Five years ago, the Mars Rover Spirit got stuck in sand on the red planet.Spirit is one of the American space agency's two motorized vehicles on Mars.These incidents led some scientists to develop ways to keep the costly robots from being trapped in the sand.These scientists looked to nature for their ideas.The researchers flew deadly snakes to Zoo Atlanta in Atlanta, Georgia.The snakes, called sidewinder rattlers, are native to the southwestern United States.The creatures were put in a specially designed sandbox with inclines that could be raised up or lowered.The scientists used high-speed video cameras to record the position of the snakes as they moved sideways up different inclines.Their movement is called sidewinding.Daniel Goldman teaches physics at the Georgia Institute of Technology in Atlanta.He says the snakes moved easily in the sand -- even when the sand began moving.
