STEREO Weekly Meeting Minutes for 2008-07-01 (Week 27) ANNOUNCEMENTS ------------- * None. 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 26 * SECCHI stepped calibration rolls were carried out on both spacecraft, on day 178 (Jun 26) for Ahead, and day 177 (Jun 25) for Behind. The G&C data showed that pointing was maintained throughout the roll. This was confirmed by the SECCHI COR1 images. For Ahead, this was the perihelion maneuver, while for Behind it was a makeup for an earlier roll that had problems. * The average daily downlink was 7.4 gigabits for Ahead, and 7.6 gigabits for Behind. Week 27 * SECCHI GT-driven off-points were carried out yesterday (Jun 30) on both spacecraft. These off-points are used to flat field the EUVI telescope. * The station 25 transmitter tripped off at 12:42 UT during the Ahead track yesterday, in the middle of the track. When the transmitter was recovered, it was decided to not resweep the uplink to avoid disrupting the data playback. Week 28 * The second of the SECCHI GT-driven off-points for EUVI calibration will occur on both spacecraft on Monday, Jul 7, at 16:15 UT. This event will be the same as the previous week, except that the other two wavelengths will be covered. * The 8th HGA calibrations are scheduled on both spacecraft on day 191 (Jul 9), at 14:00 UT for Ahead, and 17:00 UT for Behind. HGA roll scripts in case of star tracker loss will also be tested. The tests are split between the spacecraft, and will roll by +/- 0.5 on Ahead, and +/- 1.0 degrees on Behind. The tests are being combined with the HGA calibrations because they use the same DSN configuration. The HGA calibration will take about an hour, and the script testing will take about 45 minutes to an hour. There is sufficient time in the track to perform both of these activities, and to play back the SSR data. Week 29 * The 10th momentum dump will be performed on Behind on day 199 (Jul 17) at 19:45 UT. Week 30 * Nothing unusual planned. Other * Track durations on both spacecraft will increase from 4 to 5 hours on both spacecraft on Aug 4. Ahead is expected to drop to 480 kbps around Aug 11, and Behind around Sep 8. * There was some discussion about using a telemetry rate of 240 kbps. APL reports that this is an untested capability on board the spacecraft, and are discussing how best to implement it. * A report is close to completion on the star tracker anomaly. * Honeywell has issued a report on the IMU failure. * There was some discussion about supplying blanket samples to the SWAVES team for testing, regarding the apparent dust impacts seen on the spacecraft. * FDF reports that they have seen apparent increases in the solar reflectivity factor in the orbit solution for the two spacecraft, particularly for Ahead. It's not clear yet whether this is real, or a modeling issue. * A total solar eclipse will occur on August 1st. COORDINATED OBSERVATIONS ------------------------ ------------------------------------------------------------------------------- Scheduled activities for Week 27: M Jun 30 (182) SECCHI GT-driven off-point, Ahead 16:15, Behind 12:15 T Jul 01 (183) W Jul 02 (184) T Jul 03 (185) F Jul 04 (186) S Jul 05 (187) S Jul 06 (188) Notes: * Jun 20-30, SUMER observing ------------------------------------------------------------------------------- Scheduled activities for Week 28: M Jul 07 (189) Both: SECCHI GT-driven off-point, 16:15 UT T Jul 08 (190) W Jul 09 (191) HGA calibrations, Ahead: 14:00, Behind: 17:00 T Jul 10 (192) F Jul 11 (193) S Jul 12 (194) S Jul 13 (195) ------------------------------------------------------------------------------- Scheduled activities for Week 29: M Jul 14 (196) T Jul 15 (197) W Jul 16 (198) T Jul 17 (199) Behind: momentum dump, 19:45 F Jul 18 (200) S Jul 19 (201) S Jul 20 (202) Notes: * ICAL July 15 or 16 ------------------------------------------------------------------------------- Scheduled activities for Week 30: M Jul 21 (203) T Jul 22 (204) W Jul 23 (205) T Jul 24 (206) F Jul 25 (207) S Jul 26 (208) S Jul 27 (209) ------------------------------------------------------------------------------- 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 * Jul 23,30 EIT shutterless * Aug 1 Total solar eclipse, 9:20-11:20 UT http://eclipse.gsfc.nasa.gov/SEmono/TSE2008/TSE2008.html * Aug 4 Begin 5 hour daily DSN tracks * Aug 11 Ahead: Switch downlink rate to 480 kbps * Sep 8 Behind: Switch downlink rate to 480 kbps * Oct 6 Messenger - Mercury fly-by * Nov 1-Dec 15 SUMER campaign