A rubble-strewn model of the Red Planet used to put prototype planetary rovers through their paces: officially known as the Automation & Planetary Robotics Laboratory, its nickname is the ‘Mars Yard’. An 8 x 8 m square filled with sand and different sizes of gravel and rocks, it is used to assess rover locomotion and navigation as well as the positioning of robotic arms – then check how these elements work together in practice.