The Cassini spacecraft will to be launched on its mission to Saturn in October 1997. Upon arrival in 2004, Cassini will begin a four-year tour of the Saturnian system, the first visit to that planet since Voyager. Among several remote sensing instruments in its payload, the spacecraft will carry the Composite Infrared Spectrometer (CIRS), to study the atmospheres and surfaces of Saturn and its moons. CIRS will retrieve temperatures and gas compositions in the atmospheres of Saturn and its largest moon, Titan, from deep in their tropospheres to high in their stratospheres. CIRS will also investigate the thermal properties and composition of Saturn’s rings. Studies of Saturn and Titan will tell us about the formation and composition of the early solar system, the evolution of these two very different bodies along different paths, and how, at present, they change diurnally and seasonally. Spectra of the rings and the moon's solid surfaces will help determine their thermal characteristics, mineral compositions, and geological evolutions.
