STEREO Weekly Meeting Minutes for 2010-10-05 (Week 40) ANNOUNCEMENTS ------------- * The internet will be shut down for 10 minutes on Wednesday, Oct 6, starting at 23:30 UT. The instrument teams will lose connectivity during this time. There are no tracks during this period. * The restricted IONet at APL will be upgraded during week 41. See below for details. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * All subsystems on both spacecraft are nominal. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 39 * On day 270 (Sep 27), during the DSS 63 support for Ahead, turbo decoder lock was lost briefly at 05:14 UT due to an equipment anomaly at the station. This resulted in the loss of three frames of SECCHI SSR data. See DR# N106560 for more information. * On day 272 (Sep 29), before BOT of the DSS 63 support for Ahead, real-time telemetry and monitor data were lost due to a network equipment anomaly at JPL. This resulted in the loss of 56 minutes of real-time telemetry, monitor, and command services. All SSR data were received. * On day 275 (Oct 2), before the start of the DSS 45 support for Ahead, the transmitter was declared red. The support was moved to DSS 43 for its entirety. Subsequently, monitor data was lost for 89 minutes beginning at 18:06 UT. All SSR data was recovered. See DR# N106584 for more information. * On day 276 (Oct 3), during the DSS 55 support for Ahead, turbo decoder lock was lost briefly at 08:27 UT. This resulted in the loss of one frame of SECCHI SSR data. * On day 276 (Oct 3), DSS 25 was declared red before the start of the support for Ahead. The support was moved to DSS 15; however, the end of track was 10 minutes early. This resulted in the loss of approximately 30 minutes of instrument SSR data. Station 25 continued to be down, causing additional problems along the line. * The average daily SSR playback was 6.5 gigabits for Ahead, and 4.7 gigabits for Behind. * On day 270 (Sep 27), during the DSS 54 support for Behind, the command bind aborted due to a network anomaly connecting JPL to the station at 15:39 UT, 16:52 UT, and 18:44 UT. While the station maintained a 2-way link, SECCHI instrument commands were transmitted 10 minutes later than their planned time. All SSR data were recovered. * On day 271 (Sep 28), during the DSS 54 support for Behind, the command bind aborted due to the loss of connectivity to the station at 14:56 UT, 14:59 UT, and 15:31 UT. Later in the support, the turbo decoder lost lock for seven seconds at 16:37 UT. This resulted in the loss of about two minutes of instrument SSR data. A DR has been requested. * On day 275 (Oct 2), during the DSS 55 support for Behind, monitor data was lost for 59 minutes beginning at 18:06 UT. All SSR data were recovered. See DR# N106585 for more information. * On day 275 (Oct 2), during the DSS 15 support for Behind, the antenna brakes were set upon the loss of commercial power at the Goldstone complex at 23:50 UT. The station was switched to generator power and tracking services were re-established at 01:14 UT. This resulted in the loss of approximately two hours of instrument SSR data. See DR# G110583 for more information. Week 40 * The Ahead pass on station 34 started about 12 minutes late yesterday (Oct 4) due to a procedural error. This is not believed to have an effect on the SSR downlink. * Station 25 continues to be red. This resulted in a missed pass for Behind last night (Oct 4). Pointers were moved back during a subsequent pass on station 54. This may result in no loss of data, because there are several passes to take up the slack. * A scheduled pass on station 25 for Ahead this morning (Oct 5) was switched to station 15. However, only 2 out of the planned 5 hours were covered. There was a 70 meter track just before, and another track soon afterward, so no data may be lost. * Ahead is scheduled to use station 25 tomorrow. Station 25 is anticipated to be back online at 7 P.M. this evening, so there should not be a problem. * Turbo decoder lock was lost for a few seconds at 15:16 UT during a Behind pass yesterday (Oct 4). * There will be a return-to-service track for station 14 on Ahead on Oct. 8. This will overlap with a station 25 track. The MOC will be able to see the telemetry during the pass, but will otherwise will not use the pass. Although station 14 is a 70 meter station, the track will not be carried out at 720 kbps. * There will be a SECCHI aphelion stepped calibration on Behind on Oct 8, starting at 11:15 UT. The system momentum should be about 2 N-m-s. * Ahead has 720 kbps tracks on Tuesday 278 and Thursday 280. Overall, there are 14 tracks for Ahead during the week. * There are no 720 kbps tracks for Behind during the week. Overall, there are 12 tracks for Behind during the week. * The soft command loss timer will be disabled on Friday, Oct 8, in preparation for the work being done on the restricted IONet in the following week. * The internet will be shut down for 10 minutes on Wednesday, Oct 6, starting at 23:30 UT. The instrument teams will lose connectivity during this time. There are no tracks during this period. Week 41 * Week 41 APL will reconfigure the restricted IONet, moving it to a new MOC in preparation for RBSP. Times blocked out for this activity are 12:00-21:00 UT Monday-Thursday, but it may not take that long. This may lead to problems during Ahead tracks on Oct. 11, 13, and 14. The last two hours of the track are affected on Oct 11 and 14, while the 70 meter track on Oct 13 is during the scheduled downtime. Soft command loss timers will be disabled on both spacecraft for several days. The MOC is looking into if it is possible to send up prerecorded commands stored at the DSN. The 70 meter track will be carried out at 720 kbps, but commanding may not be available. * Commands will be sent up early during the Ahead pass on Oct 11, before the IONet goes down at 12:00 UT. Time tagged commands will also be loaded to free space on both spacecraft for Tuesday, Wednesday, and Thursday. * The 33rd momentum dump will be carried out on Ahead on Friday, Oct. 15, starting at 14:00 UT. * There will be a 720 kbps pass for Ahead on Wednesday, Oct 13. Overall, there are 13 tracks for Ahead, and the coverage is 6.0 hours over nominal. * Aphelion for Behind is Oct 16. * There will be no 720 kbps tracks for Behind this week and 10 tracks overall. Coverage is 1 hour over nominal. * Days 288-289 (Oct 15-16) there will be a 32 hour gap in coverage for Behind but we should be able to ride over it. Week 42 * The soft command loss timer will be re-enabled on Monday, Oct 18. * There will be a 720 kbps track for Ahead on Friday, Oct 22. There will be 12 tracks overall, and coverage is 3.75 hours over nominal. * There will be no 720 kbps tracks for Behind this week. There will be 14 tracks overall, and coverage is 1.75 hours over nominal. Week 43 * Oct 26 is the fourth anniversary of the launch of STEREO. * The 27th momentum dump will be carried out on Behind on Thursday Oct. 28, starting at 17:30 UT. * There will be a 720 kbps track for Ahead on Wednesday, Oct 27. There will be 14 tracks overall, and coverage will be 2.5 hours over nominal. * There will be 720 kbps tracks for Behind on Monday and Tuesday, Oct 25-26. There will be 12 tracks for Behind overall, and coverage will be 1.6 hours over nominal. Week 44 * Daily savings time ends Nov 7. * Ahead will have 720 kbps tracks on Wednesday, Nov 3, and Saturday, Nov 6. There are 14 passes overall, and coverage is 1.25 hours over nominal. * Behind will have a 720 kbps pass on Saturday, Nov 6. There are 14 passes overall, and coverage is 4.3 hours over nominal. Other * SECCHI has been testing a suggested fix for an erratum on one of the chips used in their electronics. It's believed that this will fix the problem with their watchdog resets. The workaround is to poke the value 0 into a bit in the memory register. This will be done in RAM. This fix has been tested on the EDM. They would like to make the change on Ahead first, and monitor it for two weeks before making the change on Behind. A question was raised about the current value in this register. This has been recorded on every SECCHI reboot. Project management agrees with the change. It was decided to schedule the change for after the IONet upgrades. * There was some discussion about the bias in the ranging values from station 24. COORDINATED OBSERVATIONS ------------------------ ------------------------------------------------------------------------------- Scheduled activities for Week 40: M Oct 04 (277) T Oct 05 (278) Ahead: 720 kbps downlink on station 63 Ahead: Change beacon modulation index, 16:15 UT W Oct 06 (279) T Oct 07 (280) Ahead: 720 kbps downlink on station 63 F Oct 08 (281) Ahead: Return-to-service track on station 14 Behind: SECCHI stepped calibration roll, 11:15 UT Both: Disable soft command loss timer S Oct 09 (282) S Oct 10 (283) ------------------------------------------------------------------------------- Scheduled activities for Week 41: M Oct 11 (284) IONet down 12-21 UT T Oct 12 (285) IONet possibly down 12-21 UT W Oct 13 (286) IONet possibly down 12-21 UT, Ahead: 720 kbps downlink on station 43 T Oct 14 (287) IONet possibly down 12-21 UT F Oct 15 (288) Ahead: Momentum dump, 14:00 UT S Oct 16 (289) Behind: Aphelion S Oct 17 (290) ------------------------------------------------------------------------------- Scheduled activities for Week 42: M Oct 18 (291) Both: Re-enable soft command loss timer T Oct 19 (292) W Oct 20 (293) T Oct 21 (294) F Oct 22 (295) Ahead: 720 kbps downlink on station 63 S Oct 23 (296) S Oct 24 (297) ------------------------------------------------------------------------------- Scheduled activities for Week 43: M Oct 25 (298) Behind: 720 kbps downlink on station 43 T Oct 26 (299) Behind: 720 kbps downlink on station 43 Fourth anniversary of STEREO's launch W Oct 27 (300) Ahead: 720 kbps downlink on station 63 T Oct 28 (301) Behind: Momentum dump, 17:30 UT F Oct 29 (302) S Oct 30 (303) S Oct 31 (304) ------------------------------------------------------------------------------- Scheduled activities for Week 44: M Nov 01 (305) T Nov 02 (306) W Nov 03 (307) Ahead: 720 kbps downlink on station 14 T Nov 04 (308) F Nov 05 (309) S Nov 06 (310) Ahead: 720 kbps downlink on station 14 Behind: 720 kbps downlink on station 43 S Nov 07 (311) Daily savings time ends in U.S. ------------------------------------------------------------------------------- Upcoming events: 2010: SECCHI Stepped calibration rolls Ahead: Nov 2 2011: * Jan 12 Both: HGA calibration * Feb 6 STEREO spacecraft at 180 degree separation * 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 * Mar 18 Messenger - Mercury orbital insertion * 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