ESA sets Cosmic Vision sights on Jupiter's icy moons

In its "Cosmic Vision" push to explore the Solar system, Europe has set its sights on Jupiter icy moons, with a mission to launch for Europa, Ganymede and Callisto in 2022.

The so-called JUICE mission - Jupiter Icy moons Explorer - will arrive at Jupiter in 2030 and spend at least three years making detailed observations. Europa, Ganymede and Callisto are all thought to host internal oceans, so the mission will study the moons as potential habitats for life, addressing two key themes of Cosmic Vision: what are the conditions for planet formation and the emergence of life, and how does the Solar System work?

JUICE will continuously observe Jupiter's atmosphere and magnetosphere, and the interaction of the Galilean moons with the gas giant planet.

It will visit Callisto, the most heavily cratered object in the Solar System, and will twice fly by Europa. JUICE will make the first measurements of the thickness of Europa's icy crust and will identify candidate sites for future in situ exploration.

The spacecraft will finally enter orbit around Ganymede in 2032, where it will study the icy surface and internal structure of the moon, including its subsurface ocean.

Ganymede is the only moon in the Solar System known to generate its own magnetic field, and JUICE will observe the unique magnetic and plasma interactions with Jupiter's magnetosphere in detail.

"Jupiter is the archetype for the giant planets of the Solar System and for many giant planets being found around other stars," says Alvaro Giménez Cañete, ESA's director of science and robotic exploration. "JUICE will give us better insight into how gas giants and their orbiting worlds form, and their potential for hosting life."

JUICE was chosen over two alternatives: NGO, the New Gravitational wave Observatory, to hunt for gravitational waves, and ATHENA, the Advanced Telescope for High-Energy Astrophysics. Either of these may be reconsidered when ESA again polls the scientific community in another call for large missions, expected in 2013.

ESA's next big Solar System venture is the BepiColombo mission to put two orbiters around Mercury from 2022, following a launch in 2014. That mission will just the third to the planet closest to the Sun, after NASA's Mariner 10, which made fly-bys in 1974-75, and Messenger, which has been in orbit around Mercury since March 2011.

And, in 2016 and 2018 ESA is planning a pair of launches to Mars. The ExoMars missions will test a descent module and then land a rover equipped to test geological samples gathered by deep drilling.