The CASSINI/Composite Infrared Spectrometer (CIRS) is a major science instrument aboard NASA's Cassini orbiter mission to Saturn. It measures the infrared energy from Saturn, its rings and its moons, especially Titan. This allows scientists to study the thermal structure and composition of the objects in the Saturnian system. CIRS was built by NASA/Goddard Space Flight Center, with significant hardware contributions from England and France.