), for the DSS-43 support for Behind, the antenna was declared red before the support due to Canberra complex wide switching anomaly. This anomaly resulted in the loss of 4.4 hours of recovery commanding. See DR# C111560 for more information. This was one of the battery conditioning tracks. * On day 334 (Nov 30), during the DSS-14 70m support for Behind, 351 commands were sent for battery state of charge recovery. * On day 336 (Dec 2), during the DSS-14 70m support for Behind, 440 commands were sent for transmitter carrier recovery. The DSN did not detect the downlink signal. While the Allen Telescope Array attempted to observe the Behind observatory concurrently, a configuration issue prevented them from observing. * The fourth uplink array test with Ahead was carried out on Nov 19, using two 34 meter stations, one at 80 kW uplink power, and the other at 20 kW. An increase of 3 dBm was confirmed with the addition of the 20 kW station. The fifth uplink array test is scheduled for Jan 14, with three stations, one at 80 kW and the other two at 20 kW. The resulting power is expected to be twice that of a 70 meter station. The sixth and final test will combine these three stations with the frequency acquisition sequence. Use of uplink arrays with Behind could begin as early as March, depending on DSN resources. It is anticipated that this mode made by used once per month. Week 50 (Dec 7-13) * The station 83 Cebreros pass for Ahead yesterday (Dec 7) had a late acquisition, resulting in the loss of 1.7 hours of telemetry. This prevented PLASTIC from performing their planned commanding, which was moved to the next day (Dec 8). * 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 3.9 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, Friday, and Saturday, Dec 10-12. The Thursday battery conditioning pass will be performed with station 26 transmitting at 80 kW. 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. This rate will persist for the next several years. * Also on Monday, Dec 14, updated fault protection rules 2.3.18 for no-gyro-operations will be written to EEPROM. * Ahead has nine tracks during the week, with seven tracks at 480 kbps, one track at 240 kbps (station 26), 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, while this will be a full dump. The telemetry rate during the track will be 360 kbps. * 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, Friday, and Saturday, Dec 24-26. Week 53 (Dec 28-Jan 3) * On Monday, Dec 28, the downlink rate for 70 meter stations for Ahead will increase to 720 kbps. The HGA will be centered on the main lobe on Dec 30. * APL will be closed on Friday, Jan 1, for the New Year holiday. * Ahead has 10 tracks during the week, and overall coverage is nominal. Six tracks are at 720 kbps, one at 240 kbps, and three at 160 kbps. * Behind starts the week at an SPE angle of 5.7 degrees. Recovery efforts for Behind are Wednesday, Thursday, and Friday, Dec 30-Jan 1. * If Behind is recovered by then, the high gain antenna will be on the main lobe with a 1 degree offset on Jan 2. Week 01 (Jan 4-10) * 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. * 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. 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. The MOC is tuning up the sequence for this roll. It is anticipated that the roll duration will be increased from about 3 hours to 5 hours, with about 10 minutes of additional slew time for each roll step. * Ahead will be at perihelion on Thursday, Jan 14. * The fifth uplink array test is scheduled for Thursday, Jan 14, with stations 24, 25, and 26. The test duration will be about 4 hours. There will be no instrument commanding or SSR playback during this test. * 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. * 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 120 kbps. * 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. * 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. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- 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) ------------------------------------------------------------------------------- Scheduled activities for Week 53: M Dec 28 (362) Ahead: Main lobe, riding soft stop, 720 kbps (70 m) T Dec 29 (363) W Dec 30 (364) Ahead: HGA on main lobe T Dec 31 (365) F Jan 01 (001) New Year S Jan 02 (002) S Jan 03 (003) ------------------------------------------------------------------------------- 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) ------------------------------------------------------------------------------- Upcoming events: Behind events are contingent on recovering the spacecraft. 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 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