How Could We Detect Life in Europa’s Geysers?

Scientists consider how to sample the spray from Jupiter’s moon.

Europa plumes art.jpg
Artist's concept of a water vapor plume on Europa.

The NASA Astrobiology Institute (NAI) and the Solar System Exploration Research Virtual Institute (SSERVI) will co-host a workshop next week at NASA’s Ames Research Center in California to discuss the potential for finding life in the watery plumes spraying up from Jupiter’s moon Europa. The plumes were discovered more than a year ago, and since then these potential windows to the moon’s subsurface have become a principal focus in the search for life beyond Earth.

Europa is thought to be covered by an ice crust several miles thick. In some spots, like the areas of so-called “chaotic terrain,” the crust is so cracked that water seems to be spouting out due to tidal stresses.  Speculation began decades ago, when the Galileo spacecraft toured the Jovian system, that the subsurface ocean might be habitable. In fact, Europa may be the only body in the Solar System that has a chance of hosting life more complex than just microbes.

Scientists at the workshop, which is scheduled for February 18, will hone in on that possibility and the idea of analyzing water samples from the plume, searching for chemical clues as to whether the subsurface ocean is habitable or even contains microbial cells today. The first question is what measurements would be needed to detect and characterize life in an acquired water sample, and what instruments could take these measurements. Do the instruments exist already, or would they have to be developed? Other issues up for discussion are how the water samples could best be collected and whether they’d have to be specially prepared for analysis.

One possibility for sampling the plumes is to use cubesat(s) deployed from a larger Europa-bound spacecraft. The greatest challenge for any Europa mission, however, will be to withstand Jupiter’s extreme radiation field. Radiation would rapidly change the chemical (and biological, if any) content of a water sample, so collecting water from a Europan plume will be a tricky proposition.

The one-day meeting will be webcast live at https://ac.arc.nasa.gov/europa.

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