STEREO Weekly Meeting Minutes for 2010-05-11 (Week 19) ANNOUNCEMENTS ------------- * Commercial power will be out at APL during Memorial Day weekend from Friday (May 28) to Monday (May 31). The MOC will be operating on UPS and a generator. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * All subsystems on both spacecraft are nominal. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 18 * The station 26 transmitter was red at the beginning of the pass for Ahead on day 125 (May 5) due to the generator overloading. This resulted in the lof of 181 minutes of command and tracking data, and several minutes of SSR data. * DSN stations switched to using 10 kW for uplink power on both spacecraft starting on day 127 (May 7). * SECCHI/HI calibration offpoints were carried out on day 126 (May 6), at 09:35 UT on Ahead, and 17:50 UT on Behind. The maximum offset was about 1.25 degrees about the spacecraft Y axis, and the activity lasted about 90 minutes. * The insitu SSR partitions on Behind reached capacity on day 122 and 123 (May 2-3) due to insufficient telemetry coverage during the previous week consisting of a 31 hour gap over day 120 (Apr 30), followed by two short tracks on days 121 and 122 (May 1-2). * Telemetry lock was lost during the station 45 pass for Behind on day 124 (May.4) between 06:41 and 06:48 UT, due to heavy rain. This resulted in the loss of several minutes of SSR data. * Uplink was lost starting at 23:02 UT during the station 26 pass for Behind on day 127 (May 7), and continuing through 03:04 UT the next day. This resulted in the loss of 242 minutes of command and tracking data, and several minutes of SSR data when the uplink was reswept. In addition, since the planned write limit pointer resets did not occur, this resulted in the loss of several hours of SSR data for the insitu instruments. * An autonomy rule has been prepared to automatically move pointers during a pass when the partitions are close to full. This new rule requires CCB approval. The rule would act only during a pass, and would catch up the write limit pointer with the read pointer. * The average daily SSR downlink during the week was 4.8 gigabits for Ahead, and 4.5 gigabits for Behind. * SECCHI asked whether there were any reports available about the HI calibration maneuvers outside of the attitude history files. The command history files should show the pointing timings. Week 19 * 70 meter support for both spacecraft on Monday, May 10, allowed the recorders to be emptied. * There is a 4.3 hour track on Ahead tomorrow (May 12) * There is an 8 hour track on Behind today (May 11). * Overall, both spacecraft should be okay for track time during the week. Week 20 * Events on other missions are affecting the STEREO DSN schedule during the week. The Japanese JAXA mission Akatsuki (PLANET-C, previously known as Venus Climate Orbiter) is scheduled for launch on Monday, May 17, at 21:44 UT. Because of this, there are several long gaps between passes for both spacecraft during the week. * Ahead will be at perihelion on May 18 at 18:57 UT. The 13th SECCHI stepped calibration roll is scheduled for 00:25 on that day. The system momentum is expected to be ~2 N-m-s. * Ahead has a 34 hour gap between passes Tuesday to Thursday (May 18-20). * Pointers will be moved during the week to avoid losing data. * There will be a 70 meter downlink on station 43 for the Ahead spacecraft on May 23. This will be carried out at 720 kbps. Because the pass duration is just 2 hours, only science data will be downlinked. * There is a 2.7 hour pass for Behind on station 34 on Friday, May 21. Because of the short duration, no spacecraft data will be downlinked, only science data. * Some attitude history data may be lost for Behind, but not for Ahead. * Behind has long gaps between passes Monday-Tuesday, and again Wednesday-Thursday. Passes on Saturday and Sunday are five hours long. Week 21 * Behind in-situ partions are expected to be close to 100% all week. There are a lot of short tracks. There is a lot of contention for DSN services for the part of the sky containing Behind. * Track coverage for Ahead should be okay, but Behind is short by 7.4 hours. * A short track was added for Ahead on Friday (May 28), alleviating a previous 31 hour gap. * Commercial power will be out at APL during Memorial Day weekend starting at 6 P.M. on Friday (May 28) to Monday (May 31). The MOC will be operating on UPS and a generator. Phones and email should be working. There should be no impact to the STEREO project. Other * PLASTIC requested realtime commanding for Ahead. It was decided to do this tomorrow (May 12) staring around 8 A.M. * SECCHI asked about rescheduling the GT calibration activity for Ahead. This did not occur because SECCHI had a watchdog reset. It has been rescheduled for Wednesday, May 26th, starting at 9:25 UT. This activity involves SECCHI making slight adjustments in the spacecraft pointing by manipulating the GT offset, and lasts 90 minutes. COORDINATED OBSERVATIONS ------------------------ ------------------------------------------------------------------------------- Scheduled activities for Week 19: M May 10 (130) Both: 720 kbps downlink T May 11 (131) W May 12 (132) T May 13 (133) F May 14 (134) S May 15 (135) S May 16 (136) ------------------------------------------------------------------------------- Scheduled activities for Week 20: M May 17 (137) T May 18 (138) Ahead: SECCHI stepped calibration roll, 00:25 UT Ahead: Perihelion, 18:57 UT Behind: 31 hour gap between passes W May 19 (139) T May 20 (140) Ahead: 34 hour gap between passes F May 21 (141) Behind: 35.5 hour gap between passes S May 22 (142) S May 23 (143) Ahead: 720 kbps downlink on station 43 ------------------------------------------------------------------------------- Scheduled activities for Week 21: M May 24 (144) T May 25 (145) W May 26 (146) Ahead: SECCHI GT calibration offset, 9:25 UT T May 27 (147) F May 28 (148) S May 29 (149) S May 30 (150) Notes: * Commercial power will off at APL during Memorial Day weekend, May 28-31. The STEREO MOC will be operating on UPS and a generator. ------------------------------------------------------------------------------- Upcoming events: 2010: SECCHI Stepped calibration rolls Ahead: Aug 10, Nov 2 Behind: Jul 13, Oct 12 * Jun 8 SUMI sounding rocket launch http://adsabs.harvard.edu/abs/2008AGUSMSP51B..01A * Jul 8,15 EIT shutterless (TBC) * Jul 11 Total solar eclipse http://eclipse.gsfc.nasa.gov/SEmono/TSE2010/TSE2010.html * Jul 14 Both: HGA calibration * Aug 23 Ahead: End use of 720 kbps on 70 m DSN subnet * Sep 6 Behind: End use of 720 kbps on 70 m DSN subnet * Sep 7 Both: Begin 8 hour daily DSN tracks * Sep 13 Both: Switch downlink rate to 160 kbps * Nov 15 Behind: Switch downlink rate to 120 kbps 2011: * Jan 12 Both: HGA calibration * Feb 6 STEREO spacecraft at 180 degree separation * Mar 18 Messenger - Mercury orbital insertion * Apr 11 Ahead: Switch downlink rate to 120 kbps * Jul DAWN - Vesta arrival * Jul 13 Both: HGA calibration * Sep 19 Behind: Switch downlink rate to 96 kbps * Sep 26 Ahead: Switch downlink rate to 96 kbps 2012: * Jan 9 Behind: End use of 480 kbps on 70 m DSN subnet * Jan 11 Both: HGA calibration * Jun 25 Ahead: End use of 480 kbps on 70 m DSN subnet * Jul DAWN - Vesta departure * Jul 11 Both: HGA calibration * Aug 20 Both: Switch downlink rate to 30 kbps * Nov 13 Total solar eclipse, south Pacific 2013: * Nov 25 Behind: End use of 360 kbps on 70 m DSN subnet * Dec 12 Ahead: Mercury transit 2014: * Apr 29 Behind: Mercury transit 2015: * Feb DAWN - Ceres arrival * Jan 10 - Apr 12 Behind: Spacecraft behind Sun * Feb 17 - Aug 2 Ahead: Spacecraft behind Sun * May 25 Ahead: End use of 360 kbps on 70 m DSN subnet * Aug 10 Ahead: Begin use of 360 kbps on 70 m DSN subnet * Jul 23 - Nov 10 Behind: Spacecraft behind Sun * Jul DAWN - End of nominal mission 2016: 2017: 2018: * Mar 5 Ahead: Mercury transit