A key problem, though, is that we have no way of directly detecting life on another world. There just simply isn’t an instrument that exists that can tell you definitively if life is there or not. So instead, the lander would put together nine lines of evidence for biosignatures.
One of these would be the Microscope for Life Detection (MLD) instrument, which could find microbial cells as small as 0.2 microns in diameter, roughly the size of small bacteria on Earth. Other instruments would look for cell-like structures and work out if samples came from the ocean.
A seismic instrument, meanwhile, would measure the thickness of Europa’s ice shell and the thickness of its ocean, through “acoustic monitoring of cracking events in the ice shell.”
To keep the instruments safe from Jupiter’s radiation, weighing a total of 42.5 kilograms (93.7 pounds), they would be kept inside a vault. The only instrument not in the vault would be the Context Remote Sensing Instrument (CRSI), which would take images on the surface.
Of course, the detection of life is not a guarantee, but the scientific return of the mission would still be vast. Not least, it would tell us if Europa is a potentially habitable world, and lay the groundwork for a possible future robotic mission to explore beneath the icy surface.
“This mission would significantly advance our understanding of Europa as an ocean world, even in the absence of any definitive signs of life, and would provide the foundation for the future robotic exploration of Europa,” the report says.
“These measurements would then feed forward into designs of future robotic vehicles that would explore across the surface, or down into the subsurface.”
This would be the first direct search for life on another world since the Viking landers touched down on Mars in the 1970s. There’s no guarantee it would go ahead yet; this is merely a look at how feasible such a mission would be. NASA said it would now be “engaging the broader science community to open a discussion about [the report’s] findings.”
But there’s little doubt there is huge interest in sending a lander to Europa. In our search for life beyond Earth, this icy moon of Jupiter might be one of our best bets.