Building in space means creating a habitat for people and for the cohabitation of people. In the short lecture, two space architecture projects will be described in more detail: The international housing module of the Lunar Gateway space station, to be built in lunar orbit starting in 2026, and the Regolight project, which uses the lunar resources of sunlight and lunar sand to 3D print them into radiation-shielding domes for an astronaut crew on the lunar surface.