As technology advances, the question of extraterrestrial life persists. The Milky Way's vast celestial bodies prompt scientists to seek water, energy, and organics. Enceladus, Saturn's moon, appears promising as an 'ocean world.'
As per NASA, Cassini's 20-year mission unveiled ice plumes at 800 mph, offering chances to study Enceladus' potential habitability. A recent concern arose: would the plumes' speed degrade organic compounds in collected samples?
Amino Acids Survive Enceladus' Ice Plumes
Researchers from the University of California San Diego have addressed a crucial unknown regarding the potential degradation of organic compounds within ice grains transported by Saturn's moon Enceladus' plumes.
In a groundbreaking study, titled "Detection of intact amino acids with a hypervelocity ice grain impact mass spectrometer" published in The Proceedings of the National Academy of Sciences (PNAS), the team led by Professor Robert Continetti demonstrated that amino acids in these ice plumes can withstand impact speeds of up to 4.2 km/s.
Their unique aerosol impact spectrometer, constructed in 2012, allowed for precise examination of single particles' collision dynamics at high velocities, revealing the resilience of amino acids to impact velocities.
The experiment involved creating ice grains through electrospray ionization, a process generating charged water droplets that freeze in a vacuum. By measuring mass and charge and employing image charge detectors in the spectrometer, the researchers observed the behavior of these ice grains.
The inclusion of a microchannel plate ion detector enabled precise timing of impact moments down to the nanosecond. The results indicated that amino acids, considered life's building blocks, can be detected with minimal fragmentation at impact velocities of 4.2 km/s, supporting the potential for their detection during spacecraft sampling.
Beyond the implications for the search for extraterrestrial life, Continetti's research raises intriguing questions in chemistry, particularly regarding the impact of salt on amino acid detectability. Enceladus is believed to harbor vast salty oceans, potentially influencing the clustering of molecules on ice grain surfaces and enhancing their detectability.
The study not only holds promise for discovering life in the solar system but also contributes to fundamental chemistry inquiries, echoing the pioneering work of UC San Diego's founding faculty in exploring the formation of life's building blocks through ice grain impact-induced chemical reactions.
Lessons From Cassini Can Help in Europa Clipper's Mission
NASA plans to launch the Europa Clipper by 2024 to explore Jupiter and its moon, Europa, another ocean world with an icy composition similar to Enceladus. Similar to Enceladus, Europa is believed to have an ocean beneath its icy surface, potentially evidenced by observed geysers, although the source and safety for probes remain uncertain.
Researchers, learning from Cassini's geyser passes on Enceladus, anticipate Europa Clipper's spectrometer may face similar challenges, prompting design modifications.
To detect life-supporting conditions, Cassini's team improvised during Enceladus missions, as the spectrometer wasn't designed for geyser sampling. Europa Clipper's spectrometer is undergoing design changes, excluding reactive titanium in favor of a composite, likely ceramics.
Scientists view geysers as shortcuts in the search for life in Europa and Enceladus' subsurface oceans, vital as funding uncertainties surround proposed missions to explore outer planets' "ocean worlds."
As NASA's Jet Propulsion Laboratory navigates budget constraints, scientists see potential confirmation of geysers on Europa as an attractive site for a lander mission, even as funding for a proposed Europa lander remains uncertain in the 2018 budget proposal.
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