Data from a 20-year-old mission to Jupiter suggests that our next sojourn to the planet could reveal whether one of its icy moons may host life.
In 1997, the Galileo spacecraft buzzed Europa, coming within 250 miles of its icy surface. That was close enough to capture data about any geysers the moon might host, which in turn would give scientists a clue about the habitability of the ocean beneath the ice.
But not all the data the craft gathered made it back to Earth because, early in the mission, one of its antennas didn’t unfurl properly. Still, Xianzhe Jia, an associate professor at the University of Michigan, guessed that there may be clues lurking in the information that was beamed back.
And there were. In data from the magnetometer and plasma wave instruments, Jia and his colleagues found evidence in one of the flybys that Galileo passed through a cloud of charged particles, particles that could be produced by a gusher of salty water.
Here’s Nadia Drake, reporting for National Geographic:
It’s also possible—and perhaps more likely—that any plumes come from a lake or some other reservoir trapped in the ice. But that still means an orbiting spacecraft, like the Europa Clipper mission that’s tentatively scheduled to launch in the early 2020s, could sample a plume and get a glimpse of what lies beneath the moon’s ruddy, crisscrossed rind.
Ever since the Hubble Space Telescope detected Europa’s plumes, scientists have been working under the assumption that the planned Europa Clipper spacecraft could collect more data on their contents. (In fact, one of the scientists who first detected the plumes using Hubble designed Europa Clipper’s ultraviolet sensor that will report back on the geysers.) Though the mission is still years off, we may get a glimpse of Europa’s habitability before too long.