for He II 304 Angstrom geocoronal radiation which can be a significant background source for space borne EUV telescopes. These mirrors, produced by Ovonyx, Inc., were highly curved yet have been shown to have very uniform multilayer coatings and hence have very uniform EUV reflecting properties over their entire surfaces. The efforts in designing, producing and calibrating the ALEXIS telescope mirrors have been previously described in Smith et al., 1990. ALEXIS weighed 100 pounds, used 45 watts, and produced 10 kilobits/second of data. Position and time of arrival were recorded for each detected photon. ALEXIS was always in a survey-monitor mode, with no individual source pointings. It was suited for simultaneous observations with ground-based observers who prefer to observe sources at opposition. Coordinated observations needed not be arranged before the fact, because most sources in the anti-Sun hemisphere were observed and archived. ALEXIS was tracked from a single ground station in Los Alamos. Between ground station passes, data was stored in an on-board solid state memory of 78 Megabytes. ALEXIS, with its wide fields-of-view and well-defined wavelength bands, complemented the scanners on NASA's Extreme Ultraviolet Explorer (EUVE) and the ROSAT EUV Wide Field Camera (WFC), which were sensitive, narrow field-of-view, broad-band survey experiments. ALEXIS's results also highly complemented the data from EUVE's spectroscopy instrument. ALEXIS's scientific goals were to: Map the diffuse background in three emission line bands with the highest angular resolution to date, Perform a narrow-band survey of point sources, Search for transient phenomena in the ultrasoft X-ray band, and Provide synoptic monitoring of variable ultrasoft X-ray sources such as cataclysmic variables and flare stars. End of mission On 29 April 2005, after 12 years in orbit, the ALEXIS satellite reached the end of its mission and was decommissioned. The satellite exceeded expectations by operating well past its one year design life. See also 1993 in spaceflight References Spacecraft launched in 1993 Derelict satellites orbiting Earth Space telescopes X-ray telescopes Spacecraft launched by Pegasus rockets