STEREO Weekly Meeting Minutes for 2008-12-23 (Week 52) ANNOUNCEMENTS ------------- * None INSTRUMENT AND SPACECRAFT STATUS -------------------------------- * All subsystems on both spacecraft are nominal, except that the Ahead spacecraft is currently operating on IMU #2. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 51 * The station 15 transmitter went off-line at 11:25 UT on day 353 (Dec 18) during the Ahead track. Commanding and tracking data were unavailable. This resulted in the loss of 9 minutes of SECCHI data. * Ranging equipment went offline at station 55 at 06:31 during the Ahead track on day 356 (Dec 21), and needed to be reset. This resulted in the loss of 15 minutes of ranging data. * The 18th momentum dump on Ahead was carried out on day 352 (Dec 17) at 13:00 UT. A delta-V of 0.0715 m/s was imparted. * Telemetry lock was intermittent during the station 26 pass on Behind on day 353 (Dec 18) due to heavy snow at Goldstone. Conscan was enabled, and the link was reacquired at 03:43 UT. This resulted in a number of data gaps for 1-2 minutes between the end of Dec 17 and the beginning of Dec 18. * The average daily SSR playback was 7.3 gigabits on Ahead, and 7.2 gigabits on Behind. * The midpoint stepped calibration roll on Behind occurred on day 351 (Dec 16) at 03:50 UT. The SECCHI team reports that the last several calibration rolls have all gone well, and that the script changes were successful. Week 52 * Transmitter problems on station 15 continue, and affected the Ahead pass yesterday (Dec 22). Late on Friday, an additional pass yesterday on station 25 was added so that the partititions could be reset. Several minutes of SSR data was lost during the the sweep. * The STEREO mission will be making frequent use of station 15 over the next couple of weeks. DSN reports that a workaround to allow commanding has been developed, and will give a heads-up to the station to make sure it's used for the upcoming STEREO passes. The problem is expected to be fixed by day 366 (Dec 31). * Heavy rain at station 45 caused problems with intermittent telemetry today (Dec 23) starting at 08:52. In addition, the station switched from generator to commercial power at 09:47, causing the antenna to stop tracking for 28 minutes. * A quiet week is scheduled because of the Christmas holiday on Thursday. APL will be closed for the holidays on both Thursday and Friday, so the instrument teams should arrange to send any necessary commands up before then. Week 01 * A leap second will be added to the spacecraft at the end of day 366 (Dec 31). The instrument teams will see this as a repeat of the second 23:59:59 UT. There will be no tracks during the year rollover. The STEREO software in SolarSoft has been prepared for the upcoming leap second. * APL will be closed for the holidays on both January 1 and 2, so the instrument teams should arrange to send any necessary commands up before then. Week 02 * HGA calibrations are scheduled for both spacecraft on Jan 7, at 15:30 for Ahead and 18:00 for Behind. This calibration will take 1 to 1.5 hours. The spacecraft will roll by +/- 1 degree during the calibration, in 1/2 degree steps. Longer tracks of 7 hour duration are scheduled so that the SSR telemetry can be recovered. Other * January 22 will mark the start of the extended mission. * The MOC will be transitioning to the CCSDS Space Link Telemetry Service over the next few months. This will not affect the instrument teams. * A planned network outage at APL for January has not yet been scheduled. * SWAVES reports that Ahead apparently entered another dust cloud at 12:27 UT on day 352 (Dec 17). The effect is quite strong in the SWAVES data, and has been seen continuously since then. This matches an effect seen at the same longitude two years ago, and possibly last year. SWAVES now thinks that the dust particles are a factor of 100-1000 times smaller than originally thought, and are hitting at solar wind velocity rather than the spacecraft velocity. There's an open question of what is the source of these particles. * IMPACT plans to perform some SWEA testing during the first half of January. They will raise the heater settings to explore some possible temperature dependence in the SWEA efficiency. This testing will occur on both spacecraft. The testing is expected to take 10 days to complete, with about 48 hours between each temperature adjustment. * In looking back over their data, the IMPACT team realizes that the SWEA instruments did not show this problem when the boom was first deployed. Instead the problem gradually developed between Nov 1 and Nov 4, 2006 on both spacecraft, and remains to this day. The problem is manifested as an anomalous peak in counts at 30 eV. They ask whether any spacecraft or instrument activities between Nov 1 to Nov 4, 2006 could be related to this problem. * An EIT shutterless campaign is scheduled for January 16. No special SECCHI observations are planned for this JOP. * The Herschel sounding rocket is scheduled for launch January 23. Their plans mention the use of SECCHI data. Simon Plunkett will look into the question of whether any special observations are requested. COORDINATED OBSERVATIONS ------------------------ ------------------------------------------------------------------------------- Scheduled activities for Week 52: M Dec 22 (357) T Dec 23 (358) W Dec 24 (359) T Dec 25 (360) F Dec 26 (361) S Dec 27 (362) S Dec 28 (363) ------------------------------------------------------------------------------- Scheduled activities for Week 01: M Dec 29 (364) T Dec 30 (365) W Dec 31 (366) Leap second added at end of day T Jan 01 (001) F Jan 02 (002) S Jan 03 (003) S Jan 04 (004) ------------------------------------------------------------------------------- Scheduled activities for Week 02: M Jan 05 (005) T Jan 06 (006) W Jan 07 (007) HGA calibration, Ahead: 15:30 UT, Behind: 18:00 UT T Jan 08 (008) F Jan 09 (009) S Jan 10 (010) S Jan 11 (011) ------------------------------------------------------------------------------- Upcoming events: 2009: ICAL-001: Jan 5-9, Jan 26-30, Mar 2-6, Apr 6-10, May 11-22, Jun 15-19 SECCHI Stepped calibration rolls Ahead: Mar 10, Jun 9, Sep 2, Nov 24 Behind: Mar 10, Jun 16, Sep 22, Dec 22 * Jan TBD Planned network outage at APL * Jan 16 JOP 80, EIT shutterless * Jan 22 Start of extended mission * Jan 23 ICAL14, Herschel sounding rocket launch * Feb 17 DAWN - Mars fly-by * Mar 27, Apr 2 JOP 80, EIT shutterless * Apr 15-29 SUMER campaign (TBC), JOPS 210,211,212,214 * Apr 16 SUMI sounding rocket launch * May 18 Ahead: Switch downlink rate to 360 kbps * Jun 1-Jul 10 Sunrise 5-day balloon flight http://star.mpae.gwdg.de/Sunrise/project/publicat/SPIE_2004.pdf * Jun 8 Behind: Switch downlink rate to 360 kbps * Jul 22 Total solar eclipse http://eclipse.gsfc.nasa.gov/SEmono/TSE2009/TSE2009.html * Aug 4 Both: Increase track duration from 4 to 5 hours * Aug 10 Ahead: Switch downlink rate to 240 kbps * Aug 31 Behind: Switch downlink rate to 240 kbps * Sep 10 Ahead at L4 Lagrange point * Sep 29 Messenger - Mercury fly-by * Oct 25 Behind at L5 Lagrange point * Nov 1-Dec 15 SUMER campaign (TBC) * Dec Behind: Switch downlink rate to 160 kbps