Gazing into the MgF_2 ball: UV astronomy for the 3rd millenium

Abstract

I examine possible futures for UV astronomy, in view of the past history and collected knowledge of the UV sky through various missions since the early days of Space Astronomy. The last all-sky survey has been by TD-1 in the early 1970s, resulting in reasonable mapping of discrete sources brighter than ~9th mag (monochromatic, UV). Since TD-1, few advances were made in general knowledge of the UV through survey missions, but dedicated, single-object studies advanced mainly through the IUE spectroscopic results. Selected sky areas were surveyed to deeper magnitudes than by TD-1 with various balloon and rocket flights, Shuttle and MIR payloads, etc. The HST offered some UV capability with WFPC 1 and 2, FOC, and presently with STIS, but with small fields of view. The future of UV astronomy seems bleak, with only FUSE with any certainity of being flown and with the recent recommendation of the Dressler committee to emphasize NIR and interferometry into the next millenium. The community's hopes reside therefore with (a) better exploitation of existing data bases, (b) dual-usage missions, (c) piggy-back modern payloads, and (d) low cost alternatives such as long-duration balloon flights. These could demonstrate the advantage of a real UV sky survey mission, equivalent in the number of sources to the POSS I & II and ESO optical surveys.