Exploration of Jupiter’s moon Europa and other solar system worlds that are known or suspected to have subsurface oceans was discussed in two separate presentations at a recent NASA conference on the future of space exploration.
Titled the “Planetary Science Vision 2050 workshop,” and held from February 27-March 1 in Washington, DC, the conference consisted of numerous discussions, panels, and proposals, including an emphasis on ocean worlds, the top contenders for life beyond Earth.
Europa, for which the earliest evidence of a subsurface ocean came from NASA’s 1970s Voyager probes, was the focus of a presentation by Kevin Peter Hand, Deputy Chief Scientist for solar system exploration at NASA’s Jet Propulsion Laboratory (JPL) in California.
Hand discussed the findings of a pre-Phase A study he headed evaluating the benefits of a future Europa lander mission and the design of the potential lander.
He outlined the purposes of such a mission as searching for biosignatures in Europa’s surface and subsurface material, determining the composition of non-ice material near the surface and the proximity of liquid water, and characterizing Europa’s surface and subsurface properties as well as the processes that created them.
“Were biosignatures to be found in the surface material, direct access to, and exploration of, Europa’s ocean and liquid environments would be a high priority goal for the astrobiological investigation of our solar system. Europa’s ocean would harbor the potential for the study of an extant ecosystem, likely representing a second, independent origin of life in our solar system,” Hand emphasized.
If a lander detects signs of life, there will be follow-up missions likely consisting of robotic submarines.
Led by Amanda Hendrix of the Planetary Science Institute in Tucson, Arizona, and Terry Hurford of NASA’s Science and Exploration Directorate, co-chairs of NASA’s “Roadmaps to Ocean Worlds” team, the second presentation discussed possible missions to the increasing number of solar system ocean worlds.
Their report defined ocean worlds as those harboring a liquid ocean, regardless of whether that ocean is global. Earth is the first known ocean world and serves as a reference point for understanding the others.
In addition to Europa, ocean worlds include Jupiter’s moons Ganymede and Callisto, and Saturn’s moons Enceladus and Titan, all known to harbor underground oceans.
Recent evidence for the presence of organic materials and pre-biotic chemistry on these worlds make them top destinations for missions aimed at finding signs of life.
Saturn’s moon Dione, the dwarf planet Ceres, Neptune’s moon Triton, and dwarf planet Pluto are considered candidate ocean worlds, as indirect evidence suggests they too have underground oceans.
Goals regarding ocean worlds consist of identifying them, determining the nature of the oceans, finding out whether they have the energy and chemistry to support life, and figuring out how life might exist within them.