STEREO Weekly Meeting Minutes for 2007-01-03 (Week 01) ANNOUNCEMENTS ------------- INSTRUMENT AND SPACECRAFT STATUS -------------------------------- * All subsystems on both spacecraft are nominal. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 2006-52 * Xmas-day track unattended, but played back recorder * SECCHI-GT calibration on Ahead. * Dropped Ahead rate to 480 kbps. Rate will drop again to 360 kbps, and then back up to 720 kbps on Jan 8. * Some instruments overflowed R/T telemetry queues on several occasions. When this happens the spacecraft starts logging anomalies. Last week had so many overflows that R/T started filling with anomaly packets, and the software started starving out software tasks. The processor came close to system reset. The anomaly reporting has been suppressed for the time being. - PLASTIC periodically bursts up to 6 kbps. PLASTIC has a 5 minute cadence, and uses the available bandwidth to meter this out. The PLASTIC buffer allocation could be changed, but this would require a reboot of the processor. Other options would require an IDPU software change, or a table change to not bring down all the PLASTIC APIDs in R/T. - SECCHI started sending data to R/T that it was not supposed to. The reason is under investigation * SECCHI-B software load * Had instances when the DSN transmitters were down before the start of the pass. Establishing commanding requires a sweep of the frequencies, during which time data is lost. Loss of data is minimized by waiting until SSR playback is done. Week 2007-01 * Behind spacecraft at 720 kbps, with typically 3 hour passes. After S2 will move to 4 hour passes. Passes are not always 24 hours apart--the requirements are that the passes are within 36 hours of each other. One issue driving the pass schedule is that both northern and southern hemisphere stations are needed on a regular basis for tracking purposes. * Currently using in-situ double playback, which doesn't always finish. (Days 361, 364). Looking into options about setting pointers to alleviate the problem. * SECCHI would like to postpone the SECCHI-driven EUVI off-point observations but keep the spacecraft driven off-point on January 5th. The starting time has been moved back to 15:55 UT. * SECCHI would also like to postpone the stepped calibration roll until after the spacecraft is back to 720 kbps. * Peak power test on B went well--will not have to be repeated. * STE-B offpoint maneuver ready to go. Scheduled for Friday, Jan 5, starting at 16:55 UT. Makes a 5x5 raster ranging from -2 to +2 degrees in Y,Z in 1 degree increments. SECCHI will close the COR1 and COR2 doors, but may take EUVI images. APL will send out a schedule of events for the maneuvers to the instrument teams. * Behind will stay at 720 kbps until Jan 13 when it drops to 480 kbps. It will be at 480 kbps on Jan 13, 14, and 16. The rate is 720 kbps on Jan 15 because a 70 meter antenna is being used. Week 2 * Will switch to HGA on Ahead on Monday. Considering swapping A & B tracks on Monday. * Behind will have an A5+ burn on Monday at 19:00 UT, with a backup on Jan 11. This will be a delta-V of ~1 m/s with a burn duration of about 1 minute. The spacecraft will slew 27 degrees from the sun line. * The HI-B door opening is rescheduled for Jan 11 to give sufficient time to ensure that no more maneuvers will be needed. * IMPACT needs to wait for go-ahead from SECCHI for the SIT/SEPT door cover openings. Plan to open HI early in the pass, SIT/SEPT late in the pass. * HGA calibration on Behind, Jan 12. Requires reverse polarization. Telemetry rate will be only 6 kbps on LGA for first 10-15 minutes, then switch to HGA at 720 kbps. R/T telemetry will start once on HGA. Pass duration is 6 hours. Also require 20 kWatt uplink power to close link. Week 3 * Another HGA calibration on Behind, Jan 18, with same comments as above. * S2 lunar swing-by on Behind, Sunday, Jan 21 at 08:58 UT. Altitude will be about 7000 km. The swingby will impart about 700 m/s of delta-V. Behind will have an orbit of 389 days. Other notes * No SECCHI R/T commanding will be needed for lunar transit, Feb 25. * Ahead momentum dump expected in week 4; Behind might be around Jan 30. * Behind will start using the HGA about a week after the S2 swingby. Will initially require reverse polarization on all passes. * SECCHI will need to pick dates for the HI rolls, and then determine the new roll angles based on the dates. * Mission Design requests that an S2- maneuver be scheduled Jan 15 in case the A5+ maneuver doesn't work. COORDINATED OBSERVATIONS ------------------------ ------------------------------------------------------------------------------- Scheduled activities for Week 01: M Jan 01 (001) T Jan 02 (002) Behind: Power tracking test, 45 degree off-point W Jan 03 (003) T Jan 04 (004) Ahead: HGA calibration F Jan 05 (005) Ahead: EUVI flat field calibration -- S/C driven Behind: IMPACT STE Offpoint 16:55 UT (TBC) S Jan 06 (006) Ahead: Switch downlink rate to 360 kbps S Jan 07 (007) ------------------------------------------------------------------------------- Scheduled activities for Week 02: M Jan 08 (008) Behind: A5 Prime Delta-V Maneuver Ahead: Switch to high gain antenna T Jan 09 (009) W Jan 10 (010) T Jan 11 (011) Behind: A5 Backup Delta-V Maneuver Behind: Open SECCHI/HI baffle cover, first light Behind: Deploy IMPACT SIT and SEPT covers F Jan 12 (012) Behind: HGA calibration S Jan 13 (013) S Jan 14 (014) Notes: * Hinode/SOHO/TRACE campaign - high temperature jets in polar coronal holes, Jan 8-21 * Behind at 480 kbps June 13, 14 ------------------------------------------------------------------------------- Scheduled activities for Week 03: M Jan 15 (015) T Jan 16 (016) W Jan 17 (017) T Jan 18 (018) Behind: HGA calibration F Jan 19 (019) S Jan 20 (020) S Jan 21 (021) Behind: S2 - second lunar swingby Notes: * Hinode/SOHO/TRACE campaign - high temperature jets in polar coronal holes, Jan 8-21 * Behind at 480 kbps June 16 ------------------------------------------------------------------------------- Scheduled activities for Week 04: M Jan 22 (022) T Jan 23 (023) W Jan 24 (024) T Jan 25 (025) F Jan 26 (026) S Jan 27 (027) S Jan 28 (028) ------------------------------------------------------------------------------- Scheduled activities for Week 05: M Jan 29 (029) Behind: 2nd SWAVES smooth calibration rolls T Jan 30 (030) Behind: 3rd SWAVES smooth calibration rolls W Jan 31 (031) Behind: Switch to high gain antenna T Feb 01 (032) F Feb 02 (033) S Feb 03 (034) S Feb 04 (035) -------------------------------------------------------------------------------