New research shows that life could survive on Europe's surface, but how could it have gotten there?
While scientists throughout Europe have been thinking about an underground ocean since NASA's Twin Voyager probes passed Jupiter in 1979, recent research has shown that the ocean can actually shoot up to the surface of Europe.
The ice moon is littered with cracks and tears, and observations from the Hubble Space Telescope and the Galileo Mission have shown that some of these cracks have separated. Dark, icy material seemed to flow into the opened gaps. In 201
Kevin Hand of NASA's Jet Propulsion Laboratory, who also took part in the research, has been studying Europe for a long time. In a paper written in 2013 with Planetary Science co-author Mike Brown, Hand came to the conclusion that the surface of Europe could "taste" like ocean water here on earth – enriched with salts like magnesium sulphates. If a chemical exchange takes place between the ocean and the surface, this would lead to a rich chemical environment.
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Another way to introduce life-support materials into Europe's icy surface is a process called meteorite gardening or gardening implications.
"The basic idea is that in an airless world like Europe or the Moon, small meteors mingle and shake the surface, much like a garden," said Cynthia Phillips of NASA's Jet Propulsion Laboratory, who was not involved with the recent research, but was very active in studying Europe.
Over time, according to Phillips, a random distribution of small and large impacts takes place, and different amounts of different material are mixed. While impact gardening definitely takes place in Europe, she added that scientists do not have a good measurement of the frequency of impact and therefore can not say with certainty how deep the surface material layer might be.
Meteorite impacts over a period of 10 million years would expose and mix materials from shallower depths exposed to more intense irradiation with material from greater depths exposed to less radiation, thereby reducing the effect of ice protection.
But the ice and minus 300 degrees Fahrenheit on the surface of Europe provide a protective shield. Laboratory studies conducted by Nordheim and colleagues have found that amino acids contained in water ice at low temperatures, according to their work, have "significantly lower destruction rates."
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The only way to be sure about Europe's potential life is to go there – and NASA is planning just that.  The Europa Clipper mission is an orbiter expected to be operational by mid-2020. The spacecraft would make a series of fly-bys from Europe. With a series of instruments, the mission aims to confirm the presence of the sub-surface ocean, to characterize its composition, and to study the processes of surface ice-ocean exchange. And NASA is also studying concepts for a Europa-Lander mission that would launch to Europe Clipper.
Phillips said that a concept presented by her and a group of colleagues includes instruments such as an organic chemistry analyzer, a vibration spectrometer, a microscope, a camera, and a seismic analyzer.
"Tools like these that work together," Phillips said, "should be able to provide multiple proofs as to whether biosignatures can be found directly beneath Europe's surface."