It’s here.

Why does the orbit have this shape? It’s because SDO takes so many large images that it has to have its own ground station to receive all that data (around 1.5 TB/day). In order to keep the flow of data running off the spacecraft, its geosynchronous orbit was designed to maintain contact with the ground station. For more detail, please go to http://sdo.gsfc.nasa.gov/mission/project/specs.php.