STEREO Weekly Meeting Minutes for 2011-04-12 (Week 15) ANNOUNCEMENTS ------------- * None. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * All subsystems on both spacecraft are nominal. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 14 * On day 095 (Apr 5), during the DSS 45 support for Ahead, the pre-pass ranging calibration was unsuccessful due to an anomaly with the uplink ranging assembly. This resulted in uncalibrated ranging data for 235 minutes. See DR# C108011 for more information. * On day 097 (Apr 7), during the DSS 25 support for Ahead, the turbo decoder lost lock intermittently beginning at 1614z. Later, as the station reported a high wind condition, the SSR playback was disabled early at 1740z. This resulted in the loss of 24 frames of instrument SSR data. See DR# N107277 for more information. * On day 098 (Apr 8), during the DSS 14 support for Ahead, initial telemetry lock at BOT was delayed nine minutes due to the antenna pointing model. A conscan was initiated and telemetry lock occurred at 1255z. All SSR data were recovered. See DR# G111326 for more information. * On day 099 (Apr 9), during the DSS 45 support for Ahead, telemetry lock was lost intermittently beginning at 2114z through 2121z due to heavy rain. This resulted in the loss of several minutes of instrument SSR data. See DR# C108022 for more information. * On day 100 (Apr 10), during the DSS 25 support for Ahead, the turbo decoder lost lock intermittently beginning at 1517z through 1540z. This resulted in the loss of several minutes of instrument SSR data. * On day 094 (Apr 4), the playback of SECCHI SSR2, special event partition #20, was enabled on Ahead at 1319z. To optimize downlink bandwidth, after playing back the recorded data, the playback was disabled at 095-1322z (Apr 5). * On day 095 (Apr 5), an additional SECCHI stepped calibration was executed. * On day 097 (Apr 7), the playback of SECCHI SSR2, special event partition #20, was enabled on Ahead at 1314z. To optimize downlink bandwidth, after playing back the recorded data, the playback was disabled at 098-1631z (Apr 8). * On day 099 (Apr 9) at 5:34:20 UT, the PLASTIC high voltage power supply was autonomously disabled on Ahead. It was re-enabled via ground command on day 100 (Apr 10). An anomaly report has been issued. * On day 100 (Apr 10), the star tracker on Ahead reset at 00:20:40z. A t the beginning of the next track with DSS 25, the star tracker was still in standby mode and as designed, fault protection autonomy rule 63 was continuing to fire every 25 seconds to promote it to AAD mode. The ST Failure Recovery contingency procedure was executed which downlinked additional diagnostic data. At 1609z, a soft reset of the star tracker was sent, however, before it reached the S/C, the star tracker successfully promoted to AAD mode via autonomy rule 63 firing. After the OWLT, at 1621z, the soft reset command was executed and the star tracker transitioned back to AAD mode at 1628z. Diagnostic data indicated the reset cause was due to a CPU Error. This was the third star tracker reset on the AHEAD S/C, each of which was due to a CPU error. The first event on Ahead had a similar duration to the present event, but the second event lasted only a few minutes. The event on Behind was longer, and the cause has never been determined. Other missions have seen similar problems with this model star tracker. * On day 094 (Apr 4), during the DSS 24 support for Behind, telemetry lock was lost due to a receiver and DCD equipment overheating anomaly beginning at 1816z through 1826z. This resulted in the loss of an hour of instrument SSR data. See DR# G111308 for more information. * On day 096 (Apr 6), during the DSS 65 support for Behind, turbo decoder lock was lost intermittently beginning at 1644z through 1751z. This resulted in the loss of several minutes of instrument SSR data. See DR# N107274 for more information. * On day 097 (Apr 7), during the DSS 26 support for Behind, turbo decoder lock was lost intermittently beginning at 0221z through 0345z. This resulted in the loss of five frames of instrument SSR data. See DR# N107276 for more information. * On day 098 (Apr 8), during the DSS 26 support for Behind, turbo decoder lock was lost briefly beginning at 0335z. This resulted in the loss of two frames of instrument SSR data. See DR# N107278 for more information. * On day 100 (Apr 10), during the DSS 65 support for Behind, turbo decoder lock was lost intermittently beginning at 1357z through 1524z. This resulted in the loss of 24 frames of instrument SSR data. A DR will be requested for this event. * On day 094 (Apr 4), the playback of SECCHI SSR2, special event partition #20, was enabled on Behind at 1716z. To optimize downlink bandwidth, after playing back the recorded data, the playback was disabled at 096-1715z. * On day 098 (Apr 8), the playback of SECCHI SSR2, special event partition #20, was enabled on Behind at 1835z. To optimize downlink bandwidth, after playing back the recorded data, the playback was disabled at 100-0135z. * The average daily SSR downlink volume was 5.2 gigabits on Ahead, and 5.4 gigabits on Behind. Week 15 * SLE testing will be carried out with the test facility using Ahead simulation data Wednesday (Apr 13) between 15-20 UT. SLE testing took place last week, which went well--this will be additional testing. Instrument teams can expect to see simulation data show up in their realtime telemetry streams unless they restrict themselves to the actual DSN stations being used. * There will be a power outage at APL over the weekend. However, STEREO should be unaffected. In the worst case, some email access may be affected, but BlackBerrys should still work. * Ahead has 720 kbps passes on Monday, Apr 11 (D14), Tuesday, Apr 12 (D43), Wednesday, Apr 13 (D14), Friday, Apr 15 (D14), Saturday, Apr 16 (D14), and Sunday, Apr 17 (D14), for a total of 6 passes. There are in all 9 passes during the week, and overall coverage is nominal. * Behind has no 720 kbps passes during the week. There are 14 passes during the week, and overall coverage is 14.75 hours above nominal. Week 16 * The 31st momentum dump will be carried out on Behind on Wednesday, Apr 20, with ignition at 18:00 UT. * The 37th momentum dump will be carried out on Ahead on Wednesday, Apr 20, with ignition at 21:00 UT. * SLE testing will be carried out for Behind on Tuesday, Apr 19, between 15-20 UT, with Thursday, Apr 21 15-20 UT as a backup. * Ahead has 720 kbps passes on Tuesday, Apr 19 (D43), Wednesday, Apr 20 (D43), Thursday, Apr 21 (D14), and Friday, Apr 22 (D43). There are 11 tracks during the week, and overall coverage is nominal. * Behind has a 720 kbps pass on Thursday, Apr 21 using station D43. There are 15 tracks during the week, and overall coverage is 17.5 hours above nominal. * Easter is on Sunday, Apr 24. Many people at the MOC may be on leave on Friday, Apr 22. Week 17 * The Ahead spacecraft will reach perihelion on Apr 28, and the Behind spacecraft on Apr 29. * There will be a return-to-service track on station 63 for the Behind spacecraft on Apr 29, shadowing a track on station 65. There will be no uplink during this track. * Ahead has 720 kbps passes on Monday, Apr 25 (D43 (twice) and D14), and Tuesday, Apr 26 (D43). There are 11 passes during the week, and overall coverage is nominal. * Behind has 720 kbps passes on Tuesday, Apr 26, and Wednesday, Apr 27, both using station D43. There are 15 passes during the week, and overall coverage is 6 hours above nominal. Week 18 * SECCHI stepped calibration rolls will be carried out on both spacecraft on Tuesday, May 3. The Ahead roll will be at 08:20 UT, and the Behind roll will be at 14:15 UT. These will be the perihelion rolls. The actual dates of perihelion are day 118 (Apr 28) for Ahead, and day 119 (Apr 29) for Behind--the rolls were shifted to May 3 due to system momentum. * There will be a PIT test of ground software version 10.3 using station 25 for Behind on Thursday, May 5. There will be no uplink during this track. * There will be a return-to-service track for Behind on station 24 on Friday, May 6. There will be no uplink during this track. The track will be shadowing station 15. * Ahead has 720 kbps passes on Monday, May 2, Wednesday, May 4, and Sunday, May 8, all using station D14. There are 11 tracks during the week, and overall coverage is nominal. * Behind has a 720 kbps pass on Monday, May 2, using station D43. There are 14 passes during the week, and overall coverage is 9.7 hours above nominal. Week 19 * There is a return-to-service track for station 24 for Ahead on May 9. This will be shadowing a track using station 15. There will be no uplink during this track. * Ahead has a 720 kbps pass on Sunday, May 15, using station D14. There are 14 passes during the week, and overall coverage is nominal. * Behind has 720 kbps passes on Monday, May 9, Tuesday, May 10, Wednesday, May 11, Thursday, May 12, Saturday, May 14, and Sunday, May 15, all using station D63 for a total of six 70 meter passes. There are 14 passes during the week, and overall coverage is 6.8 hours above nominal. Week 20 * Ahead has a 720 kbps pass on Wednesday, May 18 (D63), and Sunday, May 22 (D14). There are 11 passes during the week, and overall coverage is nominal. * Behind has 720 kbps passes on Monday, May 16 (D63), Thursday, May 19 (D63), and Sunday, May 22 (D43), for a total of three 70 meter passes. There are 14 passes during the week, and overall coverage is 2.3 hours above nominal. Week 21 * Ahead has a 720 kbps pass on Thursday, May 26 (D43), and Sunday, May 29 (D63). There are 10 passes during the week, and overall coverage is nominal. * Behind has a 720 kbps pass on Saturday, May 28, using station D63. There are 12 passes during the week, and overall coverage is 5.7 hours above nominal. Week 22 * In preparation for switching to the 160 kbps downlink rate in late June, early July, the DSN time will be increased to 8 hours/day on both spacecraft. * Ahead has 720 kbps passes on Monday, May 30 (D14 and D43), Thursday, Jun 2 (D14 and D43), and Friday, Jun 3 (D63). There are 13 passes during the week, and overall coverage is nominal. * Behind has 720 kbsp passes on Tuesday, May 31 (D63), Wednesday, Jun 1 (D63), Thursday, Jun 2 (D63), Friday, Jun 3 (D63), Saturday, Jun 4 (D63), and Sunday, Jun 5 (D43). There are 10 passes during the week, and overall coverage is nominal. COORDINATED OBSERVATIONS ------------------------ ------------------------------------------------------------------------------- Scheduled activities for Week 14: M Apr 04 (094) Ahead: 720 kbps downlink on station 43 Behind: 720 kbps downlink on station 43 T Apr 05 (095) Ahead: SECCHI stepped calibration roll, 9:00 UT Ahead: Cosmic ray scrub disabled on HI1-A for test, 20-24 UT W Apr 06 (096) T Apr 07 (097) F Apr 08 (098) Ahead: 720 kbps downlink on station 14 S Apr 09 (099) Behind: 720 kbps downlink on station 14 S Apr 10 (100) ------------------------------------------------------------------------------- Scheduled activities for Week 15: M Apr 11 (101) Ahead: 720 kbps downlink on station 14 T Apr 12 (102) Ahead: 720 kbps downlink on station 43 W Apr 13 (103) Ahead: 720 kbps downlink on station 14 Ahead: SLE testing 15-20 UT T Apr 14 (104) F Apr 15 (105) Ahead: 720 kbps downlink on station 14 S Apr 16 (106) Ahead: 720 kbps downlink on station 14 S Apr 17 (107) Ahead: 720 kbps downlink on station 14 ------------------------------------------------------------------------------- Scheduled activities for Week 16: M Apr 18 (108) T Apr 19 (109) Ahead: 720 kbps downlink on station 43 W Apr 20 (110) Ahead: Momentum dump, 21:00 UT Ahead: 720 kbps downlink on station 43 Behind: Momentum dump, 18:00 UT T Apr 21 (111) Ahead: 720 kbps downlink on station 14 Behind: 720 kbps downlink on station 43 F Apr 22 (112) Ahead: 720 kbps downlink on station 43 S Apr 23 (113) S Apr 24 (114) ------------------------------------------------------------------------------- Scheduled activities for Week 17: M Apr 25 (115) Ahead: 720 kbps downlink on stations 43 (twice) and 14 T Apr 26 (116) Ahead: 720 kbps downlink on station 43 Behind: 720 kbps downlink on station 43 W Apr 27 (117) Behind: 720 kbps downlink on station 43 T Apr 28 (118) F Apr 29 (119) Behind: Return-to-service track on D63, shadowing D65 S Apr 30 (120) S May 01 (121) ------------------------------------------------------------------------------- Scheduled activities for Week 18: M May 02 (122) Ahead: 720 kbps downlink on station 14 Behind: 720 kbps downlink on station 43 T May 03 (123) Ahead: SECCHI calibration roll, 08:20 UT Behind: SECCHI calibration roll, 14:15 UT W May 04 (124) Ahead: 720 kbps downlink on station 14 T May 05 (125) Behind: PIT test using station D25, shadowing D15 F May 06 (126) Behind: Return-to-service track on D24, shadowing D15 S May 07 (127) S May 08 (128) Ahead: 720 kbps downlink on station 14 ------------------------------------------------------------------------------- Scheduled activities for Week 19: M May 09 (129) Ahead: Return-to-service track on station D24 Behind: 720 kbps downlink on station 63 T May 10 (130) Ahead: 720 kbps downlink on station 63 Behind: 720 kbps downlink on station 63 W May 11 (131) Behind: 720 kbps downlink on station 63 T May 12 (132) Behind: 720 kbps downlink on station 63 F May 13 (133) S May 14 (134) Behind: 720 kbps downlink on station 63 S May 15 (135) Ahead: 720 kbps downlink on station 14 Behind: 720 kbps downlink on station 63 ------------------------------------------------------------------------------- Scheduled activities for Week 20: M May 16 (136) Behind: 720 kbps downlink on station 63 T May 17 (137) W May 18 (138) Ahead: 720 kbps downlink on station 63 T May 19 (139) Behind: 720 kbps downlink on station 63 F May 20 (140) S May 21 (141) S May 22 (142) Ahead: 720 kbps downlink on station 14 Behind: 720 kbps downlink on station 43 ------------------------------------------------------------------------------- Scheduled activities for Week 21: M May 23 (143) T May 24 (144) W May 25 (145) T May 26 (146) Ahead: 720 kbps downlink on station 43 F May 27 (147) S May 28 (148) Behind: 720 kbps downlink on station 63 S May 29 (149) Ahead: 720 kbps downlink on station 63 ------------------------------------------------------------------------------- Scheduled activities for Week 22: M May 30 (150) Ahead: 720 kbps downlink on stations 14 and 43 T May 31 (151) Behind: 720 kbps downlink on station 63 W Jun 01 (152) Behind: 720 kbps downlink on station 63 T Jun 02 (153) Ahead: 720 kbps downlink on stations 14 and 43 Behind: 720 kbps downlink on station 63 F Jun 03 (154) Ahead: 720 kbps downlink on station 63 Behind: 720 kbps downlink on station 63 S Jun 04 (155) Behind: 720 kbps downlink on station 63 S Jun 05 (156) Behind: 720 kbps downlink on station 43 Notes: * Changing to 8 hours/day of downlink on both spacecraft in preparation for switching to 160 kbps downlink rate in late June, early July. ------------------------------------------------------------------------------- Upcoming events: 2011: * Jun 27 Ahead: Switch downlink rate to 160 kbps * Jun 27 Ahead: End use of 720 kbps on 70 m DSN subnet * Jul 15 Behind: Switch downlink rate to 160 kbps * Jul 15 Behind: End use of 720 kbps on 70 m DSN subnet * Jul 25 Behind: Close approach by comet Elenin * Jul DAWN - Vesta arrival * Jul 13 Both: HGA calibration 2012: * Jan 11 Both: HGA calibration * Jul DAWN - Vesta departure * Jul 11 Both: HGA calibration * Nov 4 Behind: Switch downlink rate to 120 kbps * Nov 13 Total solar eclipse, south Pacific 2013: * May 3 Ahead: Switch downlink rate to 120 kbps * Dec 12 Ahead: Mercury transit 2014: * Jan 20 Behind: End use of 480 kbps on 70 m DSN subnet * Apr 21 Behind: Resume use of 480 kbps on 70 m DSN subnet * Apr 29 Behind: Mercury transit * Oct 15 Behind: End use of 480 kbps on 70 m DSN subnet 2015: * Feb DAWN - Ceres arrival * Jan 20 - Mar 28 (TBC) Behind: Spacecraft behind Sun * Mar 17 - Jul 14 (TBC) Ahead: Spacecraft behind Sun * Jul 2 Behind: Resume use of 480 kbps on 70 m DSN subnet * Aug 25 - Oct 19 (TBC) Behind: Spacecraft behind Sun * Sep 25 Behind: End use of 480 kbps on 70 m DSN subnet * Jul DAWN - End of nominal mission 2016: * Apr 3 Behind: Resume use of 480 kbps on 70 m DSN subnet 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