STEREO Weekly Meeting Minutes for 2014-07-22 (Week 30) ANNOUNCEMENTS ------------- * none INSTRUMENT and SPACECRAFT STATUS -------------------------------- * All subsystems on both spacecraft are nominal. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 29 (Jul 14-20) * On day 195 (Jul 14), DSS-63 declared the receiver orange due to an issue with the cryogenic system. This anomaly degraded the downlink signal by 10 dB, resulting in the loss of real-time telemetry and ranging data for the duration of the 3.4 hour support of Behind. This anomaly resulted in the loss of up to 20 hours of SSR data for some instruments. See DR #M108153 for more information. * On day 195 (Jul 14), the IMPACT SIT instrument on Ahead successfully ramped up the high voltage to science configuration level. * On day 196 (Jul 15), during the DSS-84 support for Ahead, a parameter was loaded to G&C RAM to enable GT rates usage at 1647z. This corrected the intermittent loss of fine pointing that had been occurring since the spacecraft was recovered from the system reset practiced during solar conjunction testing on day 192. This G&C parameter had been inadvertently omitted due to mission evolution of the reset recovery operations last executed in 2009. The standby mode reset recovery procedure has been updated accordingly. * On day 196 (Jul 15), the 29th SECCHI stepped calibration on Behind was executed at 0435z for the perihelion in the orbit. * On day 196 (Jul 15), the 20th HGA Calibration on Behind was successfully executed at 1300z. * On day 197 (Jul 16) APL-18m station successfully supported the tracking, recording, processing, and transmitting of the space weather broadcast from each observatory (Ahead and Behind) to the SSC at GFSC. * On day 197 (Jul 16), during the DSS-65 support for Ahead, turbo decoder lock was lost briefly at 0805z. This anomaly resulted in the loss of one frame of SSR data. * On day 198 (Jul 17), a connectivity test on Ahead was conducted with DSS-35, the new 34m BWG antenna at the DSN Canberra complex, was successfully conducted at 2150z. The MOC successfully bound with telemetry server and with the station for commanding, received spacecraft telemetry with a good SNR, and sent 31 commands to the station only, from all three MOC command workstations. * On day 199 (Jul 18), during the DSS-63 support for Behind, turbo decoder lock was lost briefly at 1230z. This anomaly resulted in the loss of 16 frames of SSR data. * On day 200 (Jul 19), during the DSS-15 support for Ahead, turbo decoder lock was intermittent for the 4.6 hour duration of the support due to elevation encoder anomaly at the station. This anomaly resulted in the loss of 23,983 frames of SSR data (about half an hour). See DR #G115245 for more information. * On day 201 (Jul 20), during the DSS-55 support for Behind, turbo decoder lock was lost briefly at 1237z. This anomaly resulted in the loss of four frames of SSR data. * The average daily SSR playback volume during this week was 5.2 Gbits for Ahead and 4.7 GBits for Behind. Week 30 (Jul 21-27) * Starting on Wednesday, Jul 23, a 3 hour project interface test (PIT) with the new 34 meter station D35 at Canberra will be carried out with Behind. There will be no instrument commanding or SSR playback during this pass. * On Sunday, Jul 27, a return-to-service pass with station 26 will be carried out. There will be no instrument commanding or SSR playback during this pass. * There will be a commercial power outage at the MOC on Saturday, July 26. This is not expected to affect operations. * Ahead has 10 passes during the week, and overall coverage is nominal. 70 meter passes are scheduled for Tuesday, Jul 22 (D63 at 720 kbps), Wednesday, Jul 23 (D14), Friday, Jul 25 (D14 at 720 kbps), Saturday, Jul 26 (D43), and Sunday, Jul 27 (D14 at 720 kbps). The following passes will be carried out at 160 kbps: Monday, Jul 21 (D54), Thursday, Jul 24 (D55), Saturday, Jul 26 (D54), and Sunday, Jul 27 (D55). * Behind has 12 passes during the week, and overall coverage is nominal. 70 meter passes are scheduled for Monday, Jul 21 (D43 at 720 kbps and D63), Tuesday, Jul 22 (D14 at 720 kbps), Wednesday, Jul 23 (D14 at 720 kbps), Friday, Jul 25 (D63), and Saturday, Jul 26 (D14 at 720 kbps). The following passes will be carried out at 160 kbps: Thursday, Jul 24 (D54), Friday, Jul 25 (D24), Saturday, Jul 26 (D55), and Sunday, Jul 27 (D54). Week 31 (Jul 28-Aug 3) * The HGA angle on Ahead is expected to reach the soft stop on July 28. After this, the telemetry signal will start to drift off the center of the main lobe, and the achievable telemetry rate will start to drop. During week 32, the maximum telemetry rate will still be 720 kbps. This drops to 480 kbps in week 33, and 360 kbps in week 34, after which the spacecraft will switch to side lobe 1. There are two 34 meter supports during week 32 which will be at 96 kbps, on Aug 6 and 9. After that, only 70 meter supports will be used. * C&DH flight software version 3.2.4 will be written to EEPROM copy 1 on Ahead on Jul 29. * The 65th momentum dump on Behind will be carried out on Jul 28, with ignition at 19:45 UT. This is earlier than usual due to schedule constraints. * A 3 hour Project Interface Test (PIT) will be carried out on Behind with station 35 on Jul 30. There will be no instrument commanding or SSR playback during this pass. * The RF margin using the 70 meter stations has been reevaluated, and it has been determined that the 720 kbps rate can be used routinely when on the main lobe. From this point on, this rate will be used for all Behind passes until the HGA soft stop limit is reached. * Ahead has 10 passes during the week, and overall coverage is nominal. There is one pass at 720 kbps, one pass at 480 kbps, one pass at 240 kbps, six passes at 160 kbps, and one pass at 120 kbps. * Behind has 10 passes during the week, and overall coverage is nominal. There are five passes at 720 kbps, and five passes at 120 kbps. Week 32 (Aug 4-10) * The 70th momentum dump on Ahead will be carried out on Aug 4, with ignition at 18:00 UT. * Ahead has 10 passes during the week, and overall coverage is nominal. There are seven passes at 720 kbps, one pass at 240 kbps, and two passes at 96 kbps, on Aug 6 and 9. * Behind has 10 passes during the week, and overall coverage is nominal. There are five passes at 720 kbps, three passes at 240 kbps, one pass at 160 kbps, and one pass at 120 kbps. Week 33 (Aug 11-17) * The 4th battery discharge/charge cycle on Behind will be Aug. 14. This will not affect science operations. * Ahead will be at aphelion on Saturday, Aug 16. It has not yet been decided whether a SECCHI stepped calibration roll will be performed. * Ahead has 8 passes during the week, all at 480 kbps, and overall coverage is nominal. * Behind has 13 passes during the week, and overall coverage is nominal. There are three passes at 720 kbps, one pass at 240 kbps, two passes at 160 kbps, and seven passes at 120 kbps. Week 34 (Aug 18-24) * The Ahead reconfiguration for side-lobe operations will be loaded on Tuesday Aug. 19th. Final mission operation macros and the HDA angle bias will be loaded. Ahead operations on the first side lobe will start Aug 20th. * Ahead has 8 passes during the week, and overall coverage is nominal. There are two passes at 360 kbps (Monday and Tuesday). On Aug 20th first side lobe coverage will begin and be at 10 kbps. This will continue until around Nov. 10 when operations on the second side lobe will bring this down to 3 kbps. * Behind has 14 passes during the week, with nominal coverage overall. Three tracks are at 720 kbps, one at 160 kbps and nine at 120 kbps. Week 35 (Aug 25-31) * Ahead will be operating with the high gain antenna on its first side lobe. * The 66th momentum dump for Behind is Monday, Aug 25 at 18:30 UT. * Ahead has 7 passes, all at 10 kbps, for nominal coverage. * Behind has 11 passes during the week, and overall coverage is nominal. Six passes are at 720 kbps, one at 240 kbps, two at 160 kbps and two at 120 kbps. Other * APL is continuing to look through data from the solar conjunction testing on Ahead. During the testing, on day 188 (Jul 7), after the commanded system reset to simulate solar conjunction entry, when the star tracker finally promoted to AAD mode, it incorrectly provided attitude solutions for approximately three minutes. This offpointed the spacecraft by 75 degrees. The star tracker corrected itself and the G&C resumed nominal sun pointing. A similar anomaly has occurred with same star tracker on the MESSENGER mission. * Current high gain antenna temperatures are Ahead: 111 C, at a STE angle of 8.3 degrees Behind: 104 C at a STE angle of 8.9 degrees Behind is several degrees hotter than predicted and Ahead several degrees cooler. This may lead to some refinements in scheduled dates for side-lobe operations. * To protect the HGA feed from excessive heating, the STEREO AHEAD observatory will begin side lobe operations on August 20th. While side lobe operations allow for daily communications, instrument science CONOPs changes to use the very reduced data rates for real-time science reception and recording critical science for the duration of the side lobe and solar conjunction periods. As the MOC and spacecraft were not designed for instrument use at the 10 kbps and 3 kbps downlink rates, a Side Lobe Real-time Telemetry Downlink Rate Test is being considered to test these new real-time telemetry configurations before they are required on August 20th. Additionally, the new flight RTDFD tables cannot be tested as is using the MOC hardware simulator (flatsat) as the simulator cannot generate the required low rates of instrument telemetry packets. COORDINATED OBSERVATIONS ------------------------------------------------------------------------------- Scheduled activities for Week 29: M Jul 14 (195) Ahead: IMPACT/SIT HV ramp-up complete T Jul 15 (196) Behind: SECCHI stepped calibration roll, 04:35 UT Behind: HGA calibration, 13:00 UT W Jul 16 (197) T Jul 17 (198) Ahead: Project interface test with new 34 meter station D35 F Jul 18 (199) S Jul 19 (200) S Jul 20 (201) ------------------------------------------------------------------------------- Scheduled activities for Week 30: M Jul 21 (202) T Jul 22 (203) W Jul 23 (204) T Jul 24 (205) Behind: Project interface test with new 34 meter station D35 F Jul 25 (206) S Jul 26 (207) S Jul 27 (208) Behind: Return-to-service test with D26 ------------------------------------------------------------------------------- Scheduled activities for Week 31: M Jul 28 (209) Behind: Momentum dump, 19:45 UT T Jul 29 (210) W Jul 30 (211) Behind: Project interface test with new 34 meter station D35 T Jul 31 (212) F Aug 01 (213) S Aug 02 (214) S Aug 03 (215) Notes: * Ahead is expected to reach the soft stop on the HGA angle on July 28. The telemetry rate will slowly drop after this. ------------------------------------------------------------------------------- Scheduled activities for Week 32: M Aug 04 (216) Ahead: Momentum dump, 18:00 UT T Aug 05 (217) W Aug 06 (218) T Aug 07 (219) F Aug 08 (220) S Aug 09 (221) S Aug 10 (222) ------------------------------------------------------------------------------- Scheduled activities for Week 33: M Aug 11 (223) T Aug 12 (224) W Aug 13 (225) T Aug 14 (226) Ahead: Solar Conjunction Readiness Review F Aug 15 (227) S Aug 16 (228) Ahead: Aphelion S Aug 17 (229) ------------------------------------------------------------------------------- Scheduled activities for Week 34: M Aug 18 (230) T Aug 19 (231) W Aug 20 (232) Ahead: Beginning of operations on 1st side lobe. T Aug 21 (233) F Aug 22 (234) S Aug 23 (235) S Aug 24 (236) ------------------------------------------------------------------------------- Scheduled activities for Week 35: M Aug 25 (237) Behind: Momentum dump, 18:30 UT. T Aug 26 (238) W Aug 27 (239) T Aug 28 (240) F Aug 29 (241) S Aug 30 (242) S Aug 31 (243) ------------------------------------------------------------------------------- Upcoming events: 2014: * Aug 20 Ahead: Instrument power down * Aug 23 Ahead: HGA on 1st side lobe * Sep 07-Nov 15 Behind: Passage of Comet Siding Spring through HI2-B * Sep 18 Behind: MOps Readiness for S/C Testing Review * Sep 29-Oct 6 Behind: Test of solar conjunction operations * Sep 21 MAVEN arrival at Mars * Oct 17 Behind: Comet Siding Spring encounter with Mars * Oct 20 Ahead: Instrument power on * Oct 23 Behind: Solar Conjunction Readiness Review * Nov 10 Ahead: HGA on 2nd side lobe * Nov 19 Behind: HGA hits soft stop * Dec 1 Behind: HGA on 1st side lobe 2015: * Jan 6 Behind: HGA on 2nd side lobe * 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 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 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