Future ultraviolet experiments, including FUSE/COLUMBUS

Several new facilities for ultraviolet astronomy are under construction or study for launch within the coming decade. These include the Hubble Space Telescope to be launched in 1986 with instruments for spectroscopy, imaging, and photopolarimetry in the ultraviolet; the ASTRO Spacelab payload, also to be launched in 1986 with a similar range of instrumentation; STARLAB, a combined Canadian, Australian and U.S. mission concentrating primarily on imagery; and the Far Ultraviolet Spectroscopic Explorer (FUSE), which was renamed COLUMBUS. COLUMBUS is currently under study by NASA and ESA as a future joint mission for spectroscopic studies of astrophysical plasmas covering a temperature range from approximately 10 to the 3rd power to approximately 10 to the 7th power k. In order to achieve this objective, the optics should be optimized for wavelengths below 1200 Angstroms, with a total wavelength range from approximately 2000 to approximately 100 Angstroms. The operational concept will be based on experience with IUE, but changes in communications techniques since IUE was designed suggest some interesting new approaches to observing.