At the end of 2015, Congress gave NASA a big directive: develop a spacecraft that can land on Jupiter’s moon Europa — an icy world that is thought to harbor a saltwater ocean underneath its surface. Because of the likelihood of liquid water on Europa, the moon has become an enticing place of study for researchers and is considered a top candidate in the search for alien life in our Solar System. And now, thanks to the will of Congress, NASA has come up with a mission concept for landing on Europa, as well as the top scientific goals of such a project. The main priority? Figuring out if we’re alone out here.

The main priority? Figuring out if we’re alone out here

Before the Congressional directive, NASA had already been developing a mission that would send a spacecraft to explore Europa. Called the Europa Clipper mission, it envisioned putting a vehicle in orbit around Jupiter. The spacecraft would then periodically fly close to Europa, gather data about the moon, and then fly back out again. However, the mission does not call for the vehicle to actually land on Europa’s surface.

It seemed that such a concept was not ambitious enough for Congress, particularly for one representative John Culberson (R-TX), who has been a driving force behind a mission to the moon, according to Ars Technica. So included in a massive omnibus bill that funded the government for fiscal year 2016, Congress told NASA to develop a Europa orbiter and lander, both of which are meant to launch on the space agency’s future rocket, the Space Launch System, sometime in the 2020s.

After that bill was passed, NASA put together a Science Definition Team, which convened in June to discuss a feasible lander mission and what the top science goals of such a program would be. That team’s report has now been delivered to NASA, and it defines three key goals of a Europa lander, the first of which is seemingly obvious: look for evidence of life. Since liquid water is essential for supporting life on our planet, scientists think that Europa’s subsurface ocean may help support life on the moon as well. Plus, there’s speculation that Europa’s ocean may be twice the size of all the oceans on Earth. This water is also thought to come in contact with a heated rocky seafloor, and the interactions between the liquid and the rock may provide the right amount of energy needed to support microbial life.

The second goal defined in the report is to assess Europa’s habitability. Even if signs of life aren’t found, the lander could determine if it’s even possible for organisms to live on the moon’s surface or subsurface. Finally, the third goal is to figure out if Europa could support future, more ambitious missions. For instance, NASA would like to know if it’s possible for a spacecraft to go deeper inside the icy shell the covers the ocean, or perhaps a vehicle could dip into the water.

The report clarifies that this lander is meant to be separate from the Europa Clipper mission, so it would travel on its own to the moon. The team also lays out the complex way in which the lander will get to Jupiter and then touch down on Europa’s surface. Seeing as how the moon doesn’t have an atmosphere, the lander won’t need a heat shield for protection. The lander also won’t use a parachute to slow itself down, but will instead use a combination of its engine and a sky crane — similar to the one used by NASA’s Curiosity rover — to lower down to Europa’s surface. And the entire process will have to be automated too, given how far Europa is from Earth.

The lander will have a suite of instruments designed to look for life and assess Europa’s habitability

Once on the surface, the lander will have a suite of instruments designed to look for life and assess Europa’s habitability. It’s the first time NASA has developed a life-detection system of this kind since the Viking spacecraft, which the space agency sent to Mars in the 1970s. The Europa lander will include instruments like an Organic Compositional Analyzer, tasked with looking for organic compounds like amino acids, lipids, and more. The vehicle will also be equipped with a microscope, which can look for microbial cells less than 0.2 microns in diameter.

The full details of the instruments and goals of the lander are in NASA’s Europa report. NASA will also be discussing the new lander concept at two upcoming town hall meetings in March and April.

Keeping the Solar System clean to find alien life