Electric cars may still play second fiddle to petrol here on Earth, but they've dominated the Martian driving scene for more than a decade.
NASA's tiny Sojourner rover hit the red dirt in 1997, followed by the golf-cart-size twins Spirit and Opportunity in 2004. And last August, the 1-ton Curiosity rover dropped in to determine whether Mars could ever have supported microbial life.
All three generations of six-wheeled NASA rovers have used electric power systems of various design and complexity to find their way around the Red Planet.
there is water on Mars