NASA’s Jet Propulsion Laboratory has successfully advanced the development of next-generation planetary rovers following a recent field test of ERNEST, a prototype engineered for extreme terrain traversal. Conducted across the Colorado Desert in Southern California over seven days, the campaign validated critical mobility hardware and autonomy software intended for future long-range missions to the Moon and Mars. Developed under the leadership of JPL principal technologists Hari Nayar and Issa Nesnas, ERNEST represents a significant departure from the traditional rocker-bogie suspension systems that have powered NASA’s six-wheeled Mars rovers since the 1990s. Instead, the four-wheeled prototype utilizes an active suspension system with powered joints and a clutch mechanism. This architecture enables dynamic weight distribution, allowing the vehicle to shift between energy-efficient passive mode and highly capable active modes. Equipped with a gimbal assembly, ERNEST can adapt its gait to squirm, wheel-walk, or climb over obstacles that would immobilize conventional designs, while also maintaining the ability to steer in any direction. To overcome historical limitations in planetary rover speed, the JPL team integrated reinforcement learning algorithms into ERNEST’s navigation stack. After months of high-fidelity virtual training using a simulated lunar regolith environment, the rover transitioned to autonomous operation. During the desert campaign, ERNEST traveled 16 miles over 37 hours at speeds reaching 0.6 miles per hour, achieving a tenfold increase in velocity compared to the operational limits of the Curiosity and Perseverance rovers. The prototype successfully navigated complex obstacle courses, including sand ripples, rubble piles, and steep inclines, with minimal human intervention. The successful field demonstration confirms the viability of scaling the ERNEST architecture into larger vehicles capable of extended planetary surface exploration. Project scientists, including planetary scientist James Keane, note that these advancements could enable sustained, high-speed scientific campaigns across previously inaccessible lunar craters and Martian highlands. JPL is now focusing on integrating ERNEST’s terrain-adaptive suspension controls with long-range intelligent path planning, a critical step toward autonomous missions that can evaluate hazards in real time and optimize routes across vast extraterrestrial landscapes. The technology baseline established by this prototype will directly inform the engineering specifications for upcoming NASA exploration initiatives targeting the Moon and Mars.