NASA's ERNEST Rover Tests Advanced Mobility for Moon and Mars Missions

NASA is advancing robotic autonomy and terrain traversal capabilities for future lunar and Mars missions through testing of a new rover prototype named ERNEST (Exploration Rover for Navigating Extreme Sloped Terrain). Developed at NASA's Jet Propulsion Laboratory (JPL), the 4-foot-long, four-wheeled rover recently completed a 16-mile journey in the Colorado Desert with minimal human intervention. ERNEST's design features include mesh wheels that can be lifted to overcome obstacles, a capability exceeding that of current Mars rovers like Curiosity and Perseverance.

The rover is being used to refine hardware and software for navigating extreme distances across diverse terrain and lighting conditions anticipated on the Moon. ERNEST's testing is informing designs for potential future missions requiring higher speeds and greater mileage than current rovers can achieve. During recent field tests, ERNEST traveled at speeds up to 0.6 mph, an order of magnitude faster than its Mars counterparts, over seven days of intermittent operation.

ERNEST's mobility system builds upon the trusted rocker-bogie suspension found on Mars rovers but incorporates active suspension with powered joints. These allow the rover to manage weight distribution and employ various gaits, such as squirming and obstacle-climbing. It can also switch to a more energy-efficient passive suspension mode. With four steerable wheels, ERNEST offers omnidirectional movement, including sideways driving.

Previous iterations of ERNEST, smaller prototypes, were used to test 11 active suspension configurations in simulated lunar regolith. The current version, completed in September 2024, is now being trained using reinforcement learning. A high-fidelity virtual testing environment developed at JPL replicates the rover's behavior, allowing for thousands of hours of simulated tests to be conducted rapidly, enabling the rover to learn to make independent decisions.