|Magnetic Flux on the surface of the Sun. NASA photo.|
The SDO (Solar Dynamics Observatory) is in a geosynchronous orbit, but it is not stationary relative to the Earth's surface like the communications satellites. The plane of its orbit is inclined relative to the Earth so that it almost always has the sun in view. However, in three months things will have changed 90 degrees and the satellite will now be passing through the Earth's shadow once a day.
|One of two antennas dedicated to round-the-clock reception of data from the Solar Dynamics Observatory. Each antennae is almost 60 feet in diameter. Photo by Tim C. Gregor.|
A terabyte of data used to be large. Now you can buy 3 terabyte disk drives for $100. Still, SDO is going to be filling them up quickly, dumping a boat load of data down the link every day, day after day, year after year. And this is just one satellite. NASA must have a really big server farm.