The 'Bridget' (L), 'Bryan' (C) and 'Bruno' (R) rovers are shown on the Mars Yard test area at Airbus Defence and Space in Stevenage, England on March 27, 2014.  The Mars Yard provides a test bed area for prototype 'Rover' vehicles that may be used to provide data from the surface of the planet Mars. AFP PHOTO / LEON NEAL        (Photo credit should read LEON NEAL/AFP/Getty Images)