Europa Lander may not have to dig deep to find signs of life

If signs of life exist on the frozen moon of Jupiter Europa, they might not be as hard to find as scientists had thought, reports a new study.

Europa, 3900 kilometers long, is home to a huge ocean under its glacier. shell. In addition, astronomers believe that this water is in contact with the moon's rocky core, making possible a variety of complex and intriguing chemical reactions.

The researchers therefore consider Europa to be one of the best systems of the solar system to shelter extraterrestrial life. Europe is also a geologically active world, so samples of the buried ocean can regularly rise to the surface – for example by localized water upwelling of the ocean and / or by geyser-like degassing, whose evidence has been spotted several times by NASA's Hubble Space Telescope. [Photos: Europa, Mysterious Icy Moon of Jupiter]

NASA aims to hunt such samples in the not too distant future. The agency is developing an overflight mission called Europa Clipper, which is scheduled for launch in the early 2020s. Clipper will be closely studying Europa for dozens of overflights, some of which may be able to zoom in through the plumes suspected of water vapor of the moon. And NASA is also working on a possible post-Clipper landing mission that would look for evidence of life on the surface of Europan or nearby.

It is not known, however, how deep a Europa lander would need to dig for a chance to find something. Indeed, Europa is orbiting Jupiter's radiation belts and is bombarded by charged particles that can transform amino acids and other possible biosignatures into a mosaic

This is where the new study comes in.

The Scientist NASA's Tom Nordheim and his colleagues modeled Europa's radiation environment in detail, how things go wrong from one place to another. combi These results were born from data from laboratory experiments, documenting the speed with which different doses of radiation cut out amino acids (a substitute here for complex biomolecules in general).

The researchers found significant variation, with some Europan locals (equatorial regions) obtaining about 10 times the radiation beat of the others (medium and high latitudes).

At the most favorable places, according to the team, a lander should probably dig only 1 inch (1 inch) into the ice to find recognizable amino acids. In high shooting areas, the depth of the target would be in the range of 4 to 8 inches (10 to 20 cm). (This is not to say that potential European organisms would still be alive at such depths, however, the doses are high enough to cook the hardest microbes in the world, according to the team's members. study.)

says Nordheim, based at the California Institute of Technology and NASA's Jet Propulsion Laboratory, both in Pasadena.

"Even in the harshest radiation zones of Europe, you really have nothing else to do than surface to find material that is not heavily modified or damaged by radiation, "he told Space.com, which is good news for the future landing mission, Nordheim added. Not a limiting factor, planners may feel free to target the areas of Europe most likely to harbor new ocean deposits – the fallout area under a plume – for example – wherever they may be.

Scientists have still not identified such promising contact areas, Europa imagery captured so far has not been clear enough.But the work of Europa Clipper should change things, says Nordheim.

"When we will have the Clipper recognition, the images solved highly it will be a completely different picture, "he said. "This recognition of Clipper is really the key."

The new study was published online today (July 23) in the journal Nature Astronomy.

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