Far Ultraviolet Spectroscopic Explorer (FUSE, Explorer 77, and MIDEX-0) represented the next generation, high-orbit, ultraviolet space observatory covering the wavelength range of 90.5–119.5 nanometre (nm) of the NASA operated by the Johns Hopkins University Applied Physics Laboratory. FUSE was launched on a Delta II launch vehicle on 24 June 1999, at 15:44:00 UTC, as a part of NASA's Origins Program. FUSE detected light in the far ultraviolet portion of the electromagnetic spectrum, which is mostly unobservable by other telescopes. Its primary mission was to characterize universal deuterium in an effort to learn about the stellar processing times of deuterium left over from the Big Bang. FUSE resides in a low Earth orbit, approximately in altitude, with an inclination of 24.98° and a 99.80 minutes orbital period. Its Explorer program designation is Explorer 77. Mission The primary objective of FUSE was to use high-resolution spectroscopy at far ultraviolet wavelengths to study the origin and evolution of the lightest elements (hydrogen and deuterium) created shortly after the Big Bang, and the forces and processes involved in the evolution of galaxies, stars and planetary systems. The spacecraft was launched as a joint NASA-Canada–France project. Only one previous mission, Copernicus (OAO-3), has given this far-ultraviolet region of the electromagnetic spectrum. However, FUSE will provide sensitivity some ten thousand times greater than Copernicus. FUSE primary and extended missions The first 3.5 years of FUSE operations were dubbed the Primary Mission. During this period, the observing time on FUSE was shared roughly 50–50 between the FUSE science team and a host of Guest investigators, astronomers from around the world selected by NASA to participate in the FUSE program. Starting 1 April 2003, the FUSE project entered an extended phase of operations which lasted until mid-2007. With funding from NASA, the FUSE satellite continued to be operated as an observatory for the broad astronomical community, with 100% of on-orbit observing time selected by NASA peer review. Some 29 million seconds of science data were obtained during the Primary Mission phase, and a total of nearly 65 million seconds of data were archived from the entire mission. The Extended Mission period presented a number of challenges, especially for satellite operations. Many procedures had to be automated, allowing the project to cut back on staffing and minimize operations costs. As one example, the Satellite Control Center was staffed around the clock during the Prime Mission but transitioned to a