By 
NASA/JPL-CALTECH
The ice-encrusted oceans of some of the moons revolving around Saturn and Jupiter are directing candidates seeking for extraterrestrial life. A new lab-based research conducted by the University of Washington in Seattle and the Freie Universität Berlin reveals that single ice grains emitted from these planetary bodies may have sufficient material for instruments headed there in the fall to find signs of life, if such life exists.
“For the very first time we have revealed that even a small fraction of cellular material could be recognized by a mass spectrometer onboard a spacecraft,” said chief author Fabian Klenner, a UW postdoctoral scientists in Earth and space sciences. “Our consequences provide us more belief that using upcoming instruments, we will be capable to detect lifeforms likely to those on Earth, which we progressively think could be present on ocean-bearing moons.”
The open-access study was published in Science Advances. Other authors in the international group are from The Open University in the U.K.; NASA’s Jet Propulsion Laboratory; the University of Colorado, Boulder; and the University of Leipzig.
The Cassini mission that completed in 2017 detected parallel cracks near the south pole of Saturn’s moon Enceladus. Emerging from these cracks are plumes which contains gas and ice grains. NASA’s Europa Clipper mission, set to launch in the month of October, will convey more instruments to figure out in even more deep way an icy moon of Jupiter, Europa.
To get ready for that mission, scientists are examining what this new generation of instruments might detect. It is technically restrictive to directly simulate grains of ice flying through space at 4 to 6 kilometers per second to reach an observational instrument, as the real collision velocity will be.
Instead, the authors used an experimental setup that convey a narrow beam of liquid water into a vacuum, where it fall apart into droplets. They then used a laser beam to move the droplets and mass spectral analysis to mimic what instruments on the space investigation will find.
Latest consequences reveals that instruments slated to go on missions in the future, like the SUrface Dust Analyzer onboard Europa Clipper, can spot cellular material in one out of hundreds of thousands of ice grains.
The research concentrated on Sphingopyxis alaskensis, a usual bacterium in waters off Alaska. While several studies use the bacterium Escherichia coli as a model organism, this single-celled organism is much tinier, survives in cold atmosphere, and can live with few nutrients. All these things converts it into a better candidate for potential life on the icy moons of Saturn or Jupiter.
“They are very tiny, so they are in theory able to be fitting into ice grains that are ejected from an ocean world like Enceladus or Europa,” Klenner said.
(NASA / JPL-Caltech Illustration)
Consequences show that the instruments can find this bacterium, or portions of it, in a individual ice grain. Separate molecules end up in different ice grains. The latest study reveals that examining single ice grains, where biomaterial may be focused, is more successful than averaging across a bigger sample consists of billions of single grains.
A previous research conducted by the same scientists revealed proof of phosphate on Enceladus. This planetary body now looks to contain energy, water, phosphate, other salts and carbon-based organic material, forming it progressively likely to support lifeforms similar to those found on Earth.
“For me, it is even more interesting to look for lipids, or for fatty acids, than to look for building blocks of DNA, and the cause is because fatty acids seems to be more stable,” Klenner said.
“With suitable instrumentation, like the SUrface Dust Analyzer on NASA’s Europa Clipper space probe, it might be simple than we thought to detect life, or traces of it, on icy moons,” said senior author Frank Postberg, a professor of planetary sciences at the Freie Universität Berlin.
“If life exist there, no doubt, and cares to be enclosed in ice grains generating from an environment like a subsurface water reservoir.”
