NASA is setting its sights on getting a much closer, deeper look at Jupiter's tantalizing moon, Europa, and the mysterious ocean hidden beneath its icy crust. With two orbital missions already in the works, by NASA and the European Space Agency, NASA is looking further into the future toward a possible mission to put a robot on the surface.
Europa's ocean, which may lie under only a few miles of ice—perhaps only a few hundred feet in some places—may be as deep as 30 miles, and contains more water than in all of Earth's oceans. With the possibility of some form of hydrothermal vents supplying heat and life-supporting chemicals on the ocean's floor, like those on Earth, the tiny moon has become one of the hottest subjects in the search for extraterrestrial life in the solar system.
In advance of issuing a call for formal proposals, NASA is priming the scientific community to begin thinking about what set of scientific instruments should be included on a lander. Ultimately, ten proposals will be selected to proceed to a competitive concept study, which carries funding of $1.5 million for each selected group, who will have a year to submit their technical proposals.
Past spacecraft, including NASA's Voyager and Galileo, gathered the first evidence leading to the discovery of Europa's ocean: patterns in the cracks of the moon's icy crust interpreted as ice sheets floating on water, as well as disturbances in Jupiter's magnetic field in Europa's vicinity that can be explained by the presence of a salty ocean.
Most recently, the Hubble Space Telescope detected plumes of water vapor erupting from Europa's surface, further wetting scientists' appetites to explore the liquid realm beneath.