STEREO Weekly Meeting Minutes for 2009-02-10 (Week 07) 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 05 * Telemetry lock was intermittent for both spacecraft using station 54 on days 28 and 29 (Jan 28, 29). This problem was cleared by switching from channel 5 to channel 1 at the station. * The uplink for Ahead was established 8 minutes late on day 31 (Jan 31) on station 45. This resulted in the loss of some SECCHI data. * PLASTIC commanded their MCP voltages on Ahead on day 27 (Jan 27) and Behind on day 28 (Jan 28). * Telemetry lock was intermittent during part of the Behind pass on day 28 (Jan 28), from 2:16-2:58 UT. This resulted in some SSR loss for all instruments. * The average daily downlink was 6.3 gigabits on Ahead, and 7.3 gigabits on Behind. Week 06 * The 19th momentum dump was performed on Ahead on February 4, with ignition at 14:00 UT. A delta-V of 0.0741 m/s was imparted. * Telemetry lock was lost briefly on Behind during the station 65 track on day 35 (Feb 4). A small amount of SECCHI data was lost. * The average daily downlink was 6.2 gigabits on Ahead, and 7.0 gigabits on Behind. Week 07 * An unnumbered JOP (High Cadence Study of Quiet Sun Supergranular EUV Brightenings) is scheduled for Feb 12-15, with SECCHI participation. Week 08 * A previously unscheduled SECCHI stepped calibration roll on Behind is scheduled for day 48 (Feb 17). The system momentum during this roll will be low, around 1 m/s. This roll was requested by the SECCHI team because of a sudden change in the COR1-B scattered light profile, probably due to a piece of dust landing on the objective lens. Previously, COR1-B had considerably less scattered light than COR1-A. Now they have comparable scattered light levels. Behind will be at perihelion on day 70 (March 11). The calibration roll that would normally be scheduled around that time is now scheduled for day 97 (Apr 7), to move the rolls farther apart. * DAWN will fly by Mars on Feb 17. Week 09 * No significant activities planned. Week 10 * No significant activities planned. Other * APL plans to increase the frequency of momentum dumps on Behind to be similar to that currently used for Ahead. This should remove a 1 arc second spike seen in wheel #2, presumably due to friction. Keeping the momentum lower should avoid this spike. The next momentum dump on Behind is projected to occur on day 70 (Mar 11). * At the last telecon, the SECCHI team raised the question of resetting SSR pointers midway into the pass. APL has studied the problem, and distributed a memo describing the possible effects. NRL is also continuing to study the issue, and now thinks that the plan may only give a marginal improvement during the extended mission. * The SECCHI HI team has requested to roll each spacecraft by 180 degrees for 6 hours to examine the L4 and L5 points as the spacecraft approaches them. They would like to perform this maneuver once a month. These maneuvers do not need to be simultaneous, and it may be better from a science standpoint to do them at separate times. Depending on the results of these measurements, they may request that the maneuvers be more frequent as the spacecraft approach the Lagrange points. APL points out that these roll maneuvers require that the system momentum be low. * Some questions were raised about the review process for the planned reboot process. There will be a design review board for both the code changes, and for the scripts that will implement the changes. APL plans to go through their internal reviews first, and then meet with the instrument teams and Goddard project management to go over the plan. Goddard project management will have the final say on whether or not the changes are made. The benefits of the planned G&C changes is that it will make it easier to blend rates from any of the IMU, ST, and GT to make the system more robust in case of component failure. * SWAVES asked about the leap-year problem that affected the GRT values in the telemetry files for Dec 31, 2008. This problem should be fixed in the .fin files. COORDINATED OBSERVATIONS ------------------------ ------------------------------------------------------------------------------- Scheduled activities for Week 07: M Feb 09 (040) T Feb 10 (041) W Feb 11 (042) T Feb 12 (043) F Feb 13 (044) S Feb 14 (045) S Feb 15 (046) Notes: * Feb 12-15 JOP x: High Cadence Study of Quiet Sun Supergranular EUV Brightenings ------------------------------------------------------------------------------- Scheduled activities for Week 08: M Feb 16 (047) T Feb 17 (048) Behind: SECCHI stepped calibration roll, 13:00 DAWN - Mars fly-by W Feb 18 (049) T Feb 19 (050) F Feb 20 (051) S Feb 21 (052) S Feb 22 (053) ------------------------------------------------------------------------------- Scheduled activities for Week 09: M Feb 23 (054) T Feb 24 (055) W Feb 25 (056) T Feb 26 (057) F Feb 27 (058) S Feb 28 (059) S Mar 01 (060) ------------------------------------------------------------------------------- Scheduled activities for Week 10: M Mar 02 (061) T Mar 03 (062) W Mar 04 (063) T Mar 05 (064) F Mar 06 (065) S Mar 07 (066) S Mar 08 (067) ------------------------------------------------------------------------------- Upcoming events: 2009: ICAL-001: Jan 26-30, Mar 2-6, Apr 6-10, May 11-22, Jun 15-19, Jul 13-17 SECCHI Stepped calibration rolls Ahead: Mar 10, Jun 9, Sep 2, Nov 24 Behind: Apr 7, Jun 16, Sep 22, Dec 22 * Mar 9 (TBC) ICAL14, Herschel sounding rocket launch http://sohowww.nascom.nasa.gov/soc/JOPs/ical014-draft.pdf * 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 http://adsabs.harvard.edu/abs/2008AGUSMSP51B..01A * May 11 Both: Begin 6 hour daily DSN tracks * 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 1 Both: HGA calibration * Jul 22 Total solar eclipse http://eclipse.gsfc.nasa.gov/SEmono/TSE2009/TSE2009.html * Aug 3 Both: Begin 7 hour daily DSN tracks * 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 26 Behind at L5 Lagrange point * Nov 1-Dec 15 SUMER campaign (TBC) * Dec 7 Behind: Begin 8 hour daily DSN tracks * Dec 14 Behind: Switch downlink rate to 160 kbps 2010: SECCHI Stepped calibration rolls Ahead: Feb 23, May 18, Aug 10, Nov 2 Behind: Apr 6, Jul 13, Oct 12 * Jan 6 Both: HGA calibration * Apr 19 Ahead: Begin 8 hour daily DSN tracks * Apr 26 Ahead: Switch downlink rate to 160 kbps * Jul 11 Total solar eclipse http://eclipse.gsfc.nasa.gov/SEmono/TSE2010/TSE2010.html * Jul 14 Both: HGA calibration * Nov 15 Behind: Switch downlink rate to 120 kbps 2011: * Jan 12 Both: HGA calibration * Mar 18 Messenger - Mercury orbital insertion * Apr 11 Ahead: Switch downlink rate to 120 kbps * Jul 13 Both: HGA calibration * Aug DAWN - Vesta arrival * Sep 19 Behind: Switch downlink rate to 96 kbps * Sep 26 Ahead: Switch downlink rate to 96 kbps 2012: * Jan 11 Both: HGA calibration * May DAWN - Vesta departure * Jul 11 Both: HGA calibration * Aug Both: Switch downlink rate to 30 kbps 2013: 2014: 2015: * Feb DAWN - Ceres arrival * Jan 10 - Apr 12 Behind: Spacecraft behind Sun * Feb 17 - Aug 2 Ahead: Spacecraft behind Sun * Jul 23 - Nov 10 Behind: Spacecraft behind Sun * Jul DAWN - End of nominal mission