STEREO Weekly Meeting Minutes for 2006-12-12 (Week 50) ANNOUNCEMENTS ------------- * The Behind orbit will be altered so that the moon will transit the Sun as seen from the spacecraft. This will be implemented in a S1+ maneuver on Dec. 21, pending official written approval by Goddard. INSTRUMENT AND SPACECRAFT STATUS -------------------------------- * Both spacecraft preforming well A4+ maneuver (Behind) went well. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- Week 49: * Last week the EUVI and Cor1 and Cor2 instrument covers were removed. there was a GT calibration on Ahead * Space Weather Beacon was started last week, although it was turned off since yesterday (Dec. 11) until Dec. 13. RAL is trying to receive the Beacon data. * A test of the GMC and GT jitter correction was done and seemed to work well. It is not yet known if this improves SECCHI image quality. The amount of jitter has been varying. It was high on Sunday. This is probably due to structural oscillation modes triggered by particular wheel velocities. There will be tests to determine which wheel velocities cause problems so that they can be avoided. For such tests it would be good to get extra telemetry for the Guide Telescope. * On Sunday a track for Behind was lost due to a power outage at Goldstone, but this was made up on the track immediately following. Week 50: * Yesterday was a peak power tracking test on ahead. The spacecraft rolled 45 degrees again the Z axis. The same test for Behind is scheduled for Jan. 3 or 4. * P4 was earlier today. It was followed by IMPACT MAG rolls, HGA end-to-end slew and auto-track test on both spacecraft. All went well. * Tomorrow (Dec. 13) Ahead: Momentum dump on ahead at 12:30 UT. Using B thrusters for 2.5 - 5 min. 13:00 HI-A cover opening. Ahead will be rolled so there is a chance Earth will be in the HI field of view. Behind: Track from 10:40-14:00 UT 11:20 - 11:30 start opening SECCHI/EUVI,Cor1, and Cor2 doors SECCHI will operate Ahead from NRL and Behind from APL The GT calibration originally scheduled for this day should be rescheduled. * Thursday (Dec. 14) Open Ahead IMPACT/SEPT and SIT doors. High rate data required. Ahead GT Calibration * Friday (Dec. 15) is the 1st Lunar Swing by (S1) at roughly 21:30 UT. The swing-by occurs in the middle of a track. * Saturday (Dec. 16) is a Behind GT calibration Week 51: * The 1st of 3 SWAVES calibration rolls. Ahead: Monday Dec. 18, Behind: Tuesday Dec. 19. This is an X-axis roll. The Space Weather beacon may drop in and out during this time. * There is also a time update being planned on both observatories on Monday, Dec 18th. * On both Dec. 20 and 21 there will by HGA calibration 2 deg rolls about X axis for Ahead. These will take about 1.5 hours (these were originally scheduled for Dec. 18th and 19th), SECCHI wants to know the roll details so that they can do HI imaging during the roll. There will also be GT calibrations on both days. * At the SWG meeting it was decided that the Behind orbit will be changed to option 2a, which will result in observations of the lunar transit by SECCHI and improved observations from GT and HI. This is done pending assurances from APL that there would be no changes in the solar illumination pattern on any part of the spacecraft. This assurance has been given. APL will need written confirmation from the correct Goddard official to actually go ahead with the change. The change will be implemented during a S1+ maneuver on Dec. 21. The maneuver will be with the B thrusters on the Z+ side of the spacecraft. The backup date in Dec. 23. Cor1 and cor2 doors will be closed for the maneuver. Week 52: * No instruments are planning any commanding on Dec. 25 GT Calibration scheduled for Dec. 26 Week 1, 2007: * Jan. 3 or 4 will be the 45 degree roll peak power tracking test for Behind. * IMPACT is using these peak power tracking tests to substitute for a previously suggested 90 degree off point for MAG. They think at this point that they do not want to do the full 90 degree off point they originally proposed. COORDINATED OBSERVATIONS ------------------------ Scheduled activities for Week 50: M Dec 11 (345) Ahead: Power test, 45 degree off-point Both: Auto track on HGA test Both: Stop space weather beacon broadcast post-track T Dec 12 (346) P4 Perigee, IMPACT MAG rolls, HGA end-to-end slew W Dec 13 (347) Ahead: Momentum Dump 13:00 UT Ahead: Open HI baffle cover door, first light Behind: Open EUVI, COR1, & COR2 doors, first light Both: Restart space weather beacon broadcast post-track T Dec 14 (348) Ahead: SECCHI GT calibration 14:00 UT Ahead: Open IMPACT SIT and SEPT covers F Dec 15 (349) S1 first lunar swing-by S Dec 16 (350) Behind: SECCHI GT Calibration S Dec 17 (351) ------------------------------------------------------------------------- Scheduled activities for Week 51: M Dec 18 (352) Ahead: First SWAVES smooth calibration rolls T Dec 19 (353) Behind: First SWAVES smooth calibration rolls W Dec 20 (354) Behind: SECCHI GT calibration 20:00 UT Ahead: HGA calibration T Dec 21 (355) Behind: SECCHI GT calibration 11:05 UT Behind: S1+ Prime Delta V Maneuver Ahead: HGA calibration F Dec 22 (356) S Dec 23 (357) Behind: S1+ Backup Delta V Maneuver S Dec 24 (358)