Europa

Astrobiologists looking for life in the solar system have generally agreed on a shortlist: Mars, Europa, Titan, and possibly Enceladus or other moons. We're in the middle of a golden age of robotic exploration of Mars, but what's next? Based on proximity and scientific promise, the answer appears to be Europa, one of Jupiter's moons. There is now consensus that the moon is covered by an icy layer which overlays an ocean of liquid water. Liquid water is one of the crucial requirements of life, and if nutrients exist in sufficient quantities, there could be life on Europa. The ice layer limits our view and remote sensing capabilities, so a robotic probe that is able to drill through the ice into the ocean is a crucial capability. This article highlights the efforts to make a Europa mission a reality. Mars should certainly remain an important destination for spacecraft, but we also must continue to push the boundaries, and Europa is a scientifically-relevant place to do so.