Funded by the Italian space agency ASI, the POP3D (Portable On-Board Printer) for 3D printing reached orbit in 2015. The compact, cube-shaped printer measures 25 cm per side and weighs 5.5 kg in Earth gravity. It prints in biodegradable and harmless PLA plastic, using a heat-based process called ‘fused filament fabrication’. POP3D typically takes about half an hour to produce a single plastic part, which was subsequently returned to the ground for detailed testing, including comparison to an otherwise identical part printed on the ground. The Italian Institute of Technology assisted with post-flight examinations.