IRIS is on a mission to study the "interface region," a layer of the sun's atmosphere where most solar ultraviolet radiation is generated. Researchers are keen to study the interface region because it is probably the energy source for the sun's mysteriously-hot outer corona.
A good way to understand IRIS's uniqueness is to compare it to NASA's Solar Dynamics Observatory (SDO). While SDO sees the entire sun, IRIS going to look closely at only 1 percent of the sun's surface, discerning features as small as 150 miles across. "IRIS almost acts as a microscope to SDO's telescope," explains mission manager Jim Hall.
"IRIS will show the solar chromosphere in more detail than has ever been observed before," says Adrian Daw, deputy project scientist. "My opinion is that we are bound to see something we didn't expect to see."