STEREO Weekly Meeting Minutes for 2016-05-10 (Week 19) 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 18 (May 2-8) * On day 124 (May 3), during the DSS-26 support for Ahead, turbo decoder lock was lost briefly at 125-0049z. This anomaly resulted in the loss of one frame of SSR data. * On day 125 (May 4), during the DSS-55 support for Ahead, turbo decoder lock was lost briefly at 0849z and again at 0908z. This anomaly resulted in the loss of 3 frames of SSR data. * On day 126 (May 5), during the DSS-26 support for Ahead, a power glitch at the station during pre-track calibration activities resulted in a late uplink sweep. Data lost due to the late sweep were recovered as all SSR pointers were repositioned once the uplink was established. See DR# G117085 for more information. Two subsequent power glitches occurred at 1655z and 2127z. SSR pointers were again repositioned following both anomalies. See DR#s G117089 and G117094 for more information. Telemetry and command binds were dropped from 1850z through 1859z due to a network glitch between Goddard and JPL. See DR# N110284 for more information. These anomalies resulted in the loss of only a few frames of SSR data. * On day 127 (May 6), during the DSS-25 support for Ahead, the maser receiver was declared red at BOT. Since the station could not consistently hold turbo decoder lock on the scheduled 240 kbps downlink using the XHEMT receiver, MOps commanded the downlink to 160 kbps, with lock occurring at 1632z. Once the uplink was established, all SSR pointers were repositioned and the SSR restarted at the 160 kbps downlink rate. See DR# G117100 for more information. A power glitch at the station resulted in a loss of the services between 2051z and 2149z. SSR pointers were again repositioned following the anomaly. These anomalies resulted in the loss of only a few frames of SSR data. See DR# G117101 for more information. * On day 128 (May 7), during the DSS-65 support for Ahead, turbo decoder lock was lost briefly at 1142z. This anomaly resulted in the loss of one frame of SSR data. * On day 128 (May 7), during the DSS-14 Return to Service engineering demonstration support with Ahead, there was no SSR playback or instrument commanding. During the setup period, the station reported that the microwave interface was not working. The BOT/AOS was delayed by 13 minutes and the uplink by 20 minutes. DR# G117121 was opened to document the problem. The downlink was acquired successfully. All 4 CLTUs sent were received successfully by the spacecraft. Conscan was enabled after the 2-way mode with the observed offsets of 1.8 mdeg in AZ and 1.0 mdeg in XEL indicating that DSS-14's pointing model was good. * On day 128 (May 7), during the DSS-35 support for Ahead, turbo decoder lock was lost briefly at 129-0339z. This anomaly resulted in the loss of one frame of SSR data. * On day 129 (May 8), during the DSS-55 support for Ahead, telemetry lock was lost intermittently between 0817z and 1452z due to heavy rain at the Madrid complex. This anomaly resulted in the loss of 3648 frames of real-time and SSR data, which is the equivalent of about 2-3 minutes. See DR# M109348 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 101 degrees C and decreasing with the HGA angle at 10.5 degrees and increasing, with respect to the spacecraft-Sun line. * The average daily science data return for Ahead was 5.5 Gbits during this week. * There were no tracks for Behind during the week. Week 19 (May 9-15) * Telemetry lock was intermittent for about 2 hours during the station 45 pass for Ahead early Monday, May 9, due to heavy rain in Canberra. This resulted in the loss of several minutes worth of data. * The 34th SECCHI stepped calibration roll on Ahead was carried out successfully yesterday (May 9). * Turbo decoder lock was lost briefly during the station 24 pass yesterday for Ahead, resulting in the loss of 19 frames of data. * Later this week, the MOC will be loading new C&DH fault protection rules and macros to RAM. These changes are designed to provide better protection in case of the loss of one of the reaction wheels, or low solar array voltage. * There are some changes in the DSN schedule later in the week, to accommodate maintenance work to address the power problems that the Goldstone complex has been experiencing. The station 26 pass on Thursday, May 12, has been shortened from 9.75 hours to 5.4 hours, and an additional station 35 pass of 3 hours has been added for Friday, May 13. These changes will appear in the Weekly Schedule shortly. * Behind starts the week at an SPE angle of 14.4 degrees. Phased uplink array passes for Behind recovery are scheduled for May 13 and 14. The first 1.9 hours each day will be with Ahead to calibrate the antenna phasing. There will be no instrument commanding or SSR playback during these calibration passes. These passes with Ahead show up in the DSN schedules, so the NOAA antenna partners will know when Ahead will or will not be in space weather broadcast mode. The subsequent pass durations for Behind will be 3.2 hours on May 13 for battery recovery, and 5.3 hours on May 14 for carrier recovery. The last ~40 minutes will be below 27.5 degrees elevation, so a waiver has been requested; otherwise, the broadcast power would be decreased from 80 to 40 kW. The Allen Telescope array will listen for any signal from Behind, along with DSN station 14. These passes will be attended within the MOC. * Ahead has 13 tracks during the week, and overall coverage is nominal. There are three tracks at 720 kbps, two at 360 kbps, five at 240 kbps, and three at 160 kbps. Week 20 (May 16-22) * Ahead has 13 tracks during the week, and overall coverage is nominal. There are two tracks 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 14.6 degrees. There are no tracks for Behind during the week. Week 21 (May 23-29) * Electrical maintenance will be carried out at the MOC during Memorial Day weekend. During this time, the MOC will be on generator power, starting at 5:00 PM EDT on Friday, May 27, through 8:00 PM EDT on Monday, May 30. Operations will not be affected. * Ahead has 14 tracks during the week, and overall coverage is nominal. There are three tracks at 720 kbps, seven at 240 kbps, and four at 160 kbps. * Behind starts the week at an SPE angle of 14.8 degrees. Recovery efforts for Behind are on Friday-Sunday, May 27-29. The battery recovery tracks will be undertaken with the 80 kW transmitter on station 26. The Allen Telescope Array will also be listening during the transmitter recovery track, along with station 14. Week 22 (May 30-Jun 5) * Monday, May 30, is Memorial Day, which is an APL holiday. * The 88th momentum dump on Ahead will be carried out on Tuesday, May 31, with ignition at 20:00 UT. This will be the seventh momentum dump without using the gyros. * Jun 2, the MOC will be loading new C&DH fault protection rules and macros to EEPROM. These changes are designed to provide better protection in case of the loss of one of the reaction wheels, or low solar array voltage. * Ahead has 12 passes during the week, and overall coverage is nominal. There are two passes at 720 kbps, three at 360 kbps, five at 240 kbps, and two at 160 kbps. * Behind starts the week at an SPE angle of 15.0 degrees. There are no passes for Behind during the week. Week 23 (Jun 6-12) * Ahead has 9 passes during the week, and overall coverage is nominal. There are 4 passes at 720 kbps, one pass at 360 kbps, three 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 will be requested. Otherwise, the broadcast power would be reduced from 80 to 60 kW. Week 24 (Jun 13-19) * 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 on 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 batter recovery tracks will be undertaken with the 80 kW transmitter on station 26. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 19: M May 09 (130) Ahead: SECCHI stepped calibration roll, 12:00 UT T May 10 (131) W May 11 (132) T May 12 (133) F May 13 (134) Behind: Phased array recovery attempt S May 14 (135) Behind: Phased array recovery attempt S May 15 (136) ------------------------------------------------------------------------------- Scheduled activities for Week 20: M May 16 (137) T May 17 (138) W May 18 (139) T May 19 (140) F May 20 (141) S May 21 (142) S May 22 (143) ------------------------------------------------------------------------------- Scheduled activities for Week 21: M May 23 (144) T May 24 (145) W May 25 (146) T May 26 (147) F May 27 (148) S May 28 (149) S May 29 (150) ------------------------------------------------------------------------------- Scheduled activities for Week 22: M May 30 (151) Memorial Day T May 31 (152) Ahead: Momentum dump, 20:00 UT W Jun 01 (153) T Jun 02 (154) F Jun 03 (155) S Jun 04 (156) S Jun 05 (157) ------------------------------------------------------------------------------- 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) ------------------------------------------------------------------------------- Upcoming events: Behind events are contingent on recovering the spacecraft. 2016: * 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