<Tr> <Td_colspan="2"> Flagship Program ← Galileo Mars Science Laboratory → </Td> </Tr> <P> The Cassini--Huygens mission (/ kəˈsiːni ˈhɔɪɡənz / kə - SEE - nee HOY - gənz), commonly called Cassini, was a collaboration between NASA, the European Space Agency (ESA), and the Italian Space Agency (ASI) to send a probe to study the planet Saturn and its system, including its rings and natural satellites . The Flagship - class unmanned robotic spacecraft comprised both NASA's Cassini probe, and ESA's Huygens lander which would be landed on Saturn's largest moon, Titan . Cassini was the fourth space probe to visit Saturn and the first to enter its orbit . The craft were named after astronomers Giovanni Cassini and Christiaan Huygens . </P> <P> Launched aboard a Titan IVB / Centaur on October 15, 1997, Cassini was active in space for nearly 20 years, with 13 years spent orbiting Saturn, studying the planet and its system after entering orbit on July 1, 2004 . The voyage to Saturn included flybys of Venus (April 1998 and July 1999), Earth (August 1999), the asteroid 2685 Masursky, and Jupiter (December 2000). Its mission ended on September 15, 2017, when Cassini's trajectory took it into Saturn's upper atmosphere and it burned up in order to prevent any risk of contaminating Saturn's moons, which might have offered habitable environments to stowaway terrestrial microbes on the spacecraft . The mission is widely perceived to have been successful beyond expectation . Cassini - Huygens has been described by NASA's Planetary Science Division Director as a "mission of firsts", that has revolutionized human understanding of the Saturn system, including its moons and rings, and our understanding of where life might be found in the Solar System . </P> <P> Cassini's original mission was planned to last for four years, from June 2004 to May 2008 . The mission was extended for another two years until September 2010, branded the Cassini Equinox Mission . The mission was extended a second and final time with the Cassini Solstice Mission, lasting another seven years until September 15, 2017, on which date Cassini was de-orbited to burn up in Saturn's upper atmosphere . </P>

When did the cassini spacecraft arrived at saturn