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Ready to detect life on ocean-bearing moons with upcoming space missions

Fly past Saturn's moon Enceladus

Fly past Saturn's moon Enceladus
Image Credit: Illustration @ NASA/JPL

News from Jun 16, 2020

Identifying and distinguishing between abiotic and biotic signatures of amino acids, fatty acids, and peptides in ice grains emitted by ocean-bearing moons, such as Jupiter’s moon Europa or Saturn’s cryovolvanically active moon Enceladus, is key to the search for life on these worlds. An international team led by Fabian Klenner and Prof. Frank Postberg from the Planetary Sciences research group at Freie Universität Berlin have performed laboratory analogue experiments to simulate accurately the impacts of ice grains containing biologically relevant organic molecules onto spaceborne mass spectrometers. These have shown that it is possible to clearly identify amino acids, fatty acids, and peptides in ice grains detected in space, even at very low concentrations (less than 100 molecules per ice grain).          


The team also investigated the behavior of these biomolecules in a realistic ocean world scenario, in which numerous background compounds would be in the ice grains. They demonstrated that suitable space instruments could clearly determine if the organic molecules were formed by abiotic or biotic processes. The researchers inferred that such space instruments will be most sensitive to organic biosignatures at encounter velocities of 3-8 km/s, with the ice grain protecting the molecules at these hypervelocity impact speeds. The results are one important piece of the puzzle in detecting life beyond Earth in the near future. The next space mission exploring the habitability of the ocean moon Europa will be NASA’s Europa Clipper, in which the Planetary Sciences research group of Freie Universität is participating.

The results were published in two articles in the research Journal Astrobiology in Februar and June 2020.

The picture shows the Artist’s impression of the Cassini spacecraft flying past Enceladus and its gas/ice vapor plume

Biologically important molecules potentially emitted in plume ice grains would be detected on Enceladus and other ocean worlds, even at very low concentrations, clearly showing if the organic molecules were formed abiotically or biotically.

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