An artist’s rendition of Saturn’s moon Enceladus depicts hydrothermal activity on the seafloor and cracks in the moon’s icy crust that allow material from the watery interior to be ejected into space. Credit: NASA/JPL-Caltech
Key points:
- Ice-encrusted oceans of Saturn and Jupiter’s moons emanate plumes of ice grains that may contain extraterrestrial life.
- Researchers confirmed instruments that will be used in future missions to these moons can detect cellular material in as little as one ice grain.
- The instrument SUrface Dust Analyzer was sensitive enough to detect Sphinogopyxis alaskensis bacterium and negatively charged ions within the ice grain.
The ice-encrusted oceans of the moons of Saturn and Jupiter are a leading candidate in the search for extraterrestrial life. In a new study, published in Science Advances, researchers show that individual ice grains ejected from these planetary bodies contain sufficient material for instruments to detect signs of life.
A previous mission to Saturn’s moon Enceladus discovered cracks that emanate plumes containing gas and ice grains. An upcoming mission to Jupiter’s moon Europa will take a similar approach and researchers designed instruments to better assess these grains for signs of life.
The research team employed an experimental setup that sends a thin beam of liquid water into a vacuum where it disintegrates into droplets and then used a laser beam to excite the droplets. Next, the researchers used mass spectral analysis on the droplets to mimic what instruments on the space probe will detect.
Their instruments, including the SUrface Dust Analyzer that will be used on future missions, can detect cellular material in as little as one ice grain. In fact, they were able to detect the Sphingopyxis alaskensis bacterium in a single ice grain. This result underscores the success of analyzing single ice grains for biomaterial rather than averaging across billions of individual grains. The instrument is also sensitive enough to detect ions with negative charges, which will help researchers accurately detect fatty acids and lipids.
“With suitable instrumentation, such as the SUrface Dust Analyzer on NASA’s Europa Clipper space probe, it might be easier than we thought to find life, or traces of it, on icy moons,” said senior author Frank Postberg, professor at Freie Universität Berlin. “If life is present there, of course, and cares to be enclosed in ice grains originating from an environment such as subsurface water reservoir.”