2.) Enceladus. Saturn’s icy moon is smaller and has far less water than Europa, but it announces its liquid ocean (beneath a surface of solid ice) uniquely: by spewing 300-mile plumes of water into space! These geysers let us know for certain that there’s liquid water, and in tandem with the other elements and molecules necessary for life, such as methane, ammonia and carbon dioxide, there just might be life beneath the oceans of this world, too. Europa has more heat, more water and hence — we think — a greater chance, but don’t count Enceladus out, since it has a thinner ice surface and erupts far more spectacularly, meaning that we could find life with an orbiting mission, rather than having to drill down beneath the surface!
Would we even need an orbital mission for this? Assuming microbial life is distributed around Enceladus’s watery interior, and not isolated in one or more pockets, and assuming the geysers happen at different parts of the surface, isn’t it likely evidence of microbial life, if not microbes, themselves, would be ejected in these eruptions? Spectroscopic analysis of the geysers should let us know if there is life present in the water getting spewed out. An orbital mission could confirm it if there is any question about the observational data.
It seems like all this will take is a government interested in funding science and education. That should be easy enough, right?