STEREO Weekly Meeting Minutes for 2014-09-09 (Week 37) ANNOUNCEMENTS ------------- * None. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * All subsystems on both spacecraft are nominal. Ahead is operating on the first side lobe of the HGA to prevent overheating of the feed assembly. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 36 (Sep 1-7) * On day 244 (Monday, Sep 1), during the DSS-26 support, the star tracker in Behind reset at 1544z. After the star tracker failed to promote back to AAD mode, fault protection powered on the IMU-A at 1545z. At 1721z, the telemetry lock was lost due to a very weak signal from inaccurate HGA pointing due to the loss of the star tracker data and contingency operations were suspended. The star tracker never returned to AAD mode for the remainder of the track and the last 1.5 hours of the track were lost. Later in the day, the Behind space weather beacon images provided insight that perhaps the star tracker anomaly had cleared. On day 245, during the DSS-54 support, the star tracker was back in AAD mode after fault protection had successfully promoted it at 244-2026z. IMU-A was powered off at 1102z after being on for 19.5 hours. SSR pointers were repositioned and all SSR data was recovered. This was the second star tracker reset on the Behind observatory since launch. * On day 244 (Monday, Sep 1), the star tracker on STEREO Ahead had reset at 1528z, 16 minutes before the Behind star tracker anomaly. The STEREO space weather data provided a strong indication that an X-class solar flare was the cause of the star tracker resets on both observatories. After the star tracker failed to promote back to AAD mode, fault protection powered on IMU-B at 1529z. With the star tracker unavailable, due to the low pointing allowance while on the first side lobe, during the next support with DSS-63 on day 245 (Sep 2), telemetry lock was established at 0902z, 2.7 hours late. No op commands were sent to reset the 60 hour soft command loss timer. The star tracker never returned to AAD mode for the remainder of the track. On day 246 (Sep 3), during a contingency support with the ESA Malargüe station, DSS-84, the star tracker was back in AAD mode after fault protection had successfully promoted it at 245-1010z. The star tracker was in Standby mode for 18.7 hours. IMU-B was powered off at 1220z after being on for 44.2 hours. This was the 5th star tracker reset on the Ahead observatory since launch. * On day 245 (Tuesday, Sep 2), during the DSS-84 contingency support for the Ahead star tracker recovery, side lobe communications were tested with an ESA 35 meter station, Malargüe, with the Ahead observatory. At the low downlink rate of 633 bps and 12 degrees elevation, there was ~6 dB downlink margin on the first side lobe. Commanding was successful at 125 bps. The downlink configuration of the observatory was then switched to 3 kbps and while the station locked successfully to telemetry at an 36.9 degrees elevation, there was very little margin, i.e., at lower elevations or any adverse weather, telemetry lock could not be maintained. The project considers the ESA stations viable for emergency use as well as occasional spacecraft bus checks at the low downlink rate of 633 bps. * On day 245 (Tuesday, Sep 2), during the DSS-43 track for Behind, turbo decoder lock was lost briefly at 2158z. SSR pointers were re-positioned and all SSR data was received. * On day 245 (Sep 2), G&C parameters version 1.3.1 were loaded to G&C EEPROM on Behind in preparations for Behind solar conjunction testing to commence on day 270. * On day 246 (Wednesday, Sep 3), during the DSS-14 support for Ahead, initial reception of telemetry in the MOC as delayed two minutes until 1527z due to a transmitter calibration anomaly. Later in the support, the MOC lost real-time telemetry, commanding, and monitor data due to a link anomaly at the station at 1717z. The communications link was restored and SLE command and telemetry binds were re-established at 1730z. These anomalies resulted in the loss of 13 minutes of rea l-time telemetry and commanding. See DRs #G115420 and #G115422 for more information. * On day 246 (Sep 3), during the DSS-54 support for Behind, initial receipt of telemetry in the MOC was delayed 2.5 hours until 1018z due to a network anomaly at APL caused by an undetected brown-out condition. The RIONet connectivity was restored and the MOC rebound to SLE telemetry server. All SSR data was received. * On day 241 (Aug 29), during the DSS-43 support for Ahead, after the 71st momentum dump completed, the prime real-time telemetry rate for SWAVES, 0.4606 kbps, decreased to its non-prime rate of 0.0726 kbps. This was caused by the RTDFD table used for monitoring the momentum dump to fill the SWAVES science queue with a wider range of APIDs then switching to the SWAVES prime RTDFD which throttles the SWAVES APIDs. This resulted in the certain APIDs blocking the SWAVES science queue. On day 251 (Sep 8), the SWAVES science queue was emptied by using a higher downlink rate RTDFD. Something similar may have happened with SECCHI APIDs. * On day 247 (Sep 4), the SECCHI instrument on Behind reset at 18:16:16z. The SECCHI team reconfigured the instrument to operational mode at 1730z. This was the 23rd reset of SECCHI on the Behind spacecraft. * The average daily SSR playback volume this week was 0.080 Gbits Ahead (operating on the first side lobe) and 3.4 Gbits on Behind Week 37 (Sep 8-14) * On Ahead on Monday, Sep 8th, during the DSS-25 support, first side lobe communications were tested at the 1 kbps and 3 kbps downlink rates with a DSN 34 meter station. At the 3 kbps downlink rate using the XHEMT receiver, while carrier and symbol lock were achieved, the signal level was too low for telemetry lock even at higher elevations. At 1551z, the station switched to the maser receiver and telemetry lock was achieved with ~1.5 dB of downlink margin at high elevation. An SSR playback of the spacecraft data was conducted. At 1732z, the 1 kbps downlink rate was tested with ~7 dB downlink margin on the first side lobe and ~2 dB on the second side lobe. Commanding was successful on at 125 and 500 bps. * On Monday, Sep 8, PLASTIC performed realtime commanding to adjust MCP voltages. * On Wednesday, Sep 10, on Behind mission ops macros and DFD associated with them will be loaded into RAM for 10 kbps downrate. * Ahead has 7 passes during the week, all at 10 kbps on the first side lobe, in SWAVES-prime mode. * Behind has 12 passes during the week, and overall coverage is nominal. There are two passes at 720 kbps, two passes at 160 kbps, and eight passes at 120 kbps. Week 38 (Sep 15-21) * On Monday Sep 15 fault protection release versions 2.3.14 and 2.3.15 for EEPROM on Behind will be loaded. * On Tuesday Sep 16 the latest mission ops macros (1.24) for C&DH RAM to EEPROM will be uploaded to Behind, and EA mode bypass will be enabled. * There will be a test readiness review on Thursday, Sep 18, for the Behind testing. * Ahead has 7 passes during the week, all at 10 kbps on the first side lobe, in IMPACT-prime mode. * Behind has 13 passes during the week, and overall coverage is nominal. There are two passes at 720 kbps, four passes at 160 kbps, and seven passes at 120 kbps. Week 39 (Sep 22-28) * Solar conjunction testing for Behind will start on Saturday, Sep 27. A more detailed schedule has been distributed. Instruments will be turned off by 18 UT, with the exception of SWAVES which will remain on. SWAVES will be powered cycled twice during the test. POC queues will be open on Friday for instrument commanding. Testing will include reconfiguration of the SSR. * On Sunday, Sep 28, the HGA angle bias will be switched to the first side lobe. The 67th momentum dump will be carried out during the station 14 pass on the first side lobe, starting at 16:30 UT, with a lower target of 8 N-m-s as will be used during solar conjunction. The commands for the momentum dump will be loaded during the previous pass. The spacecraft will be commanded to reset at 17:30 UT, and will come up at 633 bps, and slowly rotating at 5 degrees/minute. * Ahead has 7 passes during the week, all at 10 kbps on the first side lobe, in SWAVES-prime mode. * Behind has 13 passes during the week, and overall coverage is nominal. There are two passes at 720 kbps, four passes at 160 kbps, and seven passes at 120 kbps. ESA New Norcia passes are scheduled for Monday, Sep 22, and Wednesday, Sep 24. Week 40 (Sep 29-Oct 5) * A momentum dump on Ahead will be carried out on Tuesday, Sep 30, with ignition at 22:00 UT. The commands for the momentum dump will be loaded during the previous pass. * Solar conjunction testing on Behind will continue during the week. The earlier testing on Ahead concentrated on the process of going into solar conjunction. These tests will concentrate on the process of coming out. The recorder is also reconfigured during these tests, which was not done during the Ahead testing. * During the first pass on Monday, Sep 29, the MOC will watch the spacecraft rotate. At 05:30 UT a macro will put the spacecraft into 3-axis stabilized mode. * On Tuesday, Sep 30, the 48 hour fault protection rule will trigger at 17:30 UT, switching to the -Z LGA. * On Wednesday, Oct 1, Behind the soft command load timer will trigger at 5:30 UT, switching to the +Z LGA, and start the spacecraft slowly rotating. Station 14 will acquire the signal at 15:30, at 12 bps, and will watch the spacecraft rotate. At 17:50, the 3 day hard command loss timer will trigger, resetting the spacecraft, and setting it back to 3 axis stabilized on the second side lobe. It will then be commanded to a 1 degree offset at 120 kbps, and spacecraft will be reconfigured back to operational mode. * On Thursday, Oct 2, the spacecraft will come up at a 1 degree offset, and will be commanded back to the center of the main lobe. Instrument power on is expected to begin during the station 36 support starting at 15:30 UT. An ESA New Norcia support is also available later in the day, as well as another DSN support and an ESA New Norcia support on Friday. The remainder of the passes during the week will be using 70 meter stations. * Ahead has 9 passes during the week, all at 10 kbps on the first side lobe, in IMPACT-prime mode. * Behind has 13 passes during the week, and overall coverage is nominal. There are three passes at 720 kbps, one pass at 160 kbps, six passes at 120 kbps, two passes at 0.633 kbps, and one pass at 0.012 kbps. ESA passes have been scheduled for Thursday and Friday, Oct 2-3. Week 41 (Oct 6-12) * Ahead has seven passes during the week, all at 10 kbps on the first side lobe, in SWAVES prime mode. * Behind has 13 passes during the week, and overall coverage is nominal. There are five passes at 720 kbps, two passes at 160 kbps, and six passes at 120 kbps. An ESA New Norcia pass is scheduled for Thursday, Oct 9. Week 42 (Oct 13-19) * The 30th SECCHI step-calibration for Behind is on Tuesday, Oct 14 (orbit mid-point) starting at 12:00 UT. * Ahead has nine passes during the week, eight are regular DSN passes at 10 kbps. There will also be an additional ESA pass with New Norcia on Thursday Oct. 17. There will be no science coming down on this track and, because it is only 1.3 hours long, probably not enough time to send commands. All commanding is on the on the first side lobe, in IMPACT prime mode. * Behind has 12 passes during the week, and overall coverage is nominal. There are three passes at 720 kbps, three passes at 160 kbps, and six passes at 120 kbps. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 37: M Sep 08 (251) T Sep 09 (252) W Sep 10 (253) T Sep 11 (254) F Sep 12 (255) S Sep 13 (256) S Sep 14 (257) Notes: * Ahead operating on first side lobe, in SWAVES-prime mode. * Passage of Comet Siding Spring through HI2 on Behind, Sep 07-Nov 15 ------------------------------------------------------------------------------- Scheduled activities for Week 38: M Sep 15 (258) T Sep 16 (259) W Sep 17 (260) T Sep 18 (261) F Sep 19 (262) S Sep 20 (263) S Sep 21 (264) MAVEN arrival at Mars Notes: * Ahead operating on first side lobe, in IMPACT-prime mode. * Passage of Comet Siding Spring through HI2 on Behind, Sep 07-Nov 15 ------------------------------------------------------------------------------- Scheduled activities for Week 39: M Sep 22 (265) T Sep 23 (266) W Sep 24 (267) T Sep 25 (268) F Sep 26 (269) S Sep 27 (270) Behind: Instruments off for solar conjunction testing, 18 UT (except SWAVES) S Sep 28 (271) Behind: Switch to first side lobe. Momentum dump, 16:30 UT. Spacecraft reset at 17:30 UT, come up at 633 bps, rotating 5 degrees/minute. Notes: * Test of solar conjunction operations on Behind, Sep 27-Oct 3 * Ahead operating on first side lobe, in SWAVES-prime mode. * Passage of Comet Siding Spring through HI2 on Behind, Sep 07-Nov 15 ------------------------------------------------------------------------------- Scheduled activities for Week 40: M Sep 29 (272) Behind: Solar conjunction testing continues Behind: Timed command to 3-axis stabilized, 5:30 UT T Sep 30 (273) Behind: Switch to -Z LGA, 17:30 UT Ahead: Momentum dump, 22:00 UT W Oct 01 (274) Behind: Switch to +Z LGA and start rotating, 5:30 UT Hard command loss timer, 17:50, switch to 3 axis stab. Switch from 2nd side lobe to 1 degree offset, 120 kbps T Oct 02 (275) Behind: Command back to 0 degree offset on main lobe. Recover spacecraft, start powering instruments back on. F Oct 03 (276) Behind: Continue recovery as needed S Oct 04 (277) S Oct 05 (278) Notes: * Test of solar conjunction operations on Behind, Sep 27-Oct 3 * Ahead operating on first side lobe, in IMPACT-prime mode. * Passage of Comet Siding Spring through HI2 on Behind, Sep 07-Nov 15 ------------------------------------------------------------------------------- Scheduled activities for Week 41: M Oct 06 (279) T Oct 07 (280) W Oct 08 (281) T Oct 09 (282) F Oct 10 (283) S Oct 11 (284) S Oct 12 (285) Notes: * Ahead operating on first side lobe, in SWAVES-prime mode. * Passage of Comet Siding Spring through HI2 on Behind, Sep 07-Nov 15 ------------------------------------------------------------------------------- Scheduled activities for Week 42: M Oct 13 (286) T Oct 14 (287) Behind: 30th SECCHI step-calibration W Oct 15 (288) T Oct 16 (289) F Oct 17 (290) Behind: Comet Siding Spring encounter with Mars S Oct 18 (291) S Oct 19 (292) Notes: * Ahead operating on first side lobe, in IMPACT-prime mode. * Passage of Comet Siding Spring through HI2 on Behind, Sep 07-Nov 15 ------------------------------------------------------------------------------- Upcoming events: 2014: * Sep 07-Nov 15 Behind: Passage of Comet Siding Spring through HI2-B * Oct 23 Both: Solar Conjunction Readiness Review * Nov 10 Ahead: HGA on 2nd side lobe * Nov 17 Ahead: Test with 34 meter at 633 bps * Nov 19 Behind: HGA hits soft stop * Nov 28 Behind: SSR reconfiguration * Dec 1 Behind: HGA on 1st side lobe * Dec 8 Behind: Test with 34 meter at 633 bps, both side lobes 2015: * Jan 6 Behind: HGA on 2nd side lobe * Jan 12 Behind: Test with 34 meter at 633 bps * Jan 20 Behind: Instrument power down * Jan 22 - Mar 23 Behind: Spacecraft behind Sun * Mar DAWN - Ceres arrival * Mar 22 Ahead: Instrument power down * 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 * Sep 24 Ahead: HGA on 1st side lobe * Nov 20 Behind: HGA on 1st side lobe * Dec 29 Ahead: HGA on main lobe, offpoint 1 degree Ahead: SSR playback and reconfiguration, S/C checkout * Dec 31 Ahead: Instrument recommissioning 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 * Feb 19 Ahead: HGA on main lobe * 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