Bricks have been 3D printed out of simulated moondust using concentrated sunlight. This ESA project took place at the DLR German Aerospace Center facility in Cologne, with a 3D printer table attached to a solar furnace, baking successive 0.1 mm layers of moondust at a temperature of 1000°C. A 20 x 10 x 3 cm brick for building can be completed in around five hours. DLR Cologne’s solar furnace has two working setups: as a baseline, it uses 147 curved mirror facets to focus either actual sunlight into a high temperature beam, employed to melt together the grains of regolith. But this mode is weather dependent, so a solar simulator was subsequently employed as well – based on an array of xenon lamps more typically found in cinema projectors.