NASA’s Mars rovers have accomplished a lot since the first one landed on the red planet in the late ’90s, but even the latest members of the fleet still have many limitations. On the one hand, they are very slow; Perseverance, which NASA considers “outstanding,” reaches a top speed of just under 0.1 mph on flat terrain. In addition to that, the rugged terrain is hard on the wheels of the roversand steep slopes with hazards like rocks and sand pose a real challenge, sometimes requiring long detours to achieve certain objectives. But this week, POT showed its progress in a prototype that has more advanced capabilities: the Exploration Rover for navigating terrain with extreme slopes, or Ernest.
The space agency has been testing Ernest in the Colorado desert, exploring new approaches that could be used for future missions to Mars and the Moon. Ernest has four wheels, in contrast to the six on current Mars explorers, and is four feet long, although a version that would be used for an actual mission would be twice the size. And it can individually lift its wheels to step on or overcome obstacles. In recent desert testing, the prototype drove for a total of more than 37 hours over seven days, covering approximately 16 miles, according to NASA. It reached a top speed of about 0.6 mph.
“You could do a scientific road trip across the Moon (or Mars) with this vehicle,” said James Keane, a planetary scientist at JPL who works on lunar missions. Going back to NASA’s Sojourner rover, Mars rovers have relied on a passive suspension system, the rocker-bogie system, to keep weight constant on their wheels. Now, however, engineers are testing active suspension with Ernest for greater mobility. “Two motorized joints in the front articulate a gimbal that allows the rover to drive using different modes of movement, such as twisting, wheel walking, and climbing obstacles,” NASA says.
It can switch between active and passive suspension depending on the task and energy needs and, thanks to its four steerable wheels, it can travel in any direction. There have already been multiple iterations of the Ernest prototype since the program began in 2022, and the team has tested nearly a dozen active suspension configurations. The latest version also has “enhanced independent decision-making capabilities.” Ernest’s goal is to develop technology for rovers that can cover more ground than previous ones, and faster, with less dependence on human controllers on Earth.
