ESA’s Gaia mission is generating an enormous amount of data as it works to plot the position of a billion stars in three dimensions. But during pre-flight testing one of Gaia’s memory modules – part of the spacecraft’s onboard ‘hard disk’ – failed. ESA’s Materials and Electrical Components Laboratory was called in to assess the failure, to see if it was a one-off or else caused by a general manufacturing issue. The team made use of their 3D X-ray Tomography Machine to perform non-destructive internal scanning of the module and pin down the source of the fault.