JPL, home to three thousand engineers and five hundred scientists, is very old—2016 is its eightieth anniversary—but it's only in the last few years that the close of the space shuttle program has left enough of an excitement gap for the center's singular brilliance to shine through. In contrast to NASA's other outposts, where you'll find a lot of unflappable pilot types with high-and tight haircuts, JPL is full of strange, excitable, idea people. Climate scientists who work side gigs as comedians and engineers who shave star shapes into their Mohawks before landings. ... Just off California Interstate 210, there are two signs on the side of the road. The bottom one shows an outline of the California mule deer that tend to meander out of the sagebrush and into passing traffic. The top one just says "Space," with an arrow pointing forward. The second sign is not an official JPL sign. No one really knows where it came from. People around here presume it was put there as a joke and no one ever bothered to take it down. ... Even though JPL is currently beholden to its parent organization's budgets and approvals, it is actually the reason NASA exists. ... The best way to understand what JPL does is to consider the center's "directorates," which is space-agency-speak for departments. Among these are four organized by planet. Taken together, they sound like a particularly difficult round of Jeopardy: Earth Science, Astrophysics, Mars, and Planets That Are Not Mars.

Europa truly does represent a singular chance. Crossing 800 million kilometers with a sizable, robust payload will require vast sums of money—there won’t be a second chance. But Europa represents a gamble in another sense, too. No one knows whether NASA will discover a frozen, dead world far from the Sun or if the organization will make the most profound of discoveries just below the ice. ... During the last decade, NASA has recast its human and robotic space exploration programs around the search for life both in our Solar System and beyond. Much of this effort has focused on Mars, which is relatively close to Earth and may have harbored life in the past. Culberson has pushed the agency further to seek extant life. He and a lot of scientists believe the best place to find extraterrestrial life in the Solar System lies in deep oceans below Europa’s inhospitable surface. ... Notably, the JPL team thinks it has solved the vexing problem of planetary protection, the concern that any stray microbes from Earth could contaminate Europa’s ecosystem. The solution has come straight out of the pages of science fiction—the lander mission will be the first interplanetary spacecraft to carry a self-destruct mechanism.