STEREO Weekly Meeting Minutes for 2008-07-29 (Week 31) ANNOUNCEMENTS ------------- * The switch to 480 kbps has been delayed to October 13 for Ahead, and September 15 for Behind based on an updated analysis. INSTRUMENT AND SPACECRAFT STATUS -------------------------------- * All subsystems on both spacecraft are nominal, except that the Ahead spececraft is currently operating on IMU #2. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 30 * On day 204 (Jul 22), no realtime telemetry or commanding was available for the duration of the Ahead track on station 43. The problem was tracked to network changes, and continued the next day on the station 26 Ahead track until it was resolved at 14:06 on day 205 (Jul 23), when the original network configuration was restored. Behind experienced the same problems on the station 45 track on day 205 (Jul 23) which were cleared up at 12:45. All playback data was received on each track. * On day 207 (Jul 25), during the station 54 pass for Behind, no ranging data was obtained because of a recorder anomaly. * The average SSR daily downlink was 7.4 gigabits on Ahead, and 7.7 gigabits on Behind. Week 31 * Yesterday (Jul 28), the transmitter went offline during the station 45 pass on Behind. This resulted in 185 minutes with no ranging or commanding. Because of this problem, the subsequent pass on Ahead was switched to station 43, which is a 70 meter station. * A power supply failure late at station 24 resulted in loss of commanding and realtime telemetry late last night and early this morning (Jul 29). A small amount of data was lost when the uplink frequency was swept to reestablish the link. * There will be a test of the 480 kbps telemetry rate on Ahead on Thursday, Jul 31. This test will be primarily for the MOps and DSN. This rate has been used on the spacecraft in the past. The track will be 5 hours in duration, and will be 24 hours after the preceeding track. The telemetry will be in Turbo 1/4 and NRZ-L format. * There will be another track on Ahead on Jul 31, 3 hours after the previous track. This track will be at 720 kbps, and will include a the 15th momentum dump at 20:20 UT. * The SECCHI team plans to have a large amount of data in their synoptic partition at the beginning of the 480 kbps test track, and anticipate that the partition will still be 20% full at the end of the track. The remainder of the synoptic partition will be read during the following track on the same day, so that partition space will be available for the solar eclipse support observations the following day. * There will be a total solar eclipse at Earth on Friday, Aug 1. SECCHI will support the eclipse observations by moving their high cadence observations to 8-12 UT, which includes the eclipse times at Earth. The first track after the eclipse will be on Ahead at 11:30 UT. Information about total solar eclipse is available at http://eclipse.gsfc.nasa.gov/SEmono/TSE2008/TSE2008.html Week 32 * Five hour tracks will begin August 4 on both spacecraft. However, the actual change to 480 kbps has been pushed back to October 13 for Ahead, and September 15 for Behind. This is based partially on using a link margin of 1.5 dB instead of the previous 3 dB margin. The dates have also been shifted slightly to start the new rate on a Monday in each case. Week 33 * No unusual activities planned. Week 34 * No unusual activities planned. Week 35 * Behind will reach aphelion on day 241 (Aug 28). The SECCHI aphelion stepped calibration roll is scheduled on Behind on day 239 (Aug 26) at 20:15 UT. This roll will be done with the updated procedures used the last time. Other * Once the switch to 480 kbps takes place, there will be ocassional tracks using 70 meter dishes, when 720 kbps can be supported. There is additional SECCHI telemetry which can be brought down during these tracks. Also, the in-situ instruments will get double playback. COORDINATED OBSERVATIONS ------------------------ ------------------------------------------------------------------------------- Scheduled activities for Week 31: M Jul 28 (210) T Jul 29 (211) W Jul 30 (212) JOP 80, EIT shutterless, 17:00-19:50 UT T Jul 31 (213) Ahead: 480 kbps test track Ahead: momentum dump, 20:20 UT F Aug 01 (214) Total solar eclipse, 9:20-11:20 UT S Aug 02 (215) S Aug 03 (216) Notes: * Information about total solar eclipse available at http://eclipse.gsfc.nasa.gov/SEmono/TSE2008/TSE2008.html * STEREO plans available at http://stereo-ssc.nascom.nasa.gov/plans/eclipse.shtml ------------------------------------------------------------------------------- Scheduled activities for Week 32: M Aug 04 (217) Both: Begin 5 hour daily DSN tracks T Aug 05 (218) W Aug 06 (219) T Aug 07 (220) F Aug 08 (221) S Aug 09 (222) S Aug 10 (223) ------------------------------------------------------------------------------- Scheduled activities for Week 33: M Aug 11 (224) T Aug 12 (225) W Aug 13 (226) T Aug 14 (227) F Aug 15 (228) S Aug 16 (229) S Aug 17 (230) ------------------------------------------------------------------------------- Scheduled activities for Week 34: M Aug 18 (231) T Aug 19 (232) W Aug 20 (233) T Aug 21 (234) F Aug 22 (235) S Aug 23 (236) S Aug 24 (237) ------------------------------------------------------------------------------- Scheduled activities for Week 35: M Aug 25 (238) T Aug 26 (239) Behind: SECCHI stepped calibration roll 20:15 UT W Aug 27 (240) T Aug 28 (241) F Aug 29 (242) S Aug 30 (243) S Aug 31 (244) ------------------------------------------------------------------------------- Upcoming events: 2008: SECCHI Stepped calibration rolls Ahead: Sep 23, Dec 16 Behind: Aug 26, Dec 2 ICAL-001: Aug 4-8, Sep 1-5, Oct 6-10, Nov 3-7, Dec 1-5 * Sep 15 Behind: Switch downlink rate to 480 kbps * Oct 6 Messenger - Mercury fly-by * Oct 13 Ahead: Switch downlink rate to 480 kbps * Oct 16,28 JOP 80, EIT shutterless * Nov 1-Dec 15 SUMER campaign (may be cancelled)