Subterranean oceans on some of the moons of Jupiter and Saturn are the most likely places in the solar system to host extraterrestrial life. Still, until now, it was thought their icy crusts would make confirming anything impossible.
However, a new lab-based study shows that individual ice grains ejected from Europa and Enceladus may contain enough material for instruments to detect signs of life—if it exists.
Crucially, that means NASA’s Europe Clipper missions—which will blast off in October on a six-year journey—may be able to confirm the existence of extraterrestrial life.
Tiny Fraction
“Even a tiny fraction of cellular material could be identified by a mass spectrometer onboard a spacecraft,” said Fabian Klenner, a University of Washington in Seattle postdoctoral researcher in Earth and space sciences and lead author on a paper published today in Science Advances. A mass spectrometer is an instrument that identifies the structure and chemical properties of molecules by converting them into ions, which are then subjected to electric and magnetic fields. “Our results give us more confidence that using upcoming instruments, we will be able to detect lifeforms similar to those on Earth, which we increasingly believe could be present on ocean-bearing moons,” said Klenner.
‘Veiny Eyeball’
Europa is around 1,900 miles/3,100 kilometers in diameter. It has a thin, oxygen-rich atmosphere, a liquid iron core, and a magnetic field. Its icy surface has fractured, making it look like a “veiny eyeball.” Underneath an 11-mile/18-kilometer thick ice crust is a global ocean of water that could harbor simple life forms.
NASA’s Europa Clipper mission is scheduled to launch on October 10 atop a SpaceX Falcon Heavy rocket from Kennedy Space Center in Florida. It will reach the Jupiter system in April 2030. The mission will spend four years studying Europa during at least 32 close flybys.
Europa was photographed from just 219 miles above by NASA’s Juno spacecraft in 2022.
Cellular Material
As preparation for the Europa Clipper mission, the researchers simulated grains of ice striking the spectrometer by sending a thin beam of liquid water into a vacuum, where it disintegrates into droplets, and using a laser beam to excite the droplets. The water contained sphingopyxis alaskensis, a common bacterium in waters off Alaska. The result is that it’s now thought that the spacecraft’s powerful SUrface Dust Analyzer will be able to detect cellular material in one out of hundreds of thousands of ice grains.
The researchers also described how bacterial cells could enter space, with plumes of material thought to escape through cracks in the ice shell.
“It might be easier than we thought to find life, or traces of it, on icy moons,” said Frank Postberg, a professor of planetary sciences at the Freie Universität Berlin and senior author of the paper “If life is present there, of course.”
Moon Missions
Along with NASA’s Europa Clipper, the European Space Agency’s Jupiter ICy moons Explorer (JUICE) mission will soon study Europa. Now on its way to Jupiter, it will arrive in July 2031 to study Europa, Callisto, and Ganymede closely. The JUICE mission plans to orbit Jupiter 67 times.
Another target for astrobiologists is Enceladus, a much smaller moon of Saturn. It has a warm, salty ocean below its icy surface and plumes or geysers that spew that liquid into space. The proposed NASA Enceladus Orbilander mission is expected to launch in October 2038 and arrive in 2050. It would orbit the moon for six months, during which it would sample its plumes, then land to take larger samples for in-situ examination.
Wishing you clear skies and wide eyes.