On-Orbit Testing of SDO, March 28–April 25, 2018

SDO uses two high-gain antennas (HGAs) on the spacecraft to maintain continuous contact with the SDO ground station in New Mexico. Should one of those antennas fail we would have to roll the spacecraft to a variety of position angles during the year to keep the remaining HGA in contact with the ground station. The SDO Team will be testing the procedures needed to run SDO on a single HGA from March 28, 2018, to April 25, 2018.

During the test the roll angle of SDO will vary from 0 to 180 degrees. Near-realtime images from SDO may appear with the incorrect position angle, similar to what happens during an instrument calibration. To ensure you have correctly aligned science data, please use the exported images from the JSOC or the SSW IDL routines aia_prep.pro and hmi_prep.pro. If you use other software for data analysis, make sure you properly account for the value of the CROT2 when preparing the data.

Remember: This is only a Test!"

Happy Pi Day!

Although there isn't a major geomagnetic storm happening today (and none expected tomorrow), here is a lovely picture of the Sun showing a coronal hole. The high-speed plasma streaming out of this coronal hole will probably hit the Earth and create some lovely aurora, but a geomagnetic storm is not expected.

Enjoy Π Day!

Station Keeping Maneuver #16 Today

SDO will perform station-keeping maneuver #16 today. The maneuver begins at 22:12 UTC (5:12 pm ET) and lasts until 22:56 UTC (5:56 pm ET). During the maneuver science data may be blurry or unavailable.

Station-keeping maneuvers are performed to keep SDO inside of its box in the geostationary belt. Even though SDO’s orbit is inclined 28° to the equator (where geostationary satellites orbit), we pass through the geostationary belt twice each day. We must stay inside our longitude box to avoid interfering with our neighbors. SK maneuvers happen about twice each year.

Happy 8th Birthday, SDO!

It was a cold day at Cape Kennedy as SDO rose slowly into the sky. Eight years later, SDO has sent over 260 million images of the Sun to the ground. Over 3000 scientific papers have described how the Sun's magnetic field is created and destroyed. We have a large number of citizen scientists who study our images, especially using HelioViewer.

SDO still produces high quality data of the Sun every day. Even Solar Cycle 24 fades from view, we are watching the polar region magnetic fields grow. Large coronal holes can often be seen in the AIA coronal images. Solar Cycle 25 will soon be visible. SDO is ready!

2018 Maneuvers, Past and Future

SDO ran a number of maneuvers during January 2018. Science data may be unavailable or blurry on days when a maneuver is run. During eclipse season the Earth blocks the Sun for up to 72 minutes each day around 0700 UTC (2:00 am ET). This is also midnight Mountain Time, the timezone of the SDO ground station.

• 01/03/18: RWA Jitter Test Successful: Instruments reported no blurring in images; ISS performance looked reasonable.
• 01/17/18: EVE Cruciform Successfully Executed
• 01/24/18: HMI roll, starting at 1500 UTC (10:00 am ET)
• 02/10/18: Spring 2018 Eclipse Season Begins
• 02/14/18: Stationkeeping Maneuver #16 (2234 UTC, 5:34 pm ET)
• 03/05/18: Spring 2018 Eclipse Season Ends

Above is a movie in AIA 171 Å showing the effects of the EVE Cruciform on January 17, 2018. During the HMI Roll the Sun appears to rotate.

Server maintenance, January 11, 2018

Today, January 11, 2018 at approx. 1:30 pm the SDO website will undergo server maintenance. The website will still be operational. However, images, movies, and data will not be available for some time.

Momentum Management Maneuver #31

SDO will perform Momentum Management Maneuver (Delta-H) #31 between 1919 and 1953 UTC (2:19-2:53 pm ET) today. We will fire the thrusters to bring the reaction wheels to their planned speeds. Science data may be unavailable or blurry during the maneuver.