On Tuesday, NASA released its 2015 budget proposals and requests, and there was a surprise under NASA's Science objectives. 15 million dollars had been set aside for “pre-formulation work for a potential mission to Jupiter's moon, Europa.” The plan is to aim to launch a probe sometime in the 2020s, which would arrive in the Jovian system in the 2030s.
There are ample reasons to dismiss the announcement as another quixotic non-starter from NASA. Jupiter is a radiation factory of epic proportions, and any exploratory spacecraft would have to be tough enough to endure the extreme environment—not to mention that it'd take years to even get there. Close-up Europa missions have been bandied about for decades, but these obstacles have always stopped them short.
Cynicism aside, the tiny fund to get the ball rolling marks the first time a Europa mission has ever been included in a federal budget request. On top of that, Europa's potential for supporting life has made it a popular destination in the public eye, even if the recent film Europa Report predicted some unsavory discoveries (but what space thriller doesn't?). So the more intriguing question is not whether the mission will come to fruition, but how NASA expects to pull it off.
Their leading concept design is the Europa Clipper, an orbital probe designed by the Jet Propulsion Laboratory to take the place of the defunct ESA/NASA collaboration EJSM-Laplace. The Clipper would be put into a very wide rotation around Jupiter to protect it from radiation damage. From there, it would conduct 45 close-up flybys of Europa at varying altitudes—some projected to be as close as 25 kilometers.
Artists depiction of the Clipper fondling Europa with radar. Image: NASA/JPL-Caltech
It may seem sadistically tantalizing to travel all the way to the icy moon without a lander, but the two billion dollar price cap renders ground probes impossible. Interestingly, however, the Clipper may be able to collect valuable samples without ever touching down. The likelihood that fissures on Europa's surface erupt in water geysers is a huge reason this mission is gaining traction in the first place.
If scientists could pinpoint the moon's active geological regions, the Clipper could fly right through one of these plumes like a kid through a sprinkler, collecting liquid samples from deep in the interior. That would be a major step towards unraveling the mystery of the moon's subterranean ocean, especially its potential to support life.
NASA is not the only agency gunning for Europa. Last year, the ESA announced its first large-scale project JUICE (JUpiter ICy moons Explorer), which is slated to launch in 2022 for arrival at the Jovian system in 2030. If they are able to keep their project on track—which is a gargantuan “if”—they will beat NASA to the punch.
But JUICE is a broader mission, and the ESA oddly seems more interested in exploring Callisto and Ganymede than Europa. Similarly, Roscosmos had been developing a Europa lander, but recently switched gears to shoot for Ganymede too. So in an odd twist, it may turn out that the European Union and Russia lock down the two larger Galilean moons, while Europa remains the central goal for NASA.
While space enthusiasts hoping for a pricey Europa lander complete with a drill and a submersible are sure to be disappointed, the net news is good. We are finally making some tangible steps towards the mysterious moon, which is probably packed with space whales. Let's go find out.