NASA’s Snake-Like Robot Could Look for Life on an Icy Saturn Moon

Designed to weather the toughest of terrains, EELS might one day autonomously move through narrow vents on Enceladus

The Exobiology Extant Life Surveyor explores a moon's icy cavern
Using stereo cameras and lidar, EELS is able to create a 3D map of its surroundings, understanding the environment before navigating through it. NASA / JPL-CALTECH

NASA is testing a snake-like robot in hopes that it could one day look for life on Saturn’s icy moon Enceladus. Developed by NASA’s Jet Propulsion Laboratory (JPL), the 220-pound and 13-foot-long machine is called EELS, or the Exobiology Extant Life Surveyor, and it’s designed to be “self-propelled” and “autonomous,” according to a statement from the agency.

While the robot is still undergoing testing and development, engineers hope it will soon independently slither through a variety of planetary and lunar terrains—from undulating sand and ice to steep cliffs, gaping craters, underground lava tubes and even narrow spaces within glaciers.

“It has the capability to go to locations where other robots can’t go. Though some robots are better at one particular type of terrain or other, the idea for EELS is the ability to do it all,” Matthew Robinson, EELS project manager, says in the statement. “When you’re going places where you don’t know what you’ll find, you want to send a versatile, risk-aware robot that’s prepared for uncertainty—and can make decisions on its own.”

Since the robot’s first prototype was produced in 2019, engineers have trialed and revised their design continuously. They tested the robot in a variety of environments—from JPL’s own simulated Martian landscape, called the Mars Yard, to the snowy mountains of Southern California.

Testing Out JPL's New Snake Robot

JPL engineers hope the robot can eventually solve problems without human input. Due to time lags in communication between us and Enceladus, EELS needs to calculate risk, move around and collect data without the help of a team on Earth. Using stereo cameras and lidar, the robot can create a 3D map of its surroundings to understand its environment before navigating through it.

The team has likened themselves to a start-up, saying their mentality is to “build quickly, test often, learn, adjust, repeat.” Whatever scientists ask of the robot, the engineers will try to achieve it.

“We have a different philosophy of robot development than traditional spacecraft, with many quick cycles of testing and correcting,” Hiro Ono, EELS principal investigator, says in the statement. “There are dozens of textbooks about how to design a four-wheel vehicle, but there is no textbook about how to design an autonomous snake robot to boldly go where no robot has gone before. We have to write our own.”

The project’s long-term destination, Enceladus, is one of our solar system’s most scientifically interesting sites. When NASA’s Cassini probe studied the moon, it revealed an ocean of liquid salt water below an icy crust—with cold-temperature geysers that expel plumes of gas, dust and ice. Cassini’s observations suggested Enceladus could be habitable, and EELS could one day follow up on this research, investigating whether life exists on the icy world.

Scientists hope to finish EELS by the fall of 2024. However, after the robot is built, it would take about 12 years for a spacecraft to carry EELS to the distant moon. Once there, it could descend through one of Enceladus’s geyser vents and study its vast ocean.

“We are early in the project, but it is achievable in our lifetime,” Rachel Etheredge, EELS deputy project manager, said last year, per Li Cohen of CBS. “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.”

Get the latest stories in your inbox every weekday.