The search for extraterrestrial life will continue not just on the surfaces of planets, but deep within their icy cores.
For decades, rovers and landers on planets such as Mars have either examined or roamed the surface to find evidence for flourishing microbial life, or at least the ancient remnants of it. However, this could be all about to change with the development of a new robot that can burrow deep within a planet’s surface.
Designed by engineers at the University of Illinois at Chicago, the ‘tunnelbot’ is a nuclear-powered machine capable of piercing and diving into the thick, ice shell of Jupiter’s moon Europa, where water is in contact with a rocky core. Since NASA’s Galileo spacecraft made several flybys of the moon a number of years ago, astrobiologists have said that these conditions could harbour microbial life or show evidence of it having once existed there.
Until now, suggestions of how to actually reach this part of the planet were very limited, with the ice shell range being between 2km and 30km thick. If the tunnelbot is to succeed, it needs to be able to both tunnel through this distance and reach Europa’s ocean. Then, it needs to turn on its array of instruments to search for life and return findings to Earth.
What it will do
Andrew Dombard, along with his spouse and associate professor in Earth and environmental sciences, D’Arcy Meyer-Dombard, designed the tunnelbot to sample ice through the shell, as well as the water in the ocean below. It also aims to search the underside of the ice for microbial life, as well as liquid water ‘lakes’ within the ice shell.
When thinking about how to power it, the pair came to a choice between two methods: one being general purpose heat source bricks, which use radioactive heat source modules designed for space missions; and the second being a small nuclear reactor. Either solution would be hot enough to help melt the ice as it travels down.
Meanwhile, to communicate with Earth, the tunnelbot would use a string of ‘repeaters’ connected to the robot by fibre optic cables.
As for how the tunnelbot would get to Europa in the first place, the pair said they weren’t concerned with that just yet. “We didn’t worry about how our tunnelbot would make it to Europa or get deployed into the ice,” Dombard said. “We just assumed it could get there and we focused on how it would work during descent to the ocean.”