STEREO Weekly Meeting Minutes for 2016-06-07 (Week 23) ANNOUNCEMENTS ------------- * None INSTRUMENT and SPACECRAFT STATUS -------------------------------- * Ahead is operating nominally on the main lobe of the high gain antenna. * There are currently no communications with the Behind spacecraft. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 22 (May 30-Jun 5) * On day 152 (May 31), during the DSS-55 support for Ahead, turbo decoder lock was lost intermittently between 0808z and 0842z. This anomaly resulted in the loss of 5 frames of SSR data. * On day 152 (May 31), during the DSS-25 support for Ahead, turbo decoder was lost intermittently between 2112z and 2124z. This anomaly resulted in the loss of 2 frames of SSR data. * On day 154 (Jun 2), during the DSS-26 support for Ahead, turbo decoder lock was lost briefly at 1853z. This anomaly resulted in the loss of 6 frames of SSR data. * On day 156 (Jun 4), during the DSS-25 support for Ahead, a power glitch at the station resulted in a 14 minute late AOS at 1549z. To avoid SSR data loss, MOps directed the station not to sweep the uplink and remain one-way for the remainder of the support. As a result, 7.1 hours of commanding and two-way tracking data were lost. See DR #G117210 for more information. Also, turbo decoder lock was lost intermittently between 1643z and 1805z. This anomaly resulted in the loss of 3 frames of SSR data. * On day 156 (Jun 4), during the DSS-35 support for Ahead, turbo decoder and telemetry lock were both lost intermittently throughout the entirety of the 3.2 hour support due to heavy rain at the Canberra complex. This anomaly resulted in the loss of 83,314 frames of SSR data. However, all data was recovered on the subsequent day 157 DSS-55 support once SSR pointers were repositioned. See DR #C112099 for more information. * On day 157 (Jun 5), during the DSS-55 support for Ahead, turbo decoder lock was lost intermittently between 0841z and 1030z. This anomaly resulted in the loss of 6 frames of SSR data. * On day 157 (Jun 5), prior to the DSS-26 support for Ahead, the transmitter was declared red. This anomaly resulted in the loss of 9.7 hours of commanding and two-way tracking data. See DR #G117217 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 92 degrees C and decreasing with the HGA angle at 11.7 degrees and increasing, with respect to the spacecraft-Sun line. * On day 152 (May 31), the 88th momentum dump on Ahead was executed successfully at 2000z, which imparted an estimated delta V of 0.095 m/sec. This was the 7th momentum dump that did not use the IMU. After thruster operations completed, there was a 0.82 degree of roll angle error which was dampened out over the next 11 minutes. Fine pointing stabilized 2.4 minutes after completion of the momentum dump. * On day 153 (Jun 1), the SECCHI instrument reset at 06:06:53z. The SECCHI team reconfigured the instrument to operational mode by 2300z. This was the 39th reset of SECCHI on the Ahead observatory. * On day 154 (Jun 2), at 1745z, Fault Protection release 2.3.19 and MOps macro release 1.1.29 were loaded to C&DH EEPROM on Ahead and verified. These releases contain a new autonomy rule for detecting a loss of battery state of charge quicker and commands for correcting a wheel over speed reset condition. * The average daily science data return for Ahead was 5.9 Gbits during this week. * There are no tracks for Behind during the week. The next uplink array attempt is this weekend (Jun 11-12). * Starting in July, attempts to contact Behind will be reduced to once monthly, alternating months between phased uplink array passes, and single-dish passes which have a wider beam. This will continue through June 2017, after which recovery attempts will be suspended until January 2020, when the nominal uplink rate returns to 125 bps. Week 23 (Jun 6-12) * PLASTIC has uploaded time-tagged commands for tomorrow (Jun 8) to adjust some of their science parameters. * Ahead has 10 passes during the week, and overall coverage is nominal. There are four passes at 720 kbps, one pass at 360 kbps, four passes at 240 kbps, and one pass at 160 kbps. * Behind starts the week at an SPE angle of 15.1 degrees. * Uplink array attempts to recover Behind are scheduled for June 11, 12. Each pass will start out with Ahead for 1.9 hours for phase calibration. There will be no instrument calibration or SSR playback during these calibration passes. Following calibration, the stations will attempt to command Behind for 3.3 hours on June 11 for battery recovery, and for 5.3 hours on June 12 for carrier recovery along with station 14. The last 35 minutes will be below the 27.5 degree elevation limit, so a waiver has been requested. Otherwise, the broadcast power would be reduced from 80 to 60 kW. The Allen Telescope Array will also listen for a signal from Behind. * There was some discussion between the MOC and DSN as to whether the radio science receiver would be available for the carrier recovery attempt on Sunday, Jun 12. Week 24 (Jun 13-19) * The STEREO Subsystem Assessment Review is scheduled for 9-11:30 AM EDT on Wednesday, Jun 15. Team members can call into the review using the same telephone number as that used for the weekly telecons. The MOC will also look into setting up a Webex connection. * Ahead has 12 passes during the week, and overall coverage is nominal. There are two passes at 720 kbps, four at 360 kbps, five at 240 kbps, and one at 160 kbps. * Behind starts the week at an SPE angle of 15.1 degrees. There are no tracks for Behind during the week. Week 25 (Jun 20-26) * Ahead has 10 passes during the week, and overall coverage is nominal. There are two passes at 720 kbps, two at 360 kbps, four at 240 kbps, and two at 160 kbps. * Behind starts the week at an SPE angle of 15.2 degrees. Recovery efforts for Behind are Monday-Wednesday, Jun 20-22. The battery recovery tracks will be undertaken with the 80 kW transmitter on station 26. The Allen Telescope Array will listen for a signal Behind spacecraft, along with Arecibo for 1.3 hours. Week 26 (Jun 27-Jul 3) * The 5th battery discharge operation on Ahead is scheduled for Monday, Jun 27, for about 2 hours starting at 17:00. This will be performed during the support, and should not interfere with normal operations. The battery state of charge will be reduced to about 80-85% and assessed, and then reset back to full charge. * Ahead has 12 passes during the week, and overall coverage is nominal. There are three passes at 720 kbps, two at 360 kbps, four at 240 kbps, and three at 160 kbps. * Behind starts the week at an SPE angle of 15.2 degrees. There are no tracks for Behind. Week 27 (Jul 4-10) * Monday, July 4 is a holiday for APL. * Monday, July 4 is aphelion for Ahead. * The 89th momentum dump on Ahead is on Wednesday, Jul 6, at 16:00 UT. This will be the eighth momentum dump without using the gyros. * Ahead has 15 passes during the week, and overall coverage is nominal. There are four passes at 720 kbps, two at 360 kbps, five at 240 kbps, and four at 160 kbps. * Behind starts the week at an SPE angle of 15.1 degrees. There are no tracks for Behind during the week, since recovery attempts are now only once a month. The previously allocated tracks will be returned to the DSN. Week 28 (Jul 11-17) * Ahead has 10 passes during the week, and overall coverage is nominal. There are three passes at 720 kbps, one at 360 kbps, four at 240 kbps, and two at 160 kbps. * Behind starts the week at an SPE angle of 15.1 degrees. * Uplink array attempts for Behind are scheduled for July 16, 17. The first 1.9 hours each day will use the Ahead spacecraft to calibrate the phasing between the stations. There will be no SSR playback or instrument commanding during these passes. Following the calibration, there will be a 3.3 hour pass for Behind on Jul 16 for battery recovery, and a 5.3 hour pass on Jul 17 for carrier recovery. The elevation will drop below 27.5 degrees for the last 48 minutes, so a waiver has been requested; otherwise, the station 26 power would need to be reduced from 80 to 60 kW. Station 14 will listen for the Behind carrier, along with the Allen Telescope Array. Week 29 (Jul 18-24) * The 35th SECCHI stepped calibration roll for Ahead is scheduled for Monday, Jul 18, starting at 13:00 UT. System momentum will be about 6 N-m-s. This is the aphelion roll, and the fourth without using the gyros. * A 3 hour project interface test with the new station 36 at Canberra is scheduled for Wednesday, Jul 20. The new station is expected to be operational sometime later this year. The downlink rate will be 160 kbps, and there will be no SSR playback or instrument commanding during the pass. * Ahead has 12 passes during the week, and overall coverage is nominal. There are three passes at 720 kbps, three at 360 kbps, five at 240 kbps, and one at 160 kbps. * Behind starts the week at an SPE angle of 15.0 degrees. There are no tracks for Behind during the week. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 23: M Jun 06 (158) T Jun 07 (159) W Jun 08 (160) T Jun 09 (161) F Jun 10 (162) S Jun 11 (163) Behind: Phased array recovery attempt S Jun 12 (164) Behind: Phased array recovery attempt ------------------------------------------------------------------------------- Scheduled activities for Week 24: M Jun 13 (165) T Jun 14 (166) W Jun 15 (167) Ahead: STEREO Subsystem Assessment Review T Jun 16 (168) F Jun 17 (169) S Jun 18 (170) S Jun 19 (171) ------------------------------------------------------------------------------- Scheduled activities for Week 25: M Jun 20 (172) T Jun 21 (173) W Jun 22 (174) T Jun 23 (175) F Jun 24 (176) S Jun 25 (177) S Jun 26 (178) ------------------------------------------------------------------------------- Scheduled activities for Week 26: M Jun 27 (179) Ahead: Battery maintenance, 17:00 UT T Jun 28 (180) W Jun 29 (181) T Jun 30 (182) F Jul 01 (183) S Jul 02 (184) S Jul 03 (185) ------------------------------------------------------------------------------- Scheduled activities for Week 27: M Jul 04 (186) Independence Day Ahead: Aphelion T Jul 05 (187) Juno arrival at Jupiter W Jul 06 (188) Ahead: Momentum dump, 16:00 UT T Jul 07 (189) F Jul 08 (190) S Jul 09 (191) S Jul 10 (192) ------------------------------------------------------------------------------- Scheduled activities for Week 28: M Jul 11 (193) T Jul 12 (194) W Jul 13 (195) T Jul 14 (196) F Jul 15 (197) S Jul 16 (198) Behind: Phased array recovery attempt S Jul 17 (199) Behind: Phased array recovery attempt ------------------------------------------------------------------------------- Scheduled activities for Week 29: M Jul 18 (200) Ahead: SECCHI stepped calibration roll, 13:00 UT T Jul 19 (201) W Jul 20 (202) Ahead: Project interface test with station 36 T Jul 21 (203) F Jul 22 (204) S Jul 23 (205) S Jul 24 (206) ------------------------------------------------------------------------------- Upcoming events: Behind events are contingent on recovering the spacecraft. 2016: * 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