Cassini Space Mission(NASA): About the Mission After two decades in space, NASA's Cassini spacecraft is nearing the end of its remarkable journey of exploration. Having expended almost every bit of the rocket propellant it carried to Saturn, operators are deliberately plunging Cassini into the planet to ensure Saturn's moons will remain pristine for future exploration—in particular, the ice-covered, ocean-bearing moon Enceladus, but also Titan, with its intriguing pre-biotic chemistry. Beginning in 2010, Cassini began a seven-year mission extension in which it completed many moon flybys while observing seasonal changes on Saturn and Titan. The plan for this phase of the mission was to expend all of the spacecraft's propellant while exploring Saturn, ending with a plunge into the planet's atmosphere. In April 2017, Cassini was placed on an impact course that unfolded over five months of daring dives—a series of 22 orbits that each pass between the planet and ...