The Solar Dynamics Observatory photographs the Sun every twelve seconds in ten wavelengths simultaneously, producing about a terabyte and a half of data per day — more than any previous NASA science mission by a wide margin, and enough that it required its own dedicated ground station in New Mexico because the normal network could not absorb it.
The reason for that firehose is that solar activity happens fast. Flares evolve in seconds, and understanding the magnetic reconfiguration that drives them requires continuous high-cadence imaging rather than snapshots. SDO flies in an inclined geosynchronous orbit so it can downlink continuously to one antenna.
Its imagery is the most widely reproduced solar photography ever taken. The extreme-ultraviolet views of the corona — vast arcades of magnetic loops shifting, snapping and erupting — have become the visual shorthand for the Sun in essentially all public communication.
Scientifically it maps the magnetic field across the visible surface continuously, measures the Sun's total energy output, and uses helioseismology to see structures beneath the surface, including active regions detected on the far side days before they rotate into view.
It has run since 2010 through a complete solar cycle and into the next, and its archive is the reference dataset for solar physics. Its practical output is space-weather forecasting: essentially every warning issued about an incoming solar storm begins with an SDO image.
