What’s different about NASA’s new Mars rover? Better wheels!
When the next mission to Mars blasts off from Cape Canaveral in Florida on July 30, the rover on board will be sporting a new wheel design — thanks, in part, to Concordia researcher Krzysztof “Chris” Skonieczny.
Skonieczny and his collaborators at NASA and Carnegie Mellon University developed guidelines and equations to optimize the rover’s metal wheels.
“We came up with ways to improve their performance on Mars’s loose and rocky soil,” explains Skonieczny, associate professor and Tier 2 Canada Research Chair in Aerospace Robotics in the Department of Electrical and Computer Engineering at the Gina Cody School of Engineering and Computer Science.
“People joke about not needing to reinvent the wheel, but we did.”
Perseverance on Mars
The Mars 2020 Mission spacecraft and its new rover named Perseverance will take flight on an Atlas V-541 rocket — the same type of rocket that launched Curiosity, the last rover, in 2011.
“To cut down on costs, this new rover was supposed to be a clone of Curiosity, which is considered an overall success,” explains Skonieczny.
“But the one main upgrade relative to Curiosity was the wheels. They were too light, we learned, and the metal was prone to dent, puncture and tear on the jagged rocks, limiting their lifespan.”
Using Curiosity as a case study, Skonieczny and his fellow researchers collected their accumulated knowledge of wheels on Martian terrain and determined that the metal wheels needed more “grousers” — which are like metal cleats — and the grousers needed to be closer together in order to gain more traction.
The grouser’s height, too, influences performance, as does their pattern.
“Results showed that chevron-patterned grousers achieve efficient motion on benign terrain while straight grousers are better for steep slope ascent,” says Skonieczny.
Skonieczny, along with his collaborator Scott Moreland at the NASA Jet Propulsion Laboratory in Pasadena, California, and researchers Hiroaki Inotsume and David Wettergreen from Carnegie Mellon University in Pittsburgh, Pennsylvania, published their findings last year in the Journal of Terramechanics. Those findings were incorporated into the new wheel design at NASA.
“We needed to take into consideration the fact that the soil is much looser because Martian gravity is lower, at 38 per cent of Earth’s gravity,” adds Skonieczny, who says he dreamed of working with NASA since he was a child.
“The wheels need to be able to handle sharp, jagged rocks, but we can’t simply make the wheels heavier because every gram counts when you’re launching in a rocket. And each rover covers new terrain, so there are always variables. We got better results in the lab by redesigning the grousers and changing their placement.”
The Mars 2020 Mission’s goal is to collect soil samples, in search of possible past microbial life.
“This mission will collect samples and stash them for the next mission to retrieve,” says Skonieczny, who is a member of the Concordia Institute of Aerospace Design and Innovation. “We want to help them get where they need to go as efficiently as possible.”
After blast off, it will take up to two years to get results about Perseverance’s new wheel design.
“In this business, you have to be patient,” says Skonieczny.
He recalls watching the SpaceX launch in late May 2020, under quarantine, while his six-year-old son played with a toy rocket.
“We’re both really excited about the next launch in July,” says Skonieczny. “There’s a chance this could run in the family.”
Learn more about the Gina Cody School of Engineering and Computer Science.