The Cassini Orbiter's mission consists of delivering a probe (called Huygens, provided by ESA) to Titan, and then remaining in orbit around Saturn for detailed studies of the planet and its rings and satellites.
Cassini is the largest interplanetary spacecraft ever constructed by NASA.
Titan and Enceladus Mission
Primary goals are to understand the atmosphere, surface and interior, to determine the chemistry, and to derive constraints on the origin and evolution of Titan and of the saturnian system as a whole, with an emphasis on Enceladus.
Note: Following the joint ESA-NASA decision in February 2009 to further pursue the Europa Jupiter System Mission (EJSM), the studies concerning the TandEM mission concept within ESA have been terminated.