Robotic Snake, Coming to a Glacier Near You
Illustration of the Exobiology Extant Life Surveyor (EELS) robot – currently in development – Credit NASA/JPL-CalTech
This fall, NASA’s robotic snake, EELS, will slither around the Athabasca Glacier, an icy tongue of the Columbia Icefield in Jasper National Park. The EELS team will test the snake’s ability to travel through crevasses and other ice features in the hope that one day it will help search for extraterrestrial life in the subterranean ocean of Saturn’s moon Enceladus.
The development of EELS follows discoveries made by the Cassini probe that spent 13 years exploring Saturn, its rings, and moons before plunging (on schedule) into Saturn’s atmosphere and burning up in Sept 2017. Among many fascinating finds, Cassini discovered over 100 jets spewing water vapour into space from fractures in the surface ice at the southern pole of Enceladus. These plumes are the likely source of Saturn’s E ring. Cassini was also able to detect other elements in the plumes, including amino acids that are considered necessary ingredients for life.
EELS Team members, Peter Gavrilov and Phillipe Tosi take measurements in advance of the first overnight test at the Pasadena Ice Rink – Credit NASA/JPL-CalTech
“The big question is whether there is alien life on Enceladus, and if there is, how do you get in there to find it?” explains Masahiro Ono, the Project Lead on Robotic and Surface Mobility and EELS Principal Investigator. The most likely place to find life would be in the ocean beneath the moon’s icy crust, possibly near hydrothermal vents. But how to get through the kilometres of surface ice surrounding the moon? That’s where the EELS concept comes in. The idea is to design a snake-like robot that can maneuver its way to the subsurface ocean through the deep fractures in the ice.
It’s not an easy task, given the number of unknowns. Ono says they don’t know the exact width of the vents in the ice, and with what force the water vapour is being forced through them. And then there’s the cold — the surface temperature on the moon’s icy surface is around minus 198 degrees Celsius. “The point is to be robust to a wide range of possibilities,” says Ono. Earth analogue tests, like the one on the Athabasca Glacier this fall, are a step toward building the robot’s resilience.
“The primary goal in the field is to see what types of glacial terrain the robot can handle, both on the surface and in subsurface features like crevasses and moulins,” explains Michael Paton, the robotics technologist leading the field tests. He says one of the strengths of a snake robot is its ability to change shapes and adopt different gaits to overcome challenging environments. The robot’s body is threaded with rotating screws similar to a drill, which can both propel the snake, and help it grip into the ice. The field tests will evaluate the limits of the EELS robot’s different capabilities in order to refine them for a possible mission.
EELS team members, Masahiro (Hiro) Ono, Rohan Thakker, Marlin Strub, Phillipe Tosi and Michael Paton carry the 9-link EELS robot to the ice at the Pasadena Ice Rink – Credit NASA/JPL-CalTech
The team aims to finish refinements to the EELS concept by the Fall of 2024, after which they hope to propose an Enceladus mission to NASA. “We are early in the project, but it is achievable in our lifetime,” says Rachel Etheredge, the EELS Deputy Project Manager. If approved, a spacecraft carrying EELS would take roughly 12 years to reach Enceladus. Once deployed to a vent, it is hoped to take just a matter of days for the snake to reach the ocean, and the findings communicated from the moon would reach Earth within hours.
There will be many steps in the ladder that leads to lift off. “It’s an ambitious collaboration, and we’re motived by the shared excitement we have for this concept, and the potential science we could gather with EELS,” says Etheredge. In the meantime, the journey continues on the Athabasca Glacier this September.
500 Connaught Drive
Jasper, AB, Canada T0E 1E0