Rod Pyle
A diver tests BRUIE in a water tank at the Aquarium of the Pacific in Long Beach, California Credit: NASA/JPL-Caltech
Over the past 60 years, NASA has explored the solar system from the sun to the Kuiper belt. While many of these missions, especially those beyond Saturn, have been oneshot flybys (such as the Voyagers and recently New Horizons), others have charted many of the moons of Jupiter and Saturn extensively by repeated orbital passes. The sole landing on these icy worlds was the Huygens probe, which parachuted to the surface of Saturn’s moon Titan in early 2005 as part of NASA’s Cassini mission, and which operated for about 90 minutes after touchdown.
The data gathered from a few of these moons has provided compelling evidence of possible warm oceans beneath their frozen surfaces, Saturn’s Enceladus and Jupiter’s Europa in particular. NASA would like to explore these subsurface seas, as they appear to offer promise for the potential of life. Between their internal geological activity, spurred by the tortuous gravitational complexities of Jupiter and Saturn’s many moons that heat these cold worlds, and the watery plumes spouting from both, they are very compelling to planetary scientists (especially exobiologists). There are a variety of missions under consideration for these moons, the most immediate of which is the Europa Clipper, currently slated for launch in 2025. But this mission, to be managed by NASA’s Jet Propulsion Laboratory (JPL) and Johns Hopkins University, is another orbiter and will not be sporting a lander.