STEREO Weekly Meeting Minutes for 2015-01-27 (Week 05) ANNOUNCEMENTS ------------- * None. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * Ahead is operating on the second side lobe of the HGA to prevent overheating of the feed assembly. * There are currently no communications with the Behind spacecraft. See below for details. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 04 (Jan 19-25) * On day 021 (Jan 21), during the DSS-43 support for Ahead, turbo decoder lock was lost intermittently between 0422z through 0427z due to heavy rain at the Canberra complex. This anomaly resulted in the loss of 77 frames of real-time data. See DR# C110899 for more information. * On day 021 (Jan 21), a flight software patch to the G&C application RAM was successfully loaded and verified on Ahead. This patch will prevent bad IMU data flagged by the IMU as good from being used by the G&C application. * On day 023 (Jan 23), on PLASTIC tested the entrance system of PLASTIC-A at 2010z to determine the cause of an increasing power supply current indication. * On day 024 (Jan 24), SECCHI-A began downlinking real-time space weather images at BOT minus 15 minutes during second side lobe operations. * The average daily science data return this week for Ahead, while operating on the second side lobe on the HGA, was 18 Mbits. * On day 025 (Jan 25), the DSS-63 support for Ahead at 0835z did not occur as the antenna was declared red due to a mechanical anomaly. This anomaly resulted in the loss of 1.9 hours of commanding, tracking, and real-time data. See DR# M108538 for more information. * On days 022 through 025 (Jan 22-25), during the DSN 70 meter supports for Behind, recovery commanding was conducted to ensure that the transmitter is in its operational configuration. No signal was received by the DSN radio science receivers. * On day 022 (Jan 22), the Behind observatory entered superior solar conjunction at the 2 degree SPE angle. Recovery efforts will resume post solar conjunction on day 075 with increasing the ground transmit power through arraying uplink stations and implementing the Failure Review Board recommendations. * Significant findings to date: 1. Analysis of the three DSN extracted telemetry frames from the carrier signal just before the planned observatory reset/anomaly occurred on day 2014-274, October 1st, showed nominal performance of the spacecraft, i.e., no anomalies, IMU off, and the star tracker providing an attitude solution. 2. Post reset, from the very limited telemetry, three packets, extracted from the carrier signal by the DSN, the X-axis gyro on IMU-A had failed. Unfortunately, this telemetry contained only G&C anomaly data and no spacecraft summary data, i.e., the state of the RF, G&C, fault protection and other subsystems is not known at the time of the anomaly. With a failed IMU and the star tracker being offline for an undetermined duration, the sun sensors will keep the observatory pointed at the Sun, though the G&C will not have any roll knowledge, and cannot roll the observatory as part of the safing configuration to reestablish communications on the LGAs. From analysis of this telemetry and initial G&C simulations, it is highly suspected that the observatory is rotating about the principal axis of inertia due to an autonomous momentum dump initiated by bad gyro data flagged good, but this has not yet been confirmed. 3. At least two anomalies occurred post reset, the star tracker not promoting to AAD mode and the X-axis gyro failure. Unfortunately, due to the number of possible combinations, the STEREO fault protection system is not designed for simultaneous failures. Week 05 (Jan 26-Feb 01) * On day 25-26 (Jan 26-27) no data was returned during the ESA New Norcia support. There were no problems with the subsequent pass using a different station. New Norcia had not been used before on the 2nd side lobe, and it is thought this was a problem with the signal being too faint. * A dry run for the Solar Conjunction Readiness Review will be held on Jan 29, 8:30 am. The review itself is scheduled for Feb 12. * Ahead has 15 passes during the week, seven at 3 kbps, and eight at 633 bps. Overall 70 meter coverage is short about 6.2 hours. * No passes are scheduled for Behind due to superior solar conjunction. Week 06 (Feb 2-8) * DSCOVR first launch opportunity Sunday, Feb. 8 at 23:10 UT. * On Wednesday, Feb 4, the restricted IONet at APL will be down for maintenance for four hours starting at 15:00 UT. This should not effect operations, as there are no passes during this time. * Ahead has 8 passes during the week, seven at 3 kbps, and one at 633 bps. Overall 70 meter coverage is about 6.5 hours short, mainly between Monday to Thursday, along with 2 hours on Saturday. An ESA Malargue pass was added on Monday, Feb 2, to help fill in the gap. * No passes are scheduled for Behind due to superior solar conjunction. Week 07 (Feb 9-15) * The 76th momentum dump on Ahead is scheduled for Tuesday, Feb 10, starting at 15:30 UT. * The solar conjunction readiness review is scheduled for Thursday, Feb 12, starting at 8:30 A.M at APL. * Ahead has 7 passes during the week, all at 3 kbps. The perviously scheduled 34 meter passes are allocated for DSCOVR Overall 70 meter coverage is short about 7 hours spread throughout the week. * No passes are scheduled for Behind due to superior solar conjunction. Week 08 (Feb 16-22) * Ahead has 7 passes during the week, six at 3 kbps one at 633 bps. Overall coverage is short 4.5 hours between Tuesday to Sunday. * No passes are scheduled for Behind due to superior solar conjunction. Week 09 (Feb 23-Mar 1) * Daylight saving time begins in continental US at 07:00 UT on March 1. * Ahead has 7 passes during the week, all at 3 kbps. Overall coverage is short 4.25 hours between Monday-Thursday. * No passes are scheduled for Behind due to superior solar conjunction. Week 10 (Mar 2- 8) * On Wednesday Mar 4 at 14:00 UT the restricted IONet at APL will be taken down while the prime router is replaced. * Ahead has 8 passes during the week, seven at 3 kbps, one at 633 kbps. Coverage is even * No passes are scheduled for Behind due to superior solar conjunction. Week 11 (Mar 9-15 ) * Thursday Mar 12 during overlapping tracks for 34 m stations 24 and 25 there will be an uplink array test. There will be no commanding during this time. * Ahead has 12 passes during the week, six at 3 kbps, six at 633 kbps. Coverage is short 4 hours M-W * No passes are scheduled for Behind due to superior solar conjunction. Other: * There has been difficulty during the 2nd side-lobe operations in downloading the spacecraft housekeeping data from times outside of ground contact. As a result, the MOC will be extending its playback time from the current 75 minutes to the duration of the 70 meter tracks. * The dates for Ahead's return to the 1st side-lobe and main lobe operations will be sooner than previously expected. Ahead will return to 1st side lobe operations on Aug. 17 and main lobe on Nov. 10. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 05: M Jan 26 (026) T Jan 27 (027) W Jan 28 (028) T Jan 29 (029) Solar Conjunction Readiness Review dry run. F Jan 30 (030) S Jan 31 (031) S Feb 01 (032) Notes: * Ahead operating on second side lobe. * No passes for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Scheduled activities for Week 06: M Feb 02 (033) T Feb 03 (034) W Feb 04 (035) T Feb 05 (036) F Feb 06 (037) S Feb 07 (038) S Feb 08 (039) Notes: * Ahead operating on second side lobe. * No passes for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Scheduled activities for Week 07: M Feb 09 (040) T Feb 10 (041) Ahead: Momentum dump, 15:30 UT W Feb 11 (042) T Feb 12 (043) Solar Conjunction Readiness Review F Feb 13 (044) S Feb 14 (045) S Feb 15 (046) Notes: * Ahead operating on second side lobe. * No passes for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Scheduled activities for Week 08: M Feb 16 (047) T Feb 17 (048) W Feb 18 (049) T Feb 19 (050) F Feb 20 (051) S Feb 21 (052) S Feb 22 (053) Notes: * Ahead operating on second side lobe. * No passes for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Scheduled activities for Week 09: M Feb 23 (054) T Feb 24 (055) W Feb 25 (056) T Feb 26 (057) F Feb 27 (058) S Feb 28 (059) S Mar 01 (060) Notes: * Ahead operating on second side lobe. * No passes for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Scheduled activities for Week 10: M Mar 02 (061) T Mar 03 (062) W Mar 04 (063) T Mar 05 (064) F Mar 06 (065) S Mar 07 (066) S Mar 08 (067) Notes: * Ahead operating on second side lobe. * No passes for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Scheduled activities for Week 11: M Mar 09 (068) T Mar 10 (069) W Mar 11 (070) T Mar 12 (071) F Mar 13 (072) S Mar 14 (073) S Mar 15 (074) Notes: * Ahead operating on second side lobe. * No passes for Behind due to superior solar conjunction. ------------------------------------------------------------------------------- Upcoming events: Behind events are contingent on recovering the spacecraft. 2015: * Jan 22 - Mar 23 Behind: Spacecraft behind Sun * Feb 12 Solar Conjunction Readiness Review * Mar DAWN - Ceres arrival * Mar 22 Ahead: Instrument power down (except SWAVES) * Mar 23 - Apr 06 Behind: S/C SSR Playback at 3 kbps * Mar 24 - Jul 07 Ahead: Spacecraft behind Sun * Mar 30 Behind: Instrument power on * Apr 25 Behind: HGA on 1st side lobe * Jul DAWN - End of nominal mission * Jul 8 Behind: HGA on 2nd side lobe * Jul 7-28 Ahead: S/C SSR Playback at 3 kbps * Jul 14 Ahead: Instrument power on * Aug 17 Ahead: HGA on 1st side lobe * Nov. 10 Ahead: HGA on main lobe, offpoint 1 degree Ahead: SSR playback and reconfiguration, S/C checkout * Nov 12 Ahead: Instrument recommissioning * Nov 20 Behind: HGA on 1st side lobe * Dec 30 Ahead: HGA on main lobe 2016: * Jan 2 Behind: HGA on main lobe Behind: SSR playback and reconfiguration, S/C checkout * Jan 5 Behind: Instrument recommissioning * 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