Jupiter's radiation maps are key for new European research

New comprehensive mapping of radiation bombarding the moon of Jupiter - Europe shows where and how deeply scientists should continue their further search for biological activity.

Since the NASA Galileo mission has provided convincing evidence of a global ocean under the ice shell of Europe in the 1990s, scientists believe that the moon is one of the most promising places in our solar system to search for ingredients for the birth of life. There is also a mass of observations of how salt water circulating in the lunar interior, makes its way to the surface.

Studying the information gained in more depth, scientists developing future missions hope to learn more about the possible habitability of the ocean of Europe. However, the surface of Europe is bombarded by the constant and intense radiation of Jupiter. This radiation can destroy or change the samples transported to the surface, which makes it difficult to study the materials further, violates the truth of the representations of conditions in the ocean of Europe.

When planning the upcoming study of Europe, scientists faced many unknowns: where is the radiation most intense? How deep are high energy particles? How radiation affects what is on the surface and below - including potential chemical traits or biosignals, which can mean the presence of life.

A new scientific study, published today in Nature Astronomy, is the most comprehensive simulation and mapping of radiation across Europe and offers key pieces of the puzzle. The lead author is Tom Nordheim, Research Associate, Jet Propulsion Laboratory, NASA, Pasadena, California.

“If we want to understand what is happening on the surface of Europe and how the ocean below reacts to it, we need to understand this radiation,” said Nordheim. “When we study materials extracted from the subsurface layer, what do we end up seeing? Is this what is in the ocean, or a result of what happened to the samples after they were taken to the surface? ”

Using the data from Galileo two decades ago and measurements of the electron flux produced by NASA Voyager 1, Nordheim and his crew considered in more detail the nuances of the radiation falling on the surface of the satellite of Jupiter. They found that radiation doses depend on the location of the location where the measurements were taken. The strongest radiation is concentrated in areas around the equator, and its intensity decreases closer to the poles.


The surface map of Europe shows the areas that receive the highest dose of radiation (pink). US Geological Survey, NASA / JPL-Caltech, Johns Hopkins Applied Physics Laboratory, Nature Astronomy

Revealed severe zones appear as oval-shaped regions that are connected at narrow ends that cover more than half of the moon.

“This is the first prediction of radiation levels at every point on the surface of Europe and is important information for future missions to Europe,” said Chris Paranikas, co-author of the Johns Hopkins Laboratory of Applied Physics in Laurel, Maryland.

Scientists now know where the regions are least affected by radiation, which can be important information for Europa Clipper, headed by JPL, NASA's Jupiter orbit mission and monitoring Europe with about 45 close spans. The spacecraft can start as early as 2022 and will carry cameras, spectrometers, plasma and radar instruments to study the composition of the lunar surface, its ocean and material ejected to the surface.

In his new work, Nordheim did not stop on a two-dimensional map. He went deeper, measuring how far radiation penetrates beneath the surface, and building 3D models of the most intense radiation to Europe. The results tell us how deeply scientists must dig or drill during a potential future landing mission in Europe in order to find any biological traits that can be saved.

Studies show results that vary from 4 to 8 inches (from 10 to 20 centimeters) in areas with the highest radiation - to a depth of less than 0.4 inches (1 centimeter) in European regions at middle and high latitudes to the poles of the moon.

To reach this conclusion, Nordheim experienced the effects of radiation on amino acids, the basic building blocks for proteins, in order to find out how Jupiter’s radiation will affect potential bio-signs. Amino acids are among the simplest molecules that qualify as a potential biological indicator, the newspaper notes.

“The radiation that is bombarding the surface of Europe leaves a kind of fingerprint,” said Kevin Rook, co-author of new research and project specialists for the potential mission of Europa Lander. “If we know what this imprint looks like, we can better understand the nature of any organic matter and possible biosignals that can be detected in future missions, whether they are spacecraft that fly to Europe or land on it.

The mission of the Europa Clipper team studies possible orbit paths, and the proposed routes pass through many regions of Europe that experience lower levels of radiation, Rud said. “This is good news to explore potentially fresh ocean material that has not been greatly altered by the“ fingerprint ”radiation of Jupiter.”

JPL, a Caltech division in Pasadena, California, manages the Europa Clipper mission at NASA's Washington Science Mission.

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