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Monday, May 28, 2012

The tumbleweed Martian rover

Just when you thought Mars rovers couldn’t get any cooler, here comes the ‘tumbleweed rover’. As the name implies, this is a rover that would travel across the Martian landscape driven solely by wind power. You can see an artist’s rendition of such a rover below.


Credit: North Carolina State University.

Because conditions on Mars are unlike anything that can be found on Earth, designing such a rover requires computer models and simulations. Alexandre Hartl and Andre Mazzoleni of North Carolina State University created their own simulations of Martian rock fields and wind patterns to virtually test various types of rovers.

The researchers compared rovers of different sizes and weights to determine the optimal design. Not surprisingly, lightweight rovers with large diameters were able to travel the furthest in the same amount of time under the same wind conditions. This is partly because they present a larger surface area to the wind, and partly because larger rovers can more easily bounce over obstacles. Perhaps most importantly, larger rovers don’t require as much wind to dislodge them from behind rock formations or to get them going again once they’ve stalled.

The obvious advantage of using a tumbleweed rover is that it would not expend any energy traveling from place to place. It could therefore save all its power for sample collection, data analysis, communication with Earth and other tasks. In addition, such a rover could potentially travel great distances from its landing site over a variety of terrains.

The obvious disadvantage is that the rover might never happen to reach those regions of greatest interest to areologists. Remember, there is no way to steer these rovers. Still, the much lower cost of these lightweight rovers could allow for hordes of the devices to be deployed with the hope that they would eventually spread across the planet.

By the way, if you pictured these rovers sedately rolling along, you have the wrong image in your mind. They would most likely spend more time bouncing than rolling.

The two-year-old clip below shows some examples of tumbleweed rover designs.