TL;DR
NASA’s ERNEST rover prototype drove 16 miles in 37 hours during desert testing, hitting 0.6mph. That is 10x faster than Perseverance or Curiosity on Mars.
NASA’s Jet Propulsion Laboratory has built a rover prototype that covered 16 miles in 37 hours of driving, making it roughly 10 times faster than any rover the agency currently operates on Mars. The four-wheeled machine, called ERNEST, reached speeds of up to 0.6mph during a field test in California’s Colorado Desert in March 2026. That pace would be unremarkable for a human on foot, but for a planetary rover it represents a fundamental shift in what robotic exploration could look like.
ERNEST stands for Exploration Rover for Navigating Extreme Sloped Terrain. The prototype is 4 feet long and runs on mesh wheels, a departure from the rigid aluminium wheels that have caused problems on Mars. Its defining feature is an active suspension system with two powered joints per wheel, allowing the rover to lift individual wheels over obstacles, drive sideways, and switch between gaits including what JPL describes as “squirming,” wheel-walking, and obstacle-climbing modes.
A clutch mechanism lets ERNEST toggle between active and passive suspension on the fly. In passive mode, the rover conserves energy on flat terrain. In active mode, it can tackle slopes and obstacles that would stop or strand the rocker-bogie suspension system used on every NASA Mars rover since Sojourner landed in 1997.
The speed matters because current Mars rovers are extraordinarily slow. Curiosity, which landed in 2012, and Perseverance, which arrived in 2021, both top out at roughly 0.06mph. NASA has sent five rovers to Mars since 1997, and only Curiosity and Perseverance are still operational.
Their pace is limited partly by their suspension design and partly by the cautious navigation software that governs how they move across unfamiliar terrain. ERNEST addresses both problems.
JPL trained the rover’s navigation system using reinforcement learning in its DARTS simulation lab, running thousands of virtual driving hours across procedurally generated terrain before the machine ever touched real ground. The approach lets the rover make faster decisions about where to place its wheels without waiting for human commands from Earth, where signal delays to Mars run between four and 24 minutes each way.
The Colorado Desert test was not the rover’s first outing. JPL first tested ERNEST in its Mars Yard obstacle course at the Pasadena campus, then moved to the desert for a more realistic trial across natural terrain. The team ran the rover in darkness to simulate the dim lighting conditions at the lunar south pole, where future missions would operate during dusk and dawn periods.
Over seven days of intermittent testing, ERNEST accumulated its 16 miles of driving in 37 hours of actual movement.
Before the current 4-foot prototype, JPL built two smaller versions at 2 feet long and tested 11 different suspension configurations to arrive at the final design. Hardware on the current prototype was completed in September 2024. Work on the project began in 2022, initially funded by JPL’s internal research and development budget.
The project has since attracted outside funding. NASA’s Mars Exploration Program and its Exploration Science Strategy and Integration Office are now backing the work, a signal that the agency sees ERNEST’s technology as more than a lab experiment. Hari Nayar, the JPL principal technologist leading the ERNEST team, and Issa Nesnas, who led the field testing, have said a larger and faster version of the rover could eventually be used for a Moon mission.
A lunar application makes strategic sense. NASA is increasingly relying on commercial partners to lower the cost of planetary missions, and a faster rover would allow the agency to cover more ground during the limited operational windows available at the lunar poles, where sunlight and power are intermittent.
The rocker-bogie suspension that ERNEST is designed to replace has been remarkably durable. It carried Sojourner, Spirit, Opportunity, Curiosity, and Perseverance across Mars, and Opportunity in particular drove more than 28 miles over 15 years on the system. But the design prioritises stability over speed, and it cannot actively adapt to terrain the way ERNEST’s powered joints allow.
JPL planetary scientist James Keane has pointed to the rover’s potential for exploring regions that are currently inaccessible, including steep crater walls, lava tubes, and the permanently shadowed regions near the lunar south pole where water ice is believed to exist. Those are environments where a rover that can lift its own wheels and change its gait would have a meaningful advantage over one that relies on passive geometry to stay upright.
It is worth noting that ERNEST remains a prototype, not a flight-qualified vehicle. The gap between a successful desert test and a rover that can survive launch, landing, and years of operation on another world is substantial. JPL has not announced a specific mission for the technology or a timeline for when a flight version might be ready.
Still, 16 miles in 37 hours is a number that changes the conversation about what rovers can do. Curiosity has driven roughly 21 miles in 14 years on Mars. ERNEST covered three-quarters of that distance in a week.
Stephan is the sports journalist for the Maple Grove Report.
