The first metal 3D printer to operate aboard the International Space Station seen during ground testing, producing an ESA-design sample part. Its development led by ESA, this Metal 3D Printer aims to prove that metal 3D printing can be performed in weightless conditions, opening the way to a future in-space manufacturing capability where astronauts far from Earth can produce whatever tools or spare parts they need. The print process will be supervised closely, allowing the development team to learn as much as they can. The sealed printer box is fitted with LED lighting, a camera and precision sensors so ground operators can follow the progress of the printing down to each new deposition layer, and the printing can be adjusted if any defects arise.