NASA's Cassini spacecraft is preparing for its final plunge into Saturn, after spending two decades travelling around the planet. The grand finale of the spacecraft is to begin on April 26, when the Cassini will soar through the first of Saturn's rings. "No spacecraft has ever gone through the unique region that we'll attempt to boldly cross 22 times," Thomas Zurbuchen of NASA said. The final death plunge of Saturn is expected to take place on September 15.