The Saturn planet was explored by Cassini Mission launched by NASA, which ended in September 2017. Launched on October 15, 1997, the mission entered the orbit around the Saturn on June 30, 2004, carrying the European Huygens probe. Its key discoveries included the global ocean with indications of hydrothermal activity within Enceladus, and liquid methane seas on Titan. The mission ended on September 15, 2017.