I’ve been thinking I should write something about the recent discovery of geysers from Europa’s subsurface ocean, but Casey Dreier at the Planetary Society blog basically said everything I want to already.
Europa appears to have all the ingredients for life as we know it: liquid water, energy sources, organic molecules. Scientists have known these things since the Galileo mission to Jupiter. But we haven’t gone back to look for life under the ice – because designing and mounting a mission to do so would be a multi-year, expensive effort. It’s much simpler, and less expensive, to think about smaller missions to Mars, which could launch at a cadence of once every couple years. However, the scientific, societal, psychological, educational, inspirational, and public reward of discovering extraterrestrial life certainly would make a multibilliondollar Europa mission worthwhile.
What the new discovery gives us is easy access to Europa’s subsurface material. Perhaps we can sail a probe through these geyser plumes, testing for biological components. Perhaps we can trawl a few space squid while we’re at it. The easy access, while not up to the same level as Mars, certainly makes a Europa mission easier to think about than one that has to drill through a hundred kilometers of ice!