Scientists believe that under the icy surface of Jupiter's moon Europa a saltwater ocean exists that may contain more than twice as much liquid water as all of Earth's oceans combined. This artist's concept (not to scale) depicts what Europa's internal structure could look like: an outer shell of ice, perhaps with plumes of material venting from beneath the surface; a deep, global layer of liquid water; and a rocky interior, potentially with hydrothermal vents on the seafloor. The true nature of Europa's inner structure will be examined by NASA's Europa Clipper mission, which is scheduled to arrive at Jupiter in 2030. Europa Clipper's three main science objectives are to determine the thickness of the moon's icy shell and its interactions with the ocean below, to investigate its composition, and to characterize its geology. The mission's detailed exploration of Europa will help scientists better understand the astrobiological potential for habitable worlds beyond our planet. https://photojournal.jpl.nasa.gov/catalog/PIA26438