The Stratospheric Observatory for Infrared Astronomy (SOFIA) is a joint German-US space science project. Carrying a 2.7-metre telescope inside a modified Boeing 747SP, the airborne observatory performs astronomical observations in the infrared and submillimetre wavelengths, high above the disturbance of Earth's atmosphere. The scientific objective is to understand the development of galaxies and the formation and evolution of stars and planetary systems from interstellar clouds of gas and dust.