Jupiter’s icy moon Europa has long been a tempting fruit for astrobiologists looking for life beyond Earth. Planetary scientist and WSF alum Steven Squyres calls it “the most fascinating place in the solar system.” And for good reason. Science has amassed powerful evidence indicating that beneath the moon’s thick, icy crust stirs a vast ocean of liquid water, possibly teeming with alien microbes fed by hydrothermal vents.

Now a team of researchers led by Murthy Gudipati of the Jet Propulsion Laboratory at the California Institute has taken a bold step toward a lander mission by determining just how much ice and water is required to guard life against the deadly blasts of radiation that bathe Europa with every rotation. Astrobiology Magazine reports on the team’s technique:

Gudipati and his team placed organic detector molecules behind ice of varying thickness, then fired an electron gun at them. They measured not only how deeply the electrons themselves traveled, but also the penetration of the photons knocked loose by the electrons—a secondary effect that other experiments did not track.

“Those photons can penetrate far deeper and cause damage to organic matter,” Gudipati said.

The result of Gudipati’s experiments will give future missions planners a better idea of where and how to drill on Europa’s surface for signs of life. Squyres, for one, is eager to get started. Watch as he describes his dream mission to the icy moon.