STEREO Weekly Meeting Minutes for 2010-04-20 (Week 16) ANNOUNCEMENTS ------------- * None. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * All subsystems on both spacecraft are nominal. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 15 * Command uplink was delayed by 15 minutes due to a transmitter anomaly during the 4 hour return-to-service track on station 34 for Ahead late Wednesday, day 104 (Apr 14). SSR playback was initiated manually, so this did not affect the SSR downlink. * G&C software version 3.2.6 was loaded to EEPROM copy 1 on Ahead on Thursday, day 105 (Apr 15). * PLASTIC lost SSD-related data, including some SSD housekeeping, on day 105 (Apr 15). They were able to send a reset command from the ground to correct the anomaly. * The in-situ instruments on Behind began overwriting their partitions on day 105 (Apr 15) due to a gap in coverage on day 103 (Apr 13). This resulted in the loss of several hours of SSR in-situ data. * The average daily SSR downlink was 5.6 gigabits for Ahead, and 4.4 gigabits for Behind. Week 16 * Switched to 7 hour DSN tracks for Ahead starting Apr 19. * The new macros for the 240 and 120 kbps telemetry rates were tested on Ahead yesterday (Apr 19). * The 29th momentum dump will be carried out on Ahead on Wednesday, Apr 21, starting at 16:00 UT. * Ahead will have a 70 meter pass on station 43 on Thursday, Apr 22. This will be carried out at 720 kbps, and double playback of insitu data will be disabled. Week 17 * Switch to 240 kbps rate for Ahead starting with the station 26 pass on Apr 26. * The 23rd momentum dump will be carried out on Behind on Tuesday, Apr 27, starting at 20:30 UT. * A SECCHI-driven GT calibration offpoint is planned for Wednesday, Apr 28, starting at 7:30 UT on both spacecraft. The amount of offpoint should be on the order of an arc minute, and the activity lasts about 90 minutes. Week 18 * An SDO/EVE calibration sounding rocket launch is scheduled for Monday, May 3. This affected the Behind schedule due to SOHO support for the launch. More time has been negotiatied for STEREO to mitigate the schedule changes. * SECCHI/HI calibration offpoints are scheduled for Thursday, May 6, at 09:35 UT on Ahead, and 17:50 UT on Behind. The maximum offset is about 1.5 degrees about the spacecraft Y axis, and the activity lasts about 90 minutes. Week 19 * 70 meter support is planned for both spacecraft on Monday, May 10, using Madrid station 63 for Ahead, and Canberra station 43 for Behind. These will be carried out at 720 kbps, and double playback of insitu data will be disabled. 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, the Ahead pass on Thursday, May 20 will follow a 34 hour gap. Pointers will be moved for this and the following tracks until the buffers can be cleared. * Ahead will be at perihelion on May 18. 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. * Additional schedule pressure results from Behind being lined up with Mars, and maneuvers by the Japanese JAXA mission Hayabusa (MUSES-C). There will be two large gaps during the week, a 39 hour gap between Monday and Tuesday, and a 35.5 hour gap between Wednesday and Thursday. The pass on Thursday is only 2.7 hours long. Pointers will be moved for these and the following tracks until the buffers can be cleared. It is expected that the insitu and spacecraft buffers will be overwritten several times during this period. Other * STEREO is now in the extended mission phase, and thus has lower priority. Also, the increasing range of STEREO requires more DSN time. An additional constraint during this period is the SOHO final continuous observing campaign which starts May 4. Some time will be freed up once this campaign is over in early July. SOHO will be using quite a bit less DSN time afterwards. * Next year is also expected to have a very high level of contentions for DSN time, with several launches and orbital insertions occurring. * PLASTIC asked if there were any particle storms occuring at the same time as their anomaly on Ahead on day 105 (Apr 15) at 4:43:57 UT. Their count rate jumped suddenly by several orders of magnitude, and then dropped back down to normal within a minute. This is consistent with a micrometeorite hit within their detector, in the direction which looks away from the Sun. A preliminary look at SECCHI images show no particle storm that day. SWAVES did not see a glitch at that time, but did see one at 5:00 UT. * There was some discussion of the 1553 error that was reported last week. Events have been seen on both spacecraft recently, but were not seen in the early days of the mission, or in the ground testing. There may be a relationship between the errors seen by SWAVES and IMPACT/PLASTIC. More investigation is needed to see if these errors are simultaneous. * SWAVES reports that they've previously seen some 1553 glitches on Ahead. The last one was 29 Jan 2010 in the minute before 01:57:44 UT. * SWAVES saw a 1553 glitch on Behind on 9 Feb 2010 in the minute before 15:20:44 UT, and another on 11 April 2010 in the minute before 06:47:30 UT. There were no 1553 errors seen on Behind previous to these. COORDINATED OBSERVATIONS ------------------------ ------------------------------------------------------------------------------- Scheduled activities for Week 16: M Apr 19 (109) Ahead: Begin 7 hour daily DSN tracks Ahead: Test of 240 and 120 kbps telemetry rates, 17:00 UT T Apr 20 (110) W Apr 21 (111) Ahead: Momentum dump, 16:00 UT T Apr 22 (112) Ahead: 720 kbps downlink on station 43 F Apr 23 (113) S Apr 24 (114) S Apr 25 (115) ------------------------------------------------------------------------------- Scheduled activities for Week 17: M Apr 26 (116) Ahead: Switch downlink rate to 240 kbps T Apr 27 (117) Behind: Momentum dump, 20:30 UT W Apr 28 (118) Both: SECCHI-driven GT calibration offpoint, 7:30 UT T Apr 29 (119) F Apr 30 (120) S May 01 (121) S May 02 (122) ------------------------------------------------------------------------------- Scheduled activities for Week 18: M May 03 (123) EVE calibration sounding rocket launch, 18:12 UT T May 04 (124) EVE calibration sounding rocket launch backup, 18:12 UT W May 05 (125) T May 06 (126) SECCHI HI stray light cal. offpoint, Ahead: 09:35, Behind: 17:50 F May 07 (127) S May 08 (128) S May 09 (129) ------------------------------------------------------------------------------- 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 Behind: 39 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) ------------------------------------------------------------------------------- Upcoming events: 2010: ICAL-001: May 3-7 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