Nuclear-Powered ‘Tunnelbot’ to Search For Life on Jupiter’s Moon Europa

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One of the most promising spots to find life in the solar system beyond Earth is Europa, Jupiter’s fourth-smallest moon.

But even though scientists suspect the moon’s liquid ocean might harbor living organisms, it’s protected by a solid layer of ice that could be as much as 30 kilometers (18 miles) deep. Between 1995 and 2003, NASA’s Galileo spacecraft made several flybys of Jupiter’s moon, Europa.

Researchers believe that the ocean could harbour microbial life, or evidence of now-extinct microbial life. While scientists generally agree on where to look – underneath the thick, planet-wide ice shell where water is in contact with a rocky core and where biochemical ingredients for life may exist – how to get there to collect samples remains a major tactical problem.

Now, researchers at with NASA’s Glenn Research COMPASS team have devised an idea for a probe that could access that ocean: a nuclear-powered tunneling bot that could burrow through the moon’s icy shell to probe its composition and, potentially, access the watery darkness under it. The bot would also evaluate the habitability of the ice shelf itself.

The researchers dreamed up two versions of the “tunnelbot,” one of which would use a small nuclear reactor and the other of which would use a “radioactive heat source module.” In both cases, the tunnelbot would use excess heat from its reactors to melt the ice as it traveled down. As it went, the tunnelbot would analyze the ice and search it for signs of current or extinct life, reporting back to Earth with a fiber optic cable connected to communication equipment at Europa’s surface.

The bot would sample ice throughout the shell, as well as water at the ice-water interface, and would look at the underside of the ice to search for microbial biofilms. The bot would also have the capability of searching liquid water “lakes” within the ice shell. The NASA-sponsored research is just a concept study. Deploying it would require years of work and extensive precautions against damaging any potential ecosystem on Jupiter’s moon.

Andrew Dombard, a professor of earth and environmental sciences at the University of Illinois at Chicago who worked on the concept said, “We didn’t worry about how our tunnelbot would make it to Europa or get deployed into the ice” and further added “We just assumed it could get there and we focused on how it would work during descent to the ocean.”