Jupiter's moon Europa is often on the top of lists of "places beyond Earth to look for life," and NASA is planning how to find out what, if anything, is living there. At a briefing at NASA's Washington headquarters today, space agency researchers announced what instruments they want to send to the ice-covered moon to learn more about its surface and what might lurk in the oceans beneath.
The mission is still in the formulation phase, but we have some details on what NASA wants to do: By the 2020s, the agency wants to send a spacecraft on a three year mission to do 45 flybys over Europa, ranging from 16 miles to 1,700 miles above the moon's surface. At the briefing, researchers laid out nine instruments that they want to have aboard the spacecraft in order to, if not prove that life has found a way on Europa, at least understand the mysterious moon better.
NASA scientist Curt Niebur said the agency's Galileo spacecraft passed over the moon 11 times, producing the mosaic 12 images seen above. That isn't much, as Niebur explained, leaving us with only about 10 percent of the surface photographed at a resolution of 200 meters or better.
So naturally the mission to Europa is going to include cameras that will take high-resolution images—with resolution four-times higher than Galileo's—of 90 percent of the moon's surface. "If we've seen amazing things looking at only 10 percent of the surface," Niebur said, "it's hard to even imagine the amazing things we're going to see when we look at even more of the surface at even better resolution."
The spacecraft will also carry a mass spectrometer that will determine the composition of Europa's surface, and hopefully discover what makes up the brown gunk—this is what the researchers call it—that fills in the cracks on Europa's surface.
But the surface, as cool as it is, is only the beginning. Below an estimated 10 kilometers of ice, evidence suggests Europa is home to an ocean that could be another 100 kilometers deep. At the bottom there could be hydrothermal vents, like those on the floor of Earth's oceans, which John Grunsfeld, associate administrator for NASA's Science Mission Directorate, pointed out are "teaming with life."
While a crowd-researched mission to Europa wants to drill below the surface to look around, and NASA scientists mentioned this as a possibility further down the road, the first fly-bys of Europa are going gaze below the ice from up above. Doing so will require the trio of an ice-penetrating radar, a magnetometer, and a plasma instrument, which together will function like an MRI to measure and look through the ice deep down into Europa.
The other instruments will be used to hunt for and analyze plumes that shoot up from Europa's surface, which could carry information on how active the planet is and what its oceans are made of.
The researchers explained that the questions of whether or not Europa could support life and whether or not it is supporting life are actually a series of smaller questions: How deep and salty is Europa's ocean? How thick is the ice shelf? How active is the ice shelf? What is that brown stuff, anyway? And what are those plumes and what's in them?
"If there's life in the solar system and in particular on Europa then it must be everywhere in our galaxy," said Jim Green, the director of NASA's planetary science division. "Understanding these questions are very important because they have major implications to our understanding of our place in the solar system and universe."
The answers to these questions, or the beginning of many more questions, lie just 390 million miles and a decade away.