'Tumbleweed' design could be Mars rover

RALEIGH, N.C., May 23 (UPI) -- U.S. scientists say a wind-driven "tumbleweed" Mars rover could be the best design for a scientific vehicle capable of moving across rocky Martian terrain.

Researchers at North Carolina State University say their findings could help NASA in its quest for the next generation of such robot rovers.

"There is quite a bit of interest within NASA to pursue the tumbleweed rover design, but one of the questions regarding the concept is how it might perform on the rocky surface of Mars," Andre Mazzoleni, a professor of mechanical and aerospace engineering, said. "We set out to address that question."

Mazzoleni and colleague Alexander Hartl developed a computer model to determine how varying the diameter and mass of a tumbleweed rover would affect its speed and ability to avoid getting stuck in rock fields, common on the Red Planet, that average one rock per square yard.

"We found that, in general, the larger the diameter, and the lower the overall weight, the better the rover performs," Mazzoleni said.

A tumbleweed rover would need to have a diameter of at least 20 feet to move through rock fields without getting stuck, the researchers said.

Tumbleweed rovers could cover much larger distances and handle rougher terrain than the rovers already sent to Mars such as Spirit and Opportunity, they said.

"This model is a tool NASA can use to assess the viability of different designs before devoting the time and expense necessary to build prototypes," Mazzoleni said.