Mission to Saturn (1997–2017) Cassini–Huygens, commonly called Cassini, was a joint space-research mission by NASA, the European Space Agency (ESA), and the Italian Space Agency (ASI) to send a space probe to study the planet Saturn and its system, including its rings and natural satellites. The Flagship-class robotic spacecraft comprised both NASA's Cassini space probe and ESA's Huygens lander, which landed on Saturn's largest moon, Titan. Cassini was the fourth space probe to visit Saturn and the first to enter its orbit, where it stayed from 2004 to 2017. The two craft took their names from the astronomers Giovanni Cassini and Christiaan Huygens. 405,959 views on April 26, 2017 — Wikipedia's most-read article that day. Also most read: 13 Reasons Why, Christina Grimmie, Jonathan Demme, Albert Einstein. Wiki link