Jupiter's moon Europa is covered in a thick layer of constantly-shifting ice which appears to be floating atop a deep, warm ocean. Scientists have long suggested that it's the most likely place that life might have evolved beyond Earth. And now, at last, NASA has confirmed our first mission to Europa has entered the development phase.
Today marked the first day of development for the mission, which will be launched in the 2020s. Europa's oceans might be twice as big as Earth's oceans, and scientists speculate that Europa's seas have a rocky floor and even tides created by Saturn's gravitational pull.
John Grunsfeld, associate administrator for NASA's Science Mission Directorate in Washington, said in a release:
Today we're taking an exciting step from concept to mission, in our quest to find signs of life beyond Earth. Observations of Europa have provided us with tantalising clues over the last two decades, and the time has come to seek answers to one of humanity's most profound questions.
So this is explicitly a mission to find life. JPL will be handling the construction of the as-yet-unnamed Europa space vessel, with instruments provided by a variety of labs.
It's worth noting that there's been a longstanding trope in science fiction about how Europa is inhabited and humans shouldn't go there. Perhaps the best known is in the movie 2010, when the aliens say to humanity, "All these worlds are yours except Europa. Attempt no landings there." More recently, there's the indie flick Europa Report, where humans attempt a landing and, well ... you can see the movie if you want to know the rest.
Perhaps in deference to this scifi tradition, NASA's mission will attempt no landing on Jupiter's icy ocean moon. Instead, it will do about 45 flybys, zipping around Jupiter in the process, with instruments that can do everything from visual maps of Europa's surface, to spectral analysis, radar, soundings, magnetic field analysis, temperature sensing, and more.
But even if we don't find life on Europa, there are a few other watery places to explore. Most notably, Jupiter's moon Enceladus is known for spewing vast plumes of water into space, which hint at oceans beneath its crust.