Snakes on a Rocket

In the rapidly advancing world of robotics, scientists and engineers are constantly pushing the limits of what these machines are capable of. One of the key factors that determines a robot's success in a given task is its unique design, and increasingly, designers are tailoring robots to be specialized for different environments and purposes.

Perhaps one of the most exciting areas of robot design is in the development of autonomous vehicles. These robots must be able to navigate complex environments, make decisions in real time, and avoid obstacles and hazards. They often use advanced sensors and machine learning algorithms to interpret their surroundings and make decisions about how to proceed.

On the other hand, robots designed for use in factories or warehouses have a different set of requirements. They need to be able to move quickly and precisely, often in tight spaces, and must be able to manipulate objects with a high degree of accuracy.

And then there are robots designed for exploration in space or on other planets. Certainly, they must be able to withstand extreme temperatures, radiation, and other harsh conditions. But, what exactly are those conditions? As our explorations reach farther out into the solar system and beyond, our understanding of the answer to that question diminishes. After all, the robot that we send may be the very first explorer of a new frontier.

How then are we to properly equip these machines for the unknown? A team of engineers at NASA’s Jet Propulsion Laboratory believe the solution is to build a robot that is versatile enough to go just about anywhere. With Saturn’s icy moon Enceladus in mind, they created a thirteen foot long, 220 pound snake-like robot that can slither its way over difficult terrain and through tight spots.

Named EELS (Exobiology Extant Life Surveyor), a robot like this one may one day crawl along the surface of Enceladus, autonomously searching for a narrow surface vent that it can crawl down to enter the hidden ocean below to search for signs of life. Testing here on Earth is building confidence that this may be possible in the future — EELS has been demonstrated to choose safe paths through difficult terrain without outside intervention. This includes challenging terrain like sand, ice, cliff walls, and craters that are too steep for rovers to climb.

The snake-like robot consists of ten segments joined with flexible interconnects that twist like screw threads to provide propulsion, traction, and grip. They have been able to innovate and move fast by taking a startup-like approach to their work, in contrast with the more traditional development practices associated with building spacecraft. This has enabled them to rapidly iterate on new designs that can better handle different types of turf. They have even 3D-printed plastic screws to help EELS adapt to looser terrain, or to get a better grip on icy surfaces.

To get a handle on its surroundings, EELS leverages four pairs of stereo cameras and a lidar sensor to create a three-dimensional map. A navigation algorithm then uses this information to create a travel plan that will help the robot to autonomously achieve its goals. This motion plan can be quite complex, with 48 actuators to control. Ultimately, the engineers plan to develop a set of standard types of movement that the robot can perform, each suited to a particular type of environment.

Thus far, the focus has been on getting the robot around — locomotion and navigation. But for its future explorations to be useful and informative, EELS will also need to carry scientific instruments onboard. They plan to tailor this suite of instrumentation to the robot’s destination and research goals.