地平线系列：再见卡西尼号，你好土星

由众多科学家和工程师研发接近30年的“卡西尼号”太空探测器在经过长达近7年的漫长太空旅行之后，顺利进入环绕土星转动的轨道，开始对土星大气、光环和卫星进行历时4年的科学考察。卡西尼号”还携带了探测土星最大卫星土卫六的探测器，取名为“惠更斯号”。在探测任务20年后，卡西尼号土星探测器燃料将尽，科学家控制其向土星坠毁，在此之后，卡西尼号与地球失去联系，它进入土星大气层燃烧成为土星的一部分。在卡西尼号毁灭的最后一秒钟，它都坚守使命，往地球传输数据，最后才壮烈冲向大气层。This documentary is about the end of the Cassini-Huygens space-research mission commonly called 'Cassini'. This was a collaboration between 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. From its launch in October 1997 to nearly 20 years later in September 2017, the craft has nearly run out of fuel and reached the end of its original and extended missions. 'Horizon' (BBC) visits some of the main scientists working on the 'Cassini' program, and find out their roles and discoveries in this mission. Finally, they meet at a special farewell ceremony at the 'NASA - Jet Propulsion Laboratory' for Cassini's 'Grande Finale'.