40. 04/10/2014

Nasa's Curiosity rover landed on the surface of Mars in August 2012 after a nine month journey in space. Its mission is to continue the space agency's exploration of the Red Planet, analyse its rocks, look for water and prepare for human exploration. BBC Click's Spencer Kelly has been given rare access to its earthbound twin at Nasa's Jet Propulsion Laboratory where scientists are using the machine to help them solve problems its Mars counterpart might experience.