So where do we land? NASA/JPL/Ted Stryk

It will take more than six years to get there. But if long-anticipated signs of life are found on Europa, a newly-proposed joint American-European trek to the enigmatic moon of Jupiter will have been worth it.

Called the Joint Europa Mission, the proposal was unveiled on 24 April by Michel Blanc from France’s Research Institute in Astrophysics and Planetology in Toulouse. At the annual European Geosciences Union meeting in Vienna, Austria, Blanc suggested NASA and the European Space Agency could join forces to plan and mount the mission, which could launch in the mid-2020s.

“The whole idea is that if we think exploring Europa for life is important, it should be an international adventure,” Blanc said. “The ultimate goal is to get to the surface and look for biosignatures of life.”


Europa is reckoned to be a potential cauldron for life because an ocean where life could evolve is believed to lurk beneath its icy surface. Discovery of a watery plume emerging from the surface in 2013 created further excitement, and that was reinforced by the recent discovery of hydrogen in similar plumes on Saturn’s moon Enceladus.

Blanc said the Joint Europa Mission would have three major elements. The most important would be planting a lander on the moon’s surface for 35 days to sample and screen material for traces of life, such as biomolecules and metabolites.

Meanwhile, having delivered the lander, an orbiter craft would spend three months taking laser, magnetic and seismic measurements to unravel more about the basic structure of the planet. It would focus on the composition and thickness of the ocean, already reckoned to be briny and rich in magnesium salts following previous observations of seeps to the surface by other space probes flying nearby.

Finally, the orbiter would crash into the moon, but would gather and transmit data on the composition of Europa’s tenuous atmosphere on the way down, identifying any life-related gases such as carbon dioxide and oxygen.

Joining forces

If all proceeds as hoped, the mission would last 6 and a half years. It would take the craft almost five years to reach Jupiter, and further manoeuvres in Jovian orbits to finally reach Europa. It would also need to address two key hazards when designing equipment: the intense radiation around Jupiter and the need to avoid contaminating Europa with stowaway organisms from Earth.

Blanc said the lander would be designed by NASA, and the two agencies would combine forces to build the other components using their respective strengths. NASA already has a mission to Europa under development — officially dubbed Europa Clipper last month — but the orbiter won’t land.

Likewise, the ESA is planning a mission to Ganymede, another of Jupiter’s moons. But the proposal unveiled this week is the first to specifically look for life and put a lander on the surface.

Although the unofficial plan is completely new, it builds on previous NASA proposals to explore Europa, including one earlier this year.

This article has been updated to clarify who presented the mission proposal at the European Geosciences Union meeting.