STEREO Weekly Meeting Minutes for 2006-11-28 (Week 48) ANNOUNCEMENTS ------------- * The decision was made to continue with the nominal orbit plan for both spacecraft. * It was incorrectly stated in last week's minutes that the eclipse associated with P3 would occur during DSN coverage. This is not the case. * The SWAVES team now has their daily summary plots online at swaves.gsfc.nasa.gov. Click on "data" and "data plots". INSTRUMENT AND SPACECRAFT STATUS -------------------------------- * Last week both spacecraft had a problem where the SSR partitions were not always being emptied by the end of each pass. This was caused by an excess of data in the SECCHI partition. At the current telemetry rate of 360 kbps, and with the current pass duration, it's not possible to downlink a full SECCHI partition within a single pass. The playback system is designed to download the partitions proportional to their size so that any telemetry losses are distributed among all the partitions. With a full SECCHI buffer, the other instrument buffers were not completely downloaded during some of the passes, which meant that the other instrument buffers filled up and data was lost. The situation was resolved by Saturday, and the SECCHI team has instituted additional controls on their planning process to make sure this doesn't happen again. * All SECCHI decontamination heaters have now been turned off. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- * There was a 45 minute delay coming up on the DSN station on Day 326. The station stayed on longer to make up the difference. * The P3 perigee will occur tomorrow. Because of the 20 minute eclipse starting just after perigee, SECCHI and PLASTIC will be powered down during the inbound track. IMPACT and SWAVES will be left powered on. The P3 altitude will be 4200 km for Behind and 4400 km for Ahead. (The attitudes for P4 will be about 6000 km.) * The IMPACT MAG roll will start ~1 hour after perigee. PLASTIC and SECCHI power on may be delayed until after the roll. No changes in the power state will be made during the roll. * IMPACT requests that the MAG roll be repeated at P4. * All instruments will remain powered on for P4. There are no planned instrument power shutdowns after P3. * There are no additional planned maneuvers for Ahead. Week 49 * Behind will have a small maneuver at A4, on Dec. 6th. Depending on the results of that maneuver, there may be another maneuver after S1. * SECCHI plans to open their SCIP doors on Ahead on Monday, December 4th. The originally planned GT calibrations will be delayed one day. They may also wish to open the HI door on Ahead by Thursday. * Mission Operations will be uploading a modification to a GT offset parameter of about 1 arc minute. This will only affect initial acquisition. The upload will occur after the recovery from P3. * On Thursday, Dec 7th, both spacecraft will start broadcasting space weather beacon telemetry between the tracks. The beacon telemetry will be convolutional 1/6th at 633 bps. Ephemeris and viewperiod products are now available on the SSC website for the beacon groundstations, and communication testing is going on between NOAA and Goddard. * There will be unattended DSN tracks for ranging purposes next week. During these tracks the telemetry rate will be 360 kbps, and instruments will be able to see their realtime telemetry. * On Friday, December 8th, there will be a calibration of the High Gain Antenna. This will involve small rolls of up to +/- 2 degrees around the Sun pointing direction. The calibration takes 90 minutes and will be performed first on Ahead in the morning, and on Behind in the afternoon. At each roll position, the HGA will step through a series of gimbal angles, dwelling 2-3 minutes at each location. SECCHI is planning on taking advantage of this opportunity to do some calibrations. * The DSN schedule for next week is still under review. As the maneuvers come to a close, the schedules will become more reliable. Week 50 * The P4 perigee occurs Dec 12. The first lunar swingby occurs December 15. * The post-track space weather beacon broadcast will not occur for about two days centered around P4. Other * SWAVES asked about the status of a problem with the Command History files. Currently the APIDs are being listed in these files incorrectly. No other data products are affected. A CR is in to get this corrected. Once the software is corrected, older files will be reprocessed. * The SIT team requests that their HV ramp up be delayed from week 49 to week 51 for scheduling reasons. * SECCHI points out that the HI doors should be opened before the SIT covers are deployed, in case the HI door doesn't completely open and the spacecraft needs to be shaken to remedy the problem. The Ahead HI door is anticipated to be opened next week, and the Behind HI door will be opened after the last delta-V maneuver. * The three HI calibration rolls are being tested on the simulator this week. The HI stray light offset maneuver still needs to be developed. * A maneuver is being developed to analyze the STE problem on the Behind spacecraft. This maneuver will explore a +/- 10 degree grid in the Y-Z plane to look for the STE sunshade. COORDINATED OBSERVATIONS ------------------------ Scheduled activities for Week 48: M Nov 27 (331) T Nov 28 (332) W Nov 29 (333) P3 Perigee IMPACT MAG rolls, HGA end-to-end slew T Nov 30 (334) F Dec 01 (335) S Dec 02 (336) S Dec 03 (337) ------------------------------------------------------------------------------- Scheduled activities for Week 49: M Dec 04 (338) Ahead: Open EUVI, COR1, & COR2 doors, first light T Dec 05 (339) Ahead: 2nd GT Calibration W Dec 06 (340) A4 Apogee Ahead: 3rd GT Calibration Behind: A4 Prime Delta V Maneuver T Dec 07 (341) Ahead: Open HI baffle cover door, first light (TBC) Behind: A4 Backup Delta V Maneuver Both: Start space weather beacon broadcast post-track F Dec 08 (342) HGA calibration S Dec 09 (343) Behind: 2nd GT Calibration S Dec 10 (344) Behind: 3rd GT Calibration ------------------------------------------------------------------------------- Scheduled activities for Week 50: M Dec 11 (345) T Dec 12 (346) P4 Perigee W Dec 13 (347) T Dec 14 (348) F Dec 15 (349) S1 first lunar swingby S Dec 16 (350) S Dec 17 (351) Notes: * No space weather beacon broadcast Dec 12-13. ------------------------------------------------------------------------------- Scheduled activities for Week 51: M Dec 18 (352) T Dec 19 (353) Behind: First SWAVES smooth calibration rolls W Dec 20 (354) T Dec 21 (355) Behind: S1+ Prime Delta V Maneuver F Dec 22 (356) S Dec 23 (357) Behind: S1+ Backup Delta V Maneuver S Dec 24 (358)