This problem is far from hypothetical. In April, the European Space Agency's Juice spacecraft blasted off from French Guiana on a course to Jupiter and its moons. One of those moons, Europa, has a deep, briny ocean beneath its frozen crust and is among the most promising places in the solar system to look for alien life. Next year, NASA's Europa Clipper spacecraft will launch, also aiming for Europa. Both spacecraft have onboard instruments that will look for the fingerprints of complex organic molecules ?" a possible hint of life beneath the ice. And in 2027, NASA plans to launch a dronelike helicopter called Dragonfly to buzz over the surface of Saturn's moon Titan, a hazy, carbon-rich world with liquid hydrocarbon lakes that might be just right for hosting life ?" but not as we know it.