How EELS will work
EELS is a snake-like, self-propelled robot made of multiple segments. It is currently in development and several prototype versions have been built, with some capabilities still undergoing testing.
Each segment of EELS has independently actuated counter-rotating screws that provide propulsion, traction, and grip. Because of its segmented design, EELS can take on various shape configurations to widely adapt its mode of propulsion to use whatever is best suited to the challenges of its terrain. EELS uses stereo cameras and lidar to create 3D maps of its surroundings, then uses artificial intelligence to make autonomous decisions about where and how to move through its environment.
Because of all of this adaptability, EELS is capable of exploring extremely challenging terrain in unknown environments. Its use of AI to autonomously make decisions also means it doesn’t have to rely on controllers on Earth, meaning the robotic explorer can make decisions in real-time instead of waiting for commands that take hours to reach it.
Because EELS is designed to study its environment as well as navigate through it, it has been modeled with several possible methods of collecting data or retrieving samples. One model involves a payload segment that would carry science instruments or even deploy a Cryoegg, a spherical, wireless sensor package designed to drop into subglacial water and take measurements. EELS may also wind up being designed to collect samples beneath the ice, crawl back to the surface, and return those samples to a lander. Current EELS prototypes are still focusing on locomotion, with data collection capabilities planned for future iterations of the robot.
Proving EELS as an Enceladus explorer
While a robot like EELS could be used to explore a variety of worlds, its target right now is Enceladus. The team’s main goal is for the robot to be able to explore the surface of Enceladus, find the best place to get into the ice, descend down one of these cracks adapting its shape and movement as it does so, and then reach the subsurface ocean and test for signs of life.
In September 2023, EELS proved its ability to handle the kind of environment it might encounter on Enceladus. The mission team conducted field tests at Athabasca Glacier in Alberta, Canada, where moulins (glacial crevasses) provide some of the best earthly analogs of Enceladus’ fissures.