Aerospace engineering is the branch of engineering behin the design, construction and science of aircraft and spacecraft. Aerospace engineering has broken into two major branches, aeronautical engineering and astronautical engineering. The former deals with craft that stay within Earth's atmosphere, and the latter deals with craft that operate outside of Earth's atmosphere. While "aeronautical" was the original term, the broader "aerospace" has superseded it in usage, as flight technology advanced to include craft operating in outer space.