In 1997, a spaceship called Cassini was sent to explore Saturn (土星) and its moons. Now Cassini's mission (使命) has come to an end. Scientists made it fall and bum up in 2017. But before that happened, the spaceship had made many trips between Saturn and its rings, sending photos and other information back to the Earth.
Cassini was a project carried out by NASA, the European Space Agency and the Italian Space Agency. It took Cassini about seven years to reach Saturn.
Scientists have learned many exciting things from Cassini. In 2005, Cassini sent a space probe (探测器) to Saturn's largest moon, Titan, so scientists could get a closer look at the moon's surface. One of the most important discoveries Cassini made was that there is warm liquid water (液态水) under the ice that covers one of Saturn's smaller moons, Enceladus. Scientists believe conditions on Enceladus could be similar to the conditions that led to the development of life on Earth.
Cassini's mission was supposed to be ended in 2008, but because it was still in good shape, scientists increased its life to 2017. Cassini performed the last task of its mission on September 15, 2017.
When Cassini ran out of its fuel (燃料) and entered Saturn's atmosphere (大气层), it burned up. Scientists said it was necessary for Cassini to be totally destroyed (毁坏) so there was no chance that microbes (微生物) from the Earth could be harmful to any possible life on Saturn.
