NASA’s Cassini mission to Saturn, launched October 17, 1997 and completed September 15, 2017, has made a wealth of phenomenal scientific discoveries that has rewritten the textbooks on the history and  evolution of the Saturnian system of satellites including Titan and Enceladus. In fact, Cassini discovered the now famous geysers on Enceladus that the spacecraft flew through and made in-situ measurements. Results indicate that the geysers are in fact water plumes emanating from deep thermal vents under the icy crust, reaching deep into space Geysers Enceladus. The Saturnian system of satellites is so exciting scientifically that NASA has already initiated a mission to land on methane-rich Titan with a hovercraft called DragonFly: https://www.nasa.gov/press-release/nasas-dragonfly-will-fly-around-titan-looking-for-origins-signs-of-life