May 23, 2012
Tumbleweed Inspires Next Generation Mars Rover Design
Lee Rannals for RedOrbit.com
North Carolina State University researchers are proposing that a wind-driven "tumbleweed" Mars rover would be capable of moving across the Red Planet's rocky terrain.
The scientists 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 Martian rock fields, which are common on the surface of the planet.
“We found that, in general, the larger the diameter, and the lower the overall weight, the better the rover performs,” Dr. Andre Mazzoleni, an associate professor of mechanical and aerospace engineering (MAE) at NC State and co-author of a paper describing the research, said.
The researchers found that a tumbleweed rover would need to have a diameter of at least 20 feet in order to achieve an acceptable level of performance.
They also determined that tumbleweed rovers are more likely to bounce than roll across the surface, due to the space of the rocks and the size of the rovers.
“Computer simulations are crucial for designing Mars rovers because the only place where you find Martian conditions is on Mars,” says Mazzoleni. “Earth-based testing alone cannot establish whether a particular design will work on Mars.”
Mars has just about 3/8 the gravity that Earth has, and the atmospheric density on its surface is only duplicated about 100,000 feet above the Earth's surface.
Tumbleweed rovers would be able to cover much larger distances, and handle rougher terrain, than those rovers like Spirit and Opportunity that have already been sent to Mars.
“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.
The rover design would lack precise controls that wheeled rovers have, but would not need to rely on a power supply for mobility.
The findings, which were published in the Journal of Spacecraft and Rockets, could help NASA design a more efficient next-generation Martian vehicle.
“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,” Mazzoleni said. “We set out to address that question.”
NASA's latest Mars rover, Curiosity, is currently in route to the Red Planet. The rover is about five times larger than the Spirit and Opportunity rovers, and carries more than ten times the amount of scientific instruments.
Image 2 (below): Model of a tumbleweed rover. Credit: North Carolina State University