Almost a billion miles away, it rains rocket fuel on Titan—Huygens landed there in 2005 as Cassini’s 127 flybys mapped methane rivers and Kraken Mare, a sea bigger than the Caspian. Next up: NASA’s Dragonfly, a nuclear-powered drone launching in the late 2020s, will fly this Saturn moon’s thick air to probe organic dunes, sample methane lakes, and hunt for life above a hidden ocean.