STEREO Weekly Meeting Minutes for 2011-03-15 (Week 11) ANNOUNCEMENTS ------------- * None. INSTRUMENT and SPACECRAFT STATUS -------------------------------- * All subsystems on both spacecraft are nominal. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 10 * On day 070 (Mar 11), during the DSS 54 support for Ahead, the DCD failed over to the redundant side at 1030z. Currently approximately 45 minutes of instrument SSR data are missing; however, the DSN is attempting to recover it. See DR# M106233 for more information. * On day 067 (Mar 8), the playback of SECCHI SSR2, special event partition #20, was enabled on Ahead at 0637z. To optimize downlink bandwidth, after playing back the recorded data, the playback was disabled at 071-1455z (Mar 12). * On day 067 (Mar 8), the 36th momentum dump on Ahead was successfully executed at 1600Z, which imparted a delta V of 0.0927 m/sec. * On day 068 (Mar 9), during the DSS 26 support for Behind, ranging lock was lost at 0103z. The uplink ranging assembly was reset and ranging lock was reacquired at 0125z. This resulted in the loss of 22 minutes of ranging data. See DR# G111186 for more information. * On day 070 (Mar 11), during the DSS 14 support for Behind, telemetry lock was lost at 0228z. The station initiated a CONSCAN and the downlink signal was reacquired at 0242z. The problem recurred again intermittently from 0308z through 0339z. These anomalies resulted in the loss of two hours of instrument SSR data. See DR# G111191 & G111192 for more information. * On day 066 (Mar 7), the playback of SECCHI SSR2, special event partition #20, was enabled on Behind at 2245z. To optimize downlink bandwidth, after playing back the recorded data, the playback was disabled at 068-1820z (Mar 9). * On day 069 (Mar 10), the 30th momentum dump was successfully executed on Behind at 1945z, which imparted a delta V of 0.0696 m/sec. * The average daily SSR playback volume was 4.7 gigabits for Ahead, and 5.5 gigabits for Behind. * SECCHI/COR1 reports that the telescope background rose in association with the recent momentum dumps on both spacecraft, and asks if there was anything unusual about either of these dumps. The dump on Behind is unusual because the COR1 and COR2 doors failed to open after the dump due to a scheduling problem, and had to be opened by ground command on the following day. This led to a significant increase in the COR1-B temperature. No unusual events are reported for the Ahead momentum dump. SWAVES reports a large number of dust events on Ahead during Mar 9-11, but this is after the momentum dump. Week 11 * The data handling system release 1.1.2 was written to EEPROM on Ahead this morning (Mar 15), and will be written to EEPROM on Behind this afternoon. * The DCD failed over to the redundant side during the station 14 pass for Behind today (Mar 15). This resulted in files being dropped which will need to be recovered. * Ahead has 720 kbps passes on Monday, Mar 14, Thursday, Mar 17 (D43), Friday, Mar 18 (D43), Saturday, Mar 19 (D14), and Sunday, Mar 20 (D14). There are 11 passes during the week, and overall coverage is nominal. * Behind has 720 kbps passes on Monday, Mar 14 (D14), Friday, Mar 18 (D63), and Sunday, Mar 20 (D14). There are 12 passes during the week, and overall coverage is 1.6 hours above nominal. * Messenger will begin orbital insertion around Mercury on Thursday night, Mar 17, starting at 8:45 P.M. EDT. Week 12 * Ahead will have an additional SECCHI stepped calibration roll on Mar 22, starting at 9:15 UT, to assist with the recent changes in the COR1-A background. The system momentum will be around 6 N-m-s. * Ahead has 720 kbps passes on Tuesday, Mar 22, Wednesday, Mar 23, Thursday, Mar 24, and Sunday, Mar 27, all using station 43. There are 14 passes during the week, and overall coverage is nominal. * Behind has 720 kbps passes on Wednesday, Mar 23 (D43 and D63), Thursday, Mar 24 (D63), Friday, Mar 25 (D63), and Sunday, Mar 27 (D43). There are 14 passes during the week, and overall coverage is 2.4 hours above nominal. Week 13 * Ahead has 720 kbps passes on Monday, Mar 28 (D43), Thursday, Mar 31 (D43), and Sunday, Apr 3 (D14). There are 12 passes during the week, and overall coverage is nominal. * Behind has a 720 kbps pass on Tuesday, Mar 29, using station 63. There are 14 passes during the week, and overall coverage is 5.3 hours above nominal. Week 14 * Ahead has 720 kbps passes on Monday, Apr 4 (D43), and Friday, Apr 8 (D14). There are 12 passes during the week, and overall coverage is nominal. * Behind has a 720 kbps pass on Monday, Apr 4, using station 63. There are 13 passes during the week, and overall coverage is 8.2 hours over nominal. Week 15 * 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 13 passes during the week, and overall coverage is 9.4 hours above nominal. Other * Track coverage plans exist through the end of June. * There are continuing problems with the station 14 pointing model which causes it to occasionally lose telemetry lock. This is particularly a problem at low elevations, below 20 degrees. The MESSENGER spacecraft has also been seeing offset differences once it crosses 160 degrees of azimuth. The offset is updated manually every few minutes. Once lock is established, it is maintained with CONSCAN. In addition to the pointing model problems, station 14 has lately been having mechanical problems with the brakes setting occasionally. * Station 15 has been having problems with its transmitter. DSN will confirm whether or not it will be back in service by Monday. * There was some discussion of the conops for SECCHI's SSR2 partition. The MOC plans to routinely force the write pointer to be the lead pointer at the start of every playback, so that it will correctly report 100% when it is full. COORDINATED OBSERVATIONS ------------------------ ------------------------------------------------------------------------------- Scheduled activities for Week 11: M Mar 14 (073) Ahead: 720 kbps downlink (TBC) T Mar 15 (074) W Mar 16 (075) T Mar 17 (076) Ahead: 720 kbps downlink on station 43 F Mar 18 (077) Ahead: 720 kbps downlink on station 43 Messenger - Mercury orbital insertion S Mar 19 (078) Ahead: 720 kbps downlink on station 14 S Mar 20 (079) Ahead: 720 kbps downlink on station 14 ------------------------------------------------------------------------------- Scheduled activities for Week 12: M Mar 21 (080) T Mar 22 (081) Ahead: SECCHI stepped calibration roll, 9:15 UT Ahead: 720 kbps downlink on station 43 W Mar 23 (082) Ahead: 720 kbps downlink on station 43 Behind: 720 kbps downlink on stations 43 and 63 T Mar 24 (083) Ahead: 720 kbps downlink on station 43 Behind: 720 kbps downlink on station 63 F Mar 25 (084) Behind: 720 kbps downlink on station 63 S Mar 26 (085) S Mar 27 (086) Ahead: 720 kbps downlink on station 43 Behind: 720 kbps downlink on station 43 ------------------------------------------------------------------------------- Scheduled activities for Week 13: M Mar 28 (087) Ahead: 720 kbps downlink on station 43 T Mar 29 (088) Behind: 720 kbps downlink on station 63 W Mar 30 (089) T Mar 31 (090) Ahead: 720 kbps downlink on station 43 F Apr 01 (091) S Apr 02 (092) S Apr 03 (093) Ahead: 720 kbps downlink on station 14 ------------------------------------------------------------------------------- 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) W Apr 06 (096) T Apr 07 (097) F Apr 08 (098) Ahead: 720 kbps downlink on station 14 S Apr 09 (099) 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 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 ------------------------------------------------------------------------------- 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