Columbia Aerospace is one of America's largest corporations. Its major products are satellites, spacecraft, fusion drives, and high-energy lasers (both weapons and launching). It is one of the world's largest space-defense contractors, with subsidiaries involved in a wide range of military activity. It has built most of the USAF's combat spacecraft since the 2050s, when it absorbed the last of the 20th-century aerospace giants. Columbia Aerospace's headquarters is at Columbia Station in Earth orbit, and it also manages Quito Spaceport, the system's busiest aerospace launch complex.