flew through the plume of particles that erupts from the south pole of Saturn's small moon Enceladus. Cassini was not designed to look for life, but it does have a simple set of chemical sensors. Those censors showed that while the plume is mostly water vapor, it contains some methane and elemental hydrogen.
published a study that shows the chemistry of the plumes is not in equilibrium. That means there is chemical energy available in Enceladus' subsurface ocean that could sustain life. The authors think the process is similar to what happens at hydrothermal vents in Earth's oceans, which as we know are teaming with all sorts of weird life. Very cool.
But I'm still willing to pay my part of a powerful mission to one of these moons to find out more.