Signs of life
Say an alien microbe, perfectly preserved in ice, gets scooped up by Europa Clipper as the spacecraft flies past. Would we actually know what hit us?
There are two instruments aboard Europa Clipper that might see something compelling: the SUrface Dust Analyzer (SUDA), which is about the shape and size of a small snare drum, and the MAss Spectrometer for Planetary Exploration (MASPEX), which looks more like a death ray. Both will be able to capture ice grains. As the spacecraft passes Europa at thousands of kilometers per hour, these machines will collect samples, then identify them by measuring the masses of their basic chemical components.
On Earth, researchers have analyzed bacteria and other biological materials with technology that roughly mimics SUDA and MASPEX. They found signs of amino acids, DNA, and other building blocks of life. In one case, scientists predicted that these signals would be noticeable even if only one ten-thousandth of a cell were present within an ice grain.
At Europa, things won’t be as easy, Waite warned. Scientists would have to untangle any true signs of life from other chemicals that could confuse the picture. Some molecules from Europa may look related to life, but could also form without any life around. And the spacecraft itself could trigger false signs of life as it sheds material from its solar panels.
“You won’t know until you get there and try,” Waite added.