STEREO Weekly Meeting Minutes for 2015-07-14 (Week 29) ANNOUNCEMENTS ------------- * None. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * Ahead is back to normal operations on the second side lobe. Reaction wheel #3 is currently disabled. * There are currently no communications with the Behind spacecraft. See below for details. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 28 (Jul 6-12) * On day 187 (Jul 6), during the DSS-14 support for Ahead, with the observatory rotating at 5 degrees per minute on the –Z LGA, telemetry lock was never received due to the low signal strength as the LGA is on the edge of the hemispherical pattern. Carrier lock was solid throughout the support with the carrier power between -168 and –177 dBm. * On day 188 (Jul 7), during the DSS-63 support for Ahead, with the observatory rotating at 5 degrees per minute on the +Z LGA, telemetry lock was never received due to the low signal strength as the LGA is on the edge of the hemispherical pattern. Carrier lock was mostly continuous, with occasional drop outs at lower elevation, with the carrier power between -169 and –176 dBm. * On day 189 (Jul 8), during the DSS-14 support for Ahead, after the 35th HCLT initiated system reset with the observatory under 3-axis attitude control again using the 2nd HGA side lobe, telemetry was received nine minutes early at 1341z. RF communications were reasonable with occasional dropouts due to solar interference with a command success rate of 65% and over 76% of the expected telemetry frames received. Due to the effects of solar scintillation, most commands were sent three or more times to ensure reception. * On day 190 (Jul 9), during the DSS-14 support for Ahead, RF communications were reasonable with occasional dropouts due to solar interference with a command success rate of 85% and over 84% of the expected telemetry frames received. Due to the effects of solar scintillation, most commands were sent three or more times to ensure reception. * On day 191 (Jul 10), during the DSS-14 support for Ahead, RF communications were very good with occasional dropouts due to solar interference with a command success rate of 97% and over 98% of the expected telemetry frames received. Due to the effects of solar scintillation, most commands were sent three or more times to ensure reception. * On day 192 (Jul 11), during the DSS-14 support for Ahead, RF communications were very good with occasional dropouts due to solar interference with a command success rate of 98% and over 99% of the expected telemetry frames received. Due to the effects of solar scintillation, most commands were sent three or more times to ensure reception. * On day 193 (Jul 12), during the DSS-14 support for Ahead, RF communications were again surprisingly good with only occasional dropouts due to solar interference with a command success rate of 99% and over 99% of the expected telemetry frames received. * On day 189, July 8th, after the 35th and last HCLT initiated system reset at a 2.0 degree SPE angle, superior solar conjunction exiting recovery operations began. The observatory continued to operate nominally, 3-axis stabilized while communicating on the 2nd HGA side lobe. Commanding to reconfigure the spacecraft bus from solar conjunction exiting began and the following significant activities were completed: - Disabled wheel #3 from G&C control - Increased downlink rate to 3 kbps to flow instrument real-time telemetry (SWAVES as it remains on) - Applied leap second - Spacecraft bus SSR data playback - Loaded and verified track timetags through July 9th The IMPACT and PLASTIC space weather SSR partitions were unchanged, 53.2 and 51.0 percent full respectively, and SWAVES, which has remained on through solar conjunction recording at one packet per minute, is at 51.6 percent full. The HGA feed temperature remains within the predicted range at 114 degrees C. System momentum was at 7.4 Nms and decreasing. As occurred during solar conjunction entry, after the 35th HCLT reset, the star tracker was again “lazy” in re-acquiring a solution causing IMU2 to power on for two hours. G&C reaction wheel #3 continued not responding to G&C torque commands. Further contingency response to this G&C anomaly will be conducted after G&C SSR data is downlinked and analyzed. * On day 190, July 9th, during the track with DSS-14, solar conjunction exiting recovery operations continued with the observatory continuing to operate nominally, 3-axis stabilized while communicating on the 2nd HGA side lobe. The HGA feed temperature remains within the predicted range at 113 degrees C. System momentum is at 7.3 Nms and decreasing. The following significant activities were completed: - Powered on IMPACT IDPU/MAG at 1550z - Powered on IMPACT SEP/SEPT at 1800z - Powered on PLASTIC at 1840z - Continued S/C bus SSR playback of solar conjunction housekeeping - Loaded and verified track timetags through July 19th IMPACT Status - The instruments that we’ve powered on look good (MAG, SIT, HET, LET and SEPT). SWEA and STE are off until we exit the side lobes later in the year. MAG is producing science data which is already being plotted at the SSC. The SEP suite, except for SIT, should be in science mode tomorrow. SIT will up in a few days. * On day 191, July 10th, during the track with DSS-14, solar conjunction exiting recovery operations continued with the observatory continuing to operate nominally, 3-axis stabilized while communicating on the 2nd HGA side lobe. The HGA feed temperature remains within the predicted range at 113 degrees C. System momentum is at 7.3 Nms and decreasing. IMPACT Status - MAG and SEPT have been configured for producing science. (SWEA and STE will remain powered off until we return to the main lobe.) Due to communication interference, efforts to patch LET have been slowed and will continue on day 194. HET is producing some science, but a table load needs to be completed on day 194 to get back to its nominal state. SIT has a bit more configuration to do as well plus its high voltage needs to ramp up so it will be sometime next week before it is producing science. All these instruments appear to be healthy. We’ve seen no anomalous behavior after the long conjunction period so we’re quite happy. PLASTIC Status – began increasing the high voltage and the PAC reached 5 kV S/C C&DH and G&C Housekeeping SSR Data: - C&DH housekeeping = Days 133 and 134 - G&C housekeeping = Days 133 through 137 * On day 192, July 11th, during the track with DSS-14, solar conjunction exiting recovery operations continued with the observatory continuing to operate nominally, 3-axis stabilized while communicating on the 2nd HGA side lobe. The HGA feed temperature remains within the predicted range at 113 degrees C. System momentum is at 7.3 Nms and decreasing. PLASTIC Status – Continued increasing high voltages SECCHI Status – Powered on at 1647z and began recovery. Schedules were loaded and the instrument was in operational mode at 1955z. The spacecraft enabled GT usage and fine pointing was achieved. The spacecraft state was transitioned to operational mode at 2028z. S/C C&DH and G&C Housekeeping SSR Data Return: - C&DH housekeeping = Days 134 and 135-0118z - G&C housekeeping = Days 137 through 145-0736z * On day 193, July 12th, during the track with DSS-14, solar conjunction exiting recovery operations continued with the observatory continuing to operate nominally, 3-axis stabilized while communicating on the 2nd HGA side lobe. The HGA feed temperature remains within the predicted range at 113 degrees C. System momentum is at 7.5 Nms and increasing. PLASTIC Status – Continued increasing high voltages SECCHI Status – After analysis of telemetry today, a table loading error caused the GT data to be invalid near the end of yesterday’s track which led to a false indication and reporting of a SECCHI instrument reset. SECCHI remained in operational mode generating images during the night and the table error was corrected today. SSR partitions percent full status: IMPACT space weather = 54.0 PLASTIC space weather = 51.0 SWAVES space weather = 52.4 S/C C&DH and G&C Housekeeping SSR Data Return: As analysis of the event and anomaly SSR data indicates that the SLVS anomalies began on day 134, the S/C housekeeping SSR read pointers were repositioned to day 133 to begin playing back anomaly data of interest. There are approximately 12 days of interest, and all if goes well, all of this data should be received by next day 196, July 15th. Data downlink today includes: - C&DH housekeeping = Days 135 through 135-0335z - G&C housekeeping = Days 145 through 151-1958z Known Issues: 1. G&C reaction wheel #3, currently disabled, not responding to torque commands. Data is being analyzed as it is received. 2. Preliminary analysis of the SSR anomaly data partitions indicates that 4 soft low voltage shutdowns (SLVS) occurred during solar conjunction. While fault protection recovered the observatory each time, housekeeping data is being analyzed as it is downlinked. As the SLVS response will power down all instruments, SWAVES data will have a gap starting on day 134 for at least 12 days. Week 29 (Jul 13-19) * There is a 70 meter pass for Ahead every day, starting at around 14:00 UT. These passes will be staffed by the MOC. * Ahead starts the week at an SPE angle of 2.2 degrees, on the second side lobe. * New Horizons will make its closest approach to Pluto on Tuesday, Jul 14. However, New Horizons and STEREO do not share views, so this will not have an effect on STEREO coverage. * There are 15 tracks for Ahead during the week. Eleven of these tracks are with 70 meter stations at 3 kbps; the rest are with 34 meter stations at 633 bps. Overall coverage for space weather is 45%. * Behind starts the week at an SPE angle of 3.2 degrees. There will be no passes for Behind during the week. * There was some discussion about the number of Canberra passes for Ahead before the scheduled momentum dump on July 22. * The IMPACT team reports that they have rebooted SIT and LET back into their startup configuration, due to the difficulty of uploading the patches in the current solar weather conditions. Week 30 (Jul 20-26) * Ahead starts the week at an SPE angle of 2.5 degrees, on the second side lobe. * The 78th momentum dump is scheduled for Thursday, Jul 23, with ignition at 21:00 UT. The date was pushed back a few days to allow more time to get an orbital solution after conjunction. * A question was raised about the weekly schedule. An updated schedule should now be available with the correct momentum dump date. * Ahead reaches aphelion on Sun, Jul 26. * Ahead has 21 tracks during the week, with eight 70 meter tracks at 3 kbps, and thirteen 34 meter tracks at 633 bps. There are 70 meter tracks every day, with about 8 hours per track. Total coverage for space weather is 73%. * Behind starts the week at an SPE angle of 3.1 degrees. There will be no passes for Behind during the week. Week 31 (Jul 27-Aug 2) * Ahead starts the week at an SPE angle of 2.8 degrees, on the second side lobe. * Ahead has 18 tracks during the week, with eight 70 meter tracks at 3 kbps, and ten 34 meter tracks at 633 bps. Total space weather coverage is 59%. * Behind starts the week at an SPE angle of 2.9 degrees. There will be no passes for Behind during the week. Behind reaches perihelion on Aug 2. Week 32 (Aug 3-9) * Ahead starts the week at an SPE angle of 3.1 degrees, on the second side lobe. * Ahead has 19 tracks during the week. It is short 8.1 hours of 70 meter time, mostly between Monday to Wednesday, due to critical events for the Juno mission, but there are 70 meter tracks every day. Ten tracks are with 34 meter stations, resulting in 55% space weather coverage during the week. * Behind starts the week at an SPE angle of 2.7 degrees. There will be no passes for Behind during the week. Week 33 (Aug 10-16) * There is a return-to-service track for station 63 on Wednesday, Aug 12. There will be no commanding or SSR playback during this track. * Ahead starts the week at an SPE angle of 3.3 degrees, on the second side lobe. This will be the last week on the second side lobe. * Ahead will shift to the 1st side lobe near the end of the third 70 meter track (station 14) on Sunday, Aug 16. There will be a 34 meter support following this shift, though still at 633 bps. The MOC is monitoring the telemetry margin, and may consider switching to the first side lobe earlier. * Ahead has 17 tracks during the week, nine using 70 meter stations at 3 kbps, and eight using 34 meter stations at 633 bps, giving an overall space weather coverage of 55%. * Behind starts the week at an SPE angle of 2.5 degrees. There will be no passes for Behind during the week. Week 34 (Aug 17-23) * Ahead starts the week at an SPE angle of 3.6 degrees, on the first side lobe. Alternating weeks of IMPACT-prime and SWAVES-prime will resume, starting with IMPACT being prime. * Ahead has 14 passes during the week, with seven passes at 10 kbps, and 7 passes at 633 bps, with overall space weather coverage of 31%. Week 35 (Aug 24-30) * Ahead starts the week at an SPE angle of 3.9 degrees, on the first side lobe, with SWAVES being prime. * Ahead has 19 passes during the week, with seven passes at 10 kbps, and twelve passes at 633 bps, with overall space weather coverage of 39%. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 29: M Jul 13 (194) T Jul 14 (195) W Jul 15 (196) T Jul 16 (197) F Jul 17 (198) S Jul 18 (199) S Jul 19 (200) Notes: * Ahead operating on second side lobe. * No tracks for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Scheduled activities for Week 30: M Jul 20 (201) T Jul 21 (202) W Jul 22 (203) T Jul 23 (204) Ahead: Momentum dump, 21:00 UT F Jul 24 (205) S Jul 25 (206) S Jul 26 (207) Ahead: Aphelion Notes: * Ahead operating on second side lobe. * No tracks for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Scheduled activities for Week 31: M Jul 27 (208) T Jul 28 (209) W Jul 29 (210) T Jul 30 (211) F Jul 31 (212) S Aug 01 (213) S Aug 02 (214) Notes: * Ahead operating on second side lobe. * No tracks for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Scheduled activities for Week 32: M Aug 03 (215) T Aug 04 (216) W Aug 05 (217) T Aug 06 (218) F Aug 07 (219) S Aug 08 (220) S Aug 09 (221) Notes: * Ahead operating on second side lobe. * No tracks for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Scheduled activities for Week 33: M Aug 10 (222) T Aug 11 (223) W Aug 12 (224) Ahead: Return-to-service track with station 63 T Aug 13 (225) F Aug 14 (226) S Aug 15 (227) S Aug 16 (228) Ahead: Switch to first side lobe. Notes: * Ahead operating on second side lobe. * No tracks for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Scheduled activities for Week 34: M Aug 17 (229) T Aug 18 (230) W Aug 19 (231) T Aug 20 (232) F Aug 21 (233) S Aug 22 (234) S Aug 23 (235) Notes: * Ahead operating on the first side lobe, in IMPACT-prime mode. * No tracks for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Scheduled activities for Week 35: M Aug 24 (236) T Aug 25 (237) W Aug 26 (238) T Aug 27 (239) F Aug 28 (240) S Aug 29 (241) S Aug 30 (242) Notes: * Ahead operating on the first side lobe, in SWAVES-prime mode. * No tracks for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Upcoming events: Behind events are contingent on recovering the spacecraft. 2015: * Nov 10 Ahead: HGA on main lobe, offpoint 1 degree, 240 kbps Ahead: SSR playback and reconfiguration, S/C checkout Ahead: Resume space weather broadcast to NOAA stations * Nov 12 Ahead: Instrument recommissioning * Nov 16 Ahead: HGA on main lobe, offpoint 1 degree, 360 kbps Behind: Resume Behind recovery efforts * Nov 20 Behind: HGA on 1st side lobe * Nov 30 Ahead: HGA on main lobe, offpoint 1 degree, 480 kbps * Dec 30 Ahead: HGA on main lobe 2016: * Jan 2 Behind: HGA on main lobe, offpoint 1 degree Behind: SSR playback and reconfiguration, S/C checkout * Jan 5 Behind: Instrument recommissioning * Jan 12 Behind: HGA on main lobe * Jan 27 Both: HGA calibration * Mar 16 Both: Post Solar Conjunction Assessment Review * Jul 5 Juno arrival at Jupiter 2017: * Jul 11 Ahead: Switch downlink rate to 160 kbps * Jul 22 Behind: Switch downlink rate to 160 kbps 2018: * Mar 5 Ahead: Mercury transit 2019: * Mar Ahead: Switch downlink rate to 240 kbps * Apr Behind: Switch downlink rate to 240 kbps 2020: * May Behind: Switch downlink rate to 360 kbps * Jun Ahead: Switch downlink rate to 360 kbps * Jun Behind: Switch downlink rate to 480 kbps * Sep Ahead: Switch downlink rate to 480 kbps 2021: * Jul Behind: Switch downlink rate to 720 kbps * Aug Ahead: Switch downlink rate to 720 kbps