SDO Weekly Report for March 29, 2012

The FOT performed the SDO Station Keeping maneuver number 4 (SK4) on 3/28. We used 69 grams of propellant to keep SDO within our assigned box.

An HMI roll was performed this morning (April 4) starting at 0550 UTC.

AIA images are again current.

SDO Weekly Report for December 2, 2011

The FOT and Science Teams monitored Reaction Wheel speeds and instrument performance as the maximum wheel speeds on wheels 3 and 4 slowly rose above 850 RPM. Wheel speed predicts have indicated that the wheel speeds should soon begin reducing on their own, but this has not yet happened. A momentum unload has been scheduled for 12/7 and will be performed if the wheel speeds have not begun to reduce on their own by then.

On 12/1 the FOT began seeing sustained winds of approximately 45 mph at both SDO1 and SDO2 antennas. They contacted SDO personnel at WSC who indicated the latest forecast for overnight was for gusts up to 85 mph. The FOT alerted SSMO management and the Mission Director (MD). A teleconference was held with the SDO Project Scientist, the FOT, the MD and SSMO management to plan for the extreme wind event. It was decided to staff overnight in the MOC and at WSC. After winds at SDO2 exceeded 65 mph for 3 samples within a 5 minute period, SDO2 was automatically braked as of 02:35 GMT on 12/2. The highest wind speed recorded at SDO2 was 74 MPH. After the winds died down, SDO2 was brought back online as of 05:50 GMT with manual workarounds. The automatic recovery of SDO2 failed due to ACA faults, apparently caused by antenna motion while it was braked. SDO1 only experienced a few wind speed readings over 65 MPH and remained on point. However, due to the very high winds, there were Ka band dropouts at SDO1 while SDO2 was braked. There were also subsequent short periods of simultaneous data loss at both SDO1 and SDO2 because of the very high winds. Preliminary estimates put the data capture for 12/2, Day Of Year 336, at 94 percent. Lessons learned from this exceptional wind event will be discussed next week.

SDO Weekly Report for October 7, 2011

The Flight Operations Team monitored the end of eclipse season on 10/4. The FOT postponed lowering the spacecraft bus voltage to accommodate a request from the Atmospheric Imaging Assembly (AIA) team to provide more heater power for a 36 hour bake-out of ATA #4. The bake-out was performed successfully on 10/4-10/5. The bus voltage was reduced on 10/6 to the normal full sun voltage to maintain the battery at 60% state of charge.

SDO Weekly Report for September 16, 2011

The Flight Operations Team prepared for the third SDO orbit stationkeeping maneuver (SK3) planned for 9/21. The flatsat run was completed on 9/15 and the CAM materials were delivered on 9/16.

New weather monitoring stations were installed at the SDO1 and SDO2 antennas to replace units which failed during recent severe weather.

SDO Weekly Report for August 12, 2011

SDO2 antenna maintenance was performed on 8/7 and 8/10 to isolate and remedy low signal levels on the right hand circular polarization (RHCP) path. Maintenance was planned for 8/12 to complete the repair ahead of handover season, which begins on 8/15. However as of 8/15 the maintenance is waiting on availability of a cable; efforts to acquire the cable are underway.

SDO Weekly Report for July 22, 2011

On Wednesday July 20 SDO did two maneuvers, an EVE field of view from 1315-1600 UT and an HMI off point from 1630-1910 UT. During these maneuvers the near real time images look cut-off and some data may have been lost. An example of a shifted image is shown on the left. Unlike earlier maneuvers, where the image moved around in the picture, the NRT software is centering the image and we see the edge of the CCD as a straight line.

On 7/16 the MOC backup Real-Time system lost 3 hours of S-band data due to a line hit causing a socket disconnect. The primary string was unaffected so there was no impact.

We have been told that the electricity will be shut off in the room with the Goddard SDO computers this weekend. This means the website will be down from 6:00 am to as late as 3:00 pm ET. The instrument websites are not affected by this outage and neither is the satellite. Sorry for the inconvenience.

SDO Weekly Report for June 29, 2011

The FOT discovered a discrepancy between the Inertial reference Units (IRU) alignments and scale factor presently onboard in the Single Board Computer (SBC) Table 73 and those which were supposed to be in use. The differences are small, and the effects minimal, so the plan is to do nothing at this time, since time out of science mode (~ 1 hour) is required to validate an alignment table change per current procedures. The current plan is to wait until the next eclipse season this fall to correct the problem. An audit of all other alignment parameters has been started to look for any other discrepancies.

The FOT completed simulations for the momentum unload scheduled for 7/6 at 19:17 GMT. The Command Authorization Meeting (CAM) will be held on 7/5 after the weekly planning meeting.

SDO Weekly Report for June 2, 2011

Although solar activity remained low this week we did see a few interesting prominence eruptions.

On May 31 the SDO1 antenna data path experienced an apparent radio frequency interference (RFI) event that lasted several seconds. There was no data loss.


If you are in New York this weekend be sure to join SDO team members at the World Science Festival on Governor's Island. We will have solar telescopes, talks about the Sun by Dean Pesnell and Timothy Ferris, and other activities describing magnetism and solar observations. For a schedule of events visit the World Science Festival website. SDO is featured in the Science on Site: Explorations on Governors Island event, Saturday, June 4, 2011 10:00 AM - 6:00 PM. See you there!

SDO Weekly Report for November 19, 2010

Based on discussions with the science teams, it was decided to use the new offset procedure for future Lunar Transit operations to minimize instrument off-pointing during the transitions from Science to Inertial mode and back.

Obtained agreement from the HPA vendor to replace all DC fans with AC fans to improve reliability. The repairs will be done on a rotating cycle to continue operations while units are being repaired.

SDO Weekly Report for November 11, 2010

The second HGA handover season ended on November 1. Operations went smoothly throughout this handover season and another Lunar Transit on 11/6. The data capture completeness for October was 99.94% for all three Instruments. Only rain on DOY 278, a spacecraft station-keeping maneuver on DOY 279, and the HMI Roll calibration on DOY 285 kept us from 100%.

The Inertial/Science mode pointing test was run on Wednesday, 11/10 between 1800 to 1830 UTC. This tested the STOL procedure that redefines the target attitude to minimize the attitude shift between Science and Inertial modes is minimized. This will benefit future Lunar Transit operations.

The "Sun as an Andy Warhol Poster," made from an AIA image, can be seen in the background of an episode of The Big Bang Theory on CBS, with a short clip on Youtube.

SDO Weekly Report for November 4, 2010

The EVE cruciform was delayed for one day and performed on Thursday. Some of the images in Thursday's movies were taken when SDO was pointed away from the Sun so they are missing or have the stripes we saw last week.

The Instrument calibration activities were shifted this week to accommodate the 40-hour continuous observation campaign of the Hinode satellite observation. This was to study the emergence and disappearance of magnetic flux at the Sun’s disk center. EVE reported that there was some improvement in the MEGS-B performance after the previous CCD bakeout but they will return to a 24 hour bakeout during the next eclipse period. The FOT updated the jitter wheel speed limits to 850 rpm from the 380 rpm limit set prior to launch.