STEREO Weekly Meeting Minutes for 2015-12-01 (Week 49) ANNOUNCEMENTS ------------- * The momentum dump for Dec 2 has been moved forward one hour. See below for details. 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 48 (Nov 23-29) * On day 330 (Nov 26), during the DSS-63 support for Ahead, turbo decoder lock was lost intermittently between 1107z and 1118z. This anomaly resulted in the loss of 14 frames of real-time and SSR data. * On day 333 (Nov 29), during the DSS-43 support for Ahead, the track ended 1.6 hours early at 2208z due to Canberra complex wide switching anomaly. The MOC disabled the SSR early; however, the station stopped tracking seven minutes before the RTLT completed. This anomaly resulted in the loss of 6-7 minutes of SSR data--equivalent to up to 49 minutes of observation time--and 1.6 hours of commanding and tracking data. See DR# C111552 for more information. * 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 and increasing, with respect to the spacecraft-Sun line. The temperature is expected to remain near 119 degrees until the end of the year. After 15 months of side lobe and superior solar conjunction operations, on day 321, November 17th, nominal daily science operations resumed. * On day 327 (Nov 23), the G&C parameters, version 1.3.4, release was loaded to C&DH EEPROM on Ahead. The release contained changes for returning to nominal daily science operations that are already in use in RAM. All G&C parameters were dumped from RAM and EEPROM for verification. * On day 329 (Nov 25), the SWAVES SSR science partition (#13) on Ahead filled and began overwriting at 0249z for 18.1 hours. On day 331, SWAVES record rate was decreased to 1.746 kbps (rate C) at 2000z to preserve data continuity. It's anticipated that SWAVES can raise their rate again at the end of the year. * Processing status of the in-situ instrument space weather data recorded during the 15 months of side lobe operations: This week, the MOC has 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. However, a final level zero file (.fin version) for each day for each instrument is being created. * The average daily science data return for Ahead, with the HGA on the main lobe riding along a one degree offset, was 3.5 Gbits during this week. * Operations to recover the Behind spacecraft resumed this week. Green Bank will assist in the recovery efforts periodically, as their schedule permits. STEREO Behind is currently below the view of the Arecibo telescope until April. * The last uplink array test with Ahead, on Nov 19, combined two 34 meter stations, one broadcasting at 80 kW and the other broadcasting at 20 kW. A 3 dB increase in signal was seen with the two stations combined, compared to the 80 kW station alone. The next test is scheduled for Jan 14, which will involve three Goldstone stations, two at 20 kW and one at 80 kW. The resulting signal is expected to be twice the strength of a 70 meter station. Week 49 (Nov 30-Dec 6) * The station 43 antenna was still red for the scheduled Behind battery conditioning track late on Sunday into early Monday (Nov 29/30), so that track did not occur. * On Monday, Nov 30, updated fault protection release 2.3.18 (no gyro operations release) was written to RAM on Ahead. * The 82nd momentum dump for Ahead is scheduled for Dec 2, with ignition at 22:00 UT, one hour earlier than originally scheduled. 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 360 kbps to maintain telemetry lock in case the pointing varies during the dump. * The timing of this momentum dump was moved forward by one hour--it was originally scheduled for 23:00 UT--to assist the Spitzer mission with a spacecraft anomaly. This is a very late change to the schedule. New weekly schedules reflecting the change will be available later in the afternoon. Instruments will have an opportunity to command before the momentum dump. There was some discussion about how this will affect the SECCHI instrument. The instrument doors will close automatically at the beginning of the momentum dump, based on a signal from the spacecraft. The SECCHI schedule currently ends at 22:00 UT, so only a few images should be affected. If SECCHI is unable to get new commands up, operations will simply begin as originally scheduled, which will be an hour later than strictly necessary. Currently, SECCHI is having problems with scheduling observations sooner than 24 hours in advance. * The new pass for the momentum dump will be a blind acquisition, so the MOC will command the telemetry rates and the SSR playback at the beginning of the pass. * Turbo decoder lock was lost intermittently during the station 63 pass for Ahead this morning (Dec 1), resulting in the loss of about 20 frames of telemetry. * Tomorrow's pass for Behind, starting at 15:25 UT, will attempt to recover the carrier wave. Green Bank will not be participating in this pass. * 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 increased to 480 kbps on Monday, Nov 30. * Ahead has 7 passes during the week, and overall coverage is nominal. Six passes are at 480 kbps, and one pass is at 120 kbps (for the momentum dump). * Behind starts the week at an SPE angle of 3.9 degrees. 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 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. * 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. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- 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) ------------------------------------------------------------------------------- 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 Ahead: First NGO SECCHI stepped calib. roll (date TBC) Behind: HGA on main lobe * Jan 14 Ahead: Uplink array test * 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