The National Air and Space Museum is one of the world's most popular museums. Its mission is to commemorate, educate, and inspire visitors by preserving and displaying aeronautical and spaceflight artifacts. The museum maintains the world's largest collection of historic aircraft and spacecraft. It is also a vital center for historical research on aviation and spaceflight and related science and technology, and home to the Center for Earth and Planetary Studies, which performs original research and outreach activities in planetary sciences.