The Far Ultraviolet Spectroscopic Explorer (FUSE) was launched on June 24, 1999. It was the scientific successor to the International Ultraviolet Explorer (IUE) and employed many new technologies, including the use of four mirror segments rather than a single primary mirror. FUSE was designed to study, among many other things, the distribution and composition of matter early in the universe, the dispersion of chemical elements throughout galaxies, and the properties of interstellar gas clouds out of which stars and solar systems form. After a successful three-year primary mission, FUSE embarked on a longer secondary mission that achieved many more scientific milestones, including discoveries about deuterium in the distant universe and observations of hundreds of stars in the Magellanic Clouds. FUSE was decommissioned on October 18, 2007.