Madison Reporter

Robotic space rovers often face challenges when navigating extraterrestrial terrains, such as getting stuck in soft sand or gravel. The University of Wisconsin–Madison's mechanical engineers have identified a flaw in the testing process that could prevent these issues in future missions.

Mechanical engineering professor Dan Negrut and his team discovered that traditional Earth-based testing methods do not accurately simulate the conditions on celestial bodies like the moon or Mars. The gravitational pull on Earth affects how sand behaves, making it more rigid and supportive than it would be under weaker lunar gravity. This discrepancy can lead to overly optimistic conclusions about rover performance.

Negrut explained, “In retrospect, the idea is simple: We need to consider not only the gravitational pull on the rover but also the effect of gravity on the sand to get a better picture of how the rover will perform on the moon.” Their findings were published in the Journal of Field Robotics.

The research was part of a NASA-funded project simulating the VIPER rover for a planned lunar mission. Using Project Chrono, an open-source physics simulation engine developed at UW–Madison, researchers identified discrepancies between Earth-based tests and simulations conducted for lunar conditions.

Beyond space exploration, Chrono has applications for various industries on Earth. It helps organizations understand complex mechanical systems, from precision watches to military vehicles operating off-road. Negrut expressed pride in their achievements: “It’s rewarding that our research is highly relevant in helping to solve many real-world engineering challenges.”

Chrono is freely available worldwide, with ongoing development and support from UW–Madison. Despite being open source, Negrut emphasized their commitment to innovation: “All our ideas are in the public domain and competition can adopt them quickly... We have been fortunate over the last decade to receive support from... NASA.”

This work received funding from NASA STTR (80NSSC20C0252), National Science Foundation (OAC2209791), and U.S. Army Research Office (W911NF1910431 and W911NF1810476).