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takyon [soylentnews.org] writes:

Europa Lander May Not Have to Dig Deep to Find Signs of Life [space.com]

If signs of life exist on Jupiter's icy moon Europa, they might not be as hard to find as scientists had thought, a new study reports. [...] NASA aims to hunt for such samples in the not-too-distant future. The agency is developing a flyby mission called Europa Clipper, which is scheduled to launch in the early 2020s. Clipper will study Europa up close during dozens of flybys, some of which might be able to zoom through the moon's suspected water-vapor plumes [space.com]. And NASA is also working on a possible post-Clipper lander mission that would search for evidence of life at or near the Europan surface.

It's unclear, however, just how deep a Europa lander [space.com] would need to dig to have a chance of finding anything. That's because Europa orbits within Jupiter's radiation belts and is bombarded by fast-moving charged particles, which can turn amino acids and other possible biosignatures into mush.

That's where the new study comes in. NASA scientist Tom Nordheim and his colleagues modeled Europa's radiation environment in detail, laying out just how bad things get from place to place. They then combined these results with data from laboratory experiments documenting how quickly various radiation doses carve up amino acids (a stand-in here for complex biomolecules in general).

The researchers found significant variation, with some Europan locales (equatorial regions) getting about 10 times the radiation pounding of others (middle and high latitudes). At the most benign spots, the team determined, a lander would likely have to dig just 0.4 inches (1 centimeter) or so into the ice to find recognizable amino acids. In the high-blast zones, the target depth would be on the order of 4 to 8 inches (10 to 20 cm). (This is not to imply that potential Europan organisms would still be alive at such depths, however; doses there are high enough to cook even the hardiest Earth microbes, study team members said.)

Also at Motherboard [vice.com] and Gizmodo [gizmodo.com].

Preservation of potential biosignatures in the shallow subsurface of Europa [nature.com] (DOI: 10.1038/s41550-018-0499-8) (DX [doi.org])

Biosignature hide and seek [nature.com] (DOI: 10.1038/s41550-018-0542-9) (DX [doi.org])

Related: Science Instruments Selected for NASA's Europa Mission [soylentnews.org]
NASA Releases Europa Lander Study 2016 Report [soylentnews.org]
Could a Dedicated Mission to Enceladus Detect Microbial Life There? [soylentnews.org]
Plate Tectonics on Europa and Subsurface Oceans in the Outer Solar System [soylentnews.org]
Europa Landers Could be in Danger of Sinking Into a Porous Surface [soylentnews.org]
NASA Finds Evidence of Water Plume on Europa [soylentnews.org]
Complex Organic Molecules Found on Enceladus [soylentnews.org]

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