NASA's ERNEST rover travels 16 miles autonomously, reaching speeds 10x faster than Perseverance

NASA Testing Advanced Capabilities for Moon, Mars Rovers

On a bleak stretch of the Colorado Desert in Southern California, a compact four-wheeled rover recently trundled about 16 miles (26 kilometers) with minimal intervention from the team of engineers trailing it. Called ERNEST (Exploration Rover for Navigating Extreme Sloped Terrain), this prototype is being used by NASA to advance both robotic autonomy and the ability to traverse challenging landscapes. Developed at NASA's Jet Propulsion Laboratory in Southern California, ERNEST is 4 feet (1.2 meters) long. Not only can it lift each of its mesh wheels to get past obstacles that would stymie Curiosity and Perseverance, NASA's six-wheeled Mars rovers, but the prototype also has enhanced independent decision-making capabilities. These mobility and autonomy advances could be infused into future missions that will venture to previously inaccessible areas of the Red Planet or the Moon. In the field, ERNEST served as a testbed for a potential future lunar mission requiring higher speeds and much greater mileage than can be accomplished by current rovers. This technology could be used to inform future designs for exploration efforts on the Moon and beyond. "This testing is helping us refine the mobility hardware and autonomy software to navigate extreme distances across a wide range of terrain and lighting conditions anticipated on the Moon," said Issa Nesnas, a principal technologist at JPL who led the recent testing as head of autonomy for a NASA mission concept for a potential future long-range lunar rover. Nesnas' team is using ERNEST to demonstrate it is possible to build a rover that's twice as big as the prototype and capable of a long-distance Moon mission. During the recent campaign, ERNEST traveled at speeds up to 0.6 mph (1 kph) over 37 hours of driving, across seven days of intermittent testing. That's an order of magnitude above the top speed Perseverance and Curiosity can navigate. "You could do a science road trip across the Moon -- or Mars -- with this vehicle," said James Keane, a JPL planetary scientist working on lunar missions. The initial goal of the team that developed ERNEST was mechanical: to design a relatively simple, low-cost rover that advances the trusted rocker-bogie suspension system featured on every Mars rover since NASA's Sojourner. This passive system keeps relatively constant weight on all six wheels, thanks to pivot points and struts that enable each one to adapt to the changing surface. On ERNEST, the active suspension lets the rover manage weight distribution among its wheels. Two powered joints in front articulate a gimbal that allows the rover to drive using different gaits like squirming, wheel-walking, and obstacle-climbing. With a clutch mechanism, it can switch between active and passive suspension, which is less terrain capable but more energy efficient. With four steerable wheels, it can drive in any direction, including sideways. "We started by postulating that we could do better in designing a planetary surface robotic mobility system," said Hari Nayar, a JPL principal technologist leading the ERNEST team. "While the rocker-bogie system has been very successful over the past 30 years, there's been a lot of research in that time on mobility and understanding terrain interaction." Before arriving at today's version of ERNEST, the team built two earlier prototypes, each about 2 feet (0.6 meters) long, to test 11 active suspension configurations. In a trailer filled with lunar regolith simulant, they ran experiments at different slope angles over several months before landing on a final design. Then the team scaled up, including adding a rectangular head mounted on a 4.5-foot-tall (1.4-meter-tall) mast. The hardware was completed in September 2024, but the rover still needed a human operator to joystick it, sending commands to instruct the rover on how to move over obstacles. In order to train the rover to think on its own, the ERNEST team turned to reinforcement learning, a type of artificial intelligence where the robot learns by interacting with its environment. The Dynamics and Real-Time Simulation Laboratory at JPL developed a high-fidelity virtual testing environment that replicates the rover's behavior. The team fed the simulator data collected by engineers who documented the response of the actual rover hardware to a variety of terrain types. On a high-performance computing cluster, the team ran many simulations at once, sometimes completing thousands of hours of tests over a single weekend. After months of virtual training, the ERNEST team was ready to see if the rover could use its new autonomous algorithms to figure out how to drive over terrain features that would halt a passive-suspension rover. They set up an obstacle course with sand ripples, rubble piles, steps, and steep slopes in JPL's Mars Yard, an outdoor terrain proving ground. Then they watched as the rover maneuvered the terrain on its own. Since then, ERNEST has completed many such courses. Nayar's team is starting a new autonomy project which involves integrating the rover's ability to determine when and how to use its active suspension with longer-range intelligent navigation. The goal is to enable ERNEST to plan an efficient path so that it can tackle surmountable obstacles and circumnavigate hazardous ones. These capabilities could contribute to potential future rover missions encountering formidable landscapes on Mars or more rugged areas of the Moon. Work on ERNEST began in 2022 was initially supported by JPL internal research and development funds. It is currently funded by NASA's Mars Exploration Program and the agency's Exploration Science Strategy Integration Office in its Science Mission Directorate at NASA Headquarters in Washington. Caltech in Pasadena, California, manages JPL for NASA. Media Contacts Karen Fox / Molly Wasser NASA Headquarters, Washington 240-285-5155 / 240-419-1732 [email protected] / [email protected] Melissa Pamer Jet Propulsion Laboratory, Pasadena, Calif. 626-314-4928 [email protected]

Meet ERNEST, NASA's Next-Generation Rover Designed to Be Faster and Tougher

During a recent field test in the Colorado desert, a four-wheeled rover traveled across 16 miles (25 kilometers) in a little over a day and a half, lifting its mesh wheels to drive over obstacles in the rough terrain using enhanced decision-making capabilities. ERNEST, short for Exploration Rover for Navigating Extreme Sloped Terrain, is a small prototype rover built to be more capable of traversing across rugged terrain for future missions that require higher speeds and greater milage. Engineers from NASA's Jet Propulsion Laboratory recently put the rover to the test, trailing behind it as it traveled across the Southern California desert for 37 hours. A worthy successor Since 1997, NASA has sent a total of five rovers to Mars, each with enhanced capabilities to explore the otherworldly terrain and gather data on its potentially habitable past. The Curiosity and Perseverance rovers, which landed in 2012 and 2021, are still roaming Mars to this day. For future missions to the Moon and Mars, NASA needs its robotic explorers to be more capable of wheeling past obstacles on rugged terrains. That's where ERNEST comes in. The next-generation rover is equipped with more advanced mobility and autonomy that could be used to venture to previously inaccessible regions on upcoming missions. During the recent field test, ERNEST traveled at speeds up to 0.6 miles per hour (1 kilometer per hour) across seven days of intermittent testing. That's an order of magnitude above the top speed Perseverance and Curiosity can navigate, according to NASA. "You could do a science road trip across the Moon -- or Mars -- with this vehicle," James Keane, a JPL planetary scientist working on lunar missions, said in a statement. ERNEST is equipped with a suspension system that lets the rover manage weight distribution among its wheels. The rover can drive using different gaits like squirming, wheel-walking, and obstacle-climbing thanks to two powered joints in the front. Using its four steerable wheels, ERNEST can drive in any direction, including sideways. "We started by postulating that we could do better in designing a planetary surface robotic mobility system," Hari Nayar, a JPL principal technologist leading the ERNEST team, said in a statement. "While the rocker-bogie system has been very successful over the past 30 years, there's been a lot of research in that time on mobility and understanding terrain interaction." The making of ERNEST ERNEST is smaller than its SUV-sized predecessors at only 4 feet (1.2 meters) long. Before building this current version of the rover, the team designed two earlier prototypes at about 2 feet (0.6 meters) long for earlier experiments in a trailer filled with material to simulate lunar regolith. After scaling up to ERNEST's current design, the team decided they wanted the rover to think on its own. The engineers used reinforcement learning, a type of artificial intelligence where the robot learns by interacting with its environment. The autonomous algorithm was first put to the test in an obstacle course with sand ripples, rubble piles, steps, and steep slopes in JPL's Mars Yard. Finally, in March, the team took ERNEST out for its first field test, following the rover as it traversed autonomously across the desert. ERNEST was even put to the test in complete darkness to see how well it could travel at dusk and dawn on the Moon, when shadows are long. "This testing is helping us refine the mobility hardware and autonomy software to navigate extreme distances across a wide range of terrain and lighting conditions anticipated on the Moon," Issa Nesnas, a principal technologist at JPL, said in a statement. One day, a larger, faster version of ERNEST could potentially be used in a future mission to the Moon.