STEREO Weekly Meeting Minutes for 2006-11-21 (Week 47) ANNOUNCEMENTS ------------- * Perigee P3 is November 29. * There will be no A3+ maneuvers, and probably no P3 maneuvers. * The Early Operations Schedule has been updated and is available on the STEREO Data Server. * The STEREO Data Server has a new Data Return Report page where one can find out how much data was downloaded for each instrument. INSTRUMENT AND SPACECRAFT STATUS -------------------------------- * Last week did long A2+ maneuvers, and shorter P2 maneuvers, on both spacecraft. Maneuvers went well. Ahead is now on track for the S1 encounter, and no more maneuvers are expected for Ahead barring orbit changes. Behind needs at least one more maneuver, currently scheduled for Dec. 6 with a backup on Dec. 7, at 20 UT both days. * Performed a practice IMPACT MAG roll and HGA slew. Preliminary indications are that the data look good. No obvious signals were seen from the HGA--data analysis is still proceeding. SECCHI also exercised its mechanisms, but the data are still awaiting download from the spacecraft. The same maneuvers are scheduled to occur during the P3 perigee (see below). * After the A2+ maneuver both spacecraft had an autonomy rule fire. This uncovered a software bug with transaction counters incrementing. The problem was cleared when instruments were turned off for the A2+ and P2 maneuvers, as expected. A future onboard software release should fix this problem. DISCUSSION AND OPERATIONS CONSTRAINTS ------------------------------------- * Weekly schedules are not yet out because DSN schedules are still being negotiated. Looking to keep most P3 coverage. There is a short gap in DSN before the perigee. There are 10 hour tracks both inbound and outbound of P3. Staffing has to be worked out. * There will be a 20 minute eclipse just after perigee. This will occur during DSN coverage * The new Early Operations Schedule lists which instruments are off for P3. * Mission Design has been looking at possible orbit changes which would lower the maximum aphelion distance on the Behind spacecraft. This has the side effect of providing a transit of the Sun by the Moon as seen from Behind several weeks after S2. Mission Design is also looking at possible maneuvers to target a Mercury transit by Ahead--this would require two additional maneuvers. Such transits could be useful for SECCHI stray light calibrations. The SECCHI team expressed that they had requested Mission Design to look for possible transits, but had not actually requested maneuvers to target them. SECCHI cannot open the HI doors until all maneuvers are complete. * The IMPACT MAG rolls are scheduled for the outbound side of P3. IMPACT wants to stay on, and requests that they take priority over SWAVES for this perigee. The roll is scheduled to take place in the magnetosphere below 50,000 km. IMPACT prefers the roll start 1 hour after perigee, which matches Mission Ops plans. The rolls will occur almost simultaneously on both spacecraft, about a half-hour apart. * IMPACT would like for SECCHI to exercise. its mechanisms again as it did for the last roll. SECCHI would have to be powered on to take part in the MAG tests. It takes SECCHI at least an hour to come back up. No changes in instrument power status should occur during the MAG test, so instruments have to be powered back on either before the roll or after the HGA slew. IMPACT sees no problem with a delay in the SECCHI part of the test. The inbound and outbound tracks are both 10 hours long, so there should be sufficient time to bring both back up and make the tests. * SECCHI is disabling the COR1 and COR2 decontamination heaters today. The EUVI and HI heaters will be turned off either Monday or Tuesday. SECCHI will make measurements to characterize the CCDs as the temperatures decrease. * The current schedule calls for SECCHI to be performing mechanism testing next week. However, SECCHI may want instead to push forward the opening of the Ahead SCIP doors to the end of week 48. The mechanism tests can be performed after the doors are open. The opening of the HI doors depends on knowing whether any more maneuvers are planned. Opening of the Ahead SCIP doors requires 93 kbps telemetry rate. SECCHI will communicate their plans to Mission Ops in sufficient time to schedule the proper telemetry rates. * PLASTIC continues to bring up their voltages. * SECCHI GT calibrations have been moved to week 49 to move them out of the weekend. Activities occurring near Christmas may also be moved to avoid the holiday. * DSN track schedules: - Tracks start serially today. Tomorrow will have early and late tracks. There will be no tracks Thanksgiving day to allow operations staff to take the day off. Coverage will pick up again on Friday to keep within the 36 hour constraint. - Next week will have 3 hour tracks except near perigee. - Additional unattended tracks are scheduled for tracking purposes. Instruments can receive realtime telemetry, but there will be no commanding or dumping of the onboard recorder. - During week 49, there will be additional unattended tracks. There will be 3 hour attended tracks every day for the Ahead spacecraft, usually on the Goldstone station but occasionally on Canberra. Behind will have more tracks because of the maneuver. * The instrument teams want to know when the system power plan for P3 will be announced. Operations will discuss with Systems today. The current plan is to do the same as during P2, except that IMPACT may be powered on instead of SWAVES. * IMPACT would like to do a diagnostic maneuver on the Behind spacecraft to explore their problems with the STE. They want to scan the sky to see if their sunshade is misaligned. The details of this maneuver need to be worked out, but will probably involve both rolls and off-points. The question was raised about what would be the thermal effects. The effects should be similar to what is seen during thruster firings, so long as the maneuver is short. * HI calibration maneuver status: The scripts for the 180 degree and flat field roll maneuvers have been written but not yet tested. No work has been done yet on the 90 degree roll and stray light off-point maneuvers. APL is still awaiting word from the STEREO project about these maneuvers, but is pressing ahead with their implementation as time permits. * Leonid showers: STEREO passed through the Leonid stream last weekend. It is not very dense, but can still pose problems, chiefly spacecraft charging (problem for high voltage instruments) and danger of damage to exposed optics and solar panels. No effects were noticed on STEREO during the Leonid passage. In the future the Leonids will be mostly an issue for Ahead because of the location of the stream. APL will keep track of future Leonid and other meteor stream events. * The SSC asked which instruments are currently producing space weather packets. IMPACT and PLASTIC are generating these packets automatically, but not all the contents are meaningful yet. PLASTIC doesn't expect meaningful beacon telemetry for another couple of weeks. Some of the IMPACT beacon data may be meaningful already, but other telemetry points are not yet ready. SECCHI won't be ready to produce space weather telemetry until the end of their commissioning, but may be able to produce a small amount of test data before that. Nobody from SWAVES was present to discuss their space weather packets. The SSC would like to start testing their beacon processing code--calibrated data are not required at this stage. COORDINATED OBSERVATIONS ------------------------ Scheduled activities for Week 47: M Nov 20 (324) IMPACT MAG rolls, HGA end-to-end slew T Nov 21 (325) W Nov 22 (326) T Nov 23 (327) A3 Apogee F Nov 24 (328) S Nov 25 (329) S Nov 26 (330) ------------------------------------------------------------------------------- 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: 2nd GT Calibration T Dec 05 (339) Ahead: 3rd GT Calibration W Dec 06 (340) A4 Apogee Behind: A4 Prime Delta V Maneuver T Dec 07 (341) Behind: A4 Backup Delta V Maneuver Ahead: Open EUVI, COR1, & COR2 doors, first light Both: Start space weather beacon broadcast post-track F Dec 08 (342) S Dec 09 (343) Behind: 2nd GT Calibration S Dec 10 (344) Behind: 3rd GT Calibration -------------------------------------------------------------------------------