The Array of Low Energy X-ray Imaging Sensors (ALEXIS, also known as P89-1B, COSPAR 1993-026A, SATCAT 22638) X-ray telescope featured curved mirrors whose multilayer coatings reflected and focused low-energy X-rays or extreme ultraviolet (EUV) light the way optical telescopes focus visible light. The satellite and payloads were funded by the United States Department of Energy and built by Los Alamos National Laboratory (LANL) in collaboration with Sandia National Laboratories and the University of California-Space Sciences Lab. The satellite bus was built by AeroAstro, Inc. of Herndon, VA. The Launch was provided by the United States Air Force Space Test Program on a Pegasus Booster on April 25, 1993. The mission was entirely controlled from a small groundstation at LANL. Features ALEXIS scanned half the sky with its three paired sets of EUV telescopes, although it could not locate any events with high resolution. Ground-based optical astronomers could look for visual counterparts to the EUV transients seen by ALEXIS by comparing observations made at two different times. Large telescopes, with their small fields of view, cannot quickly scan a large enough piece of the sky to effectively observe transients seen by ALEXIS, but amateur equipment is well suited to the task. Participants in the ALEXIS project combed the ALEXIS data for the coordinates of a likely current transient, then trained their telescopes and observe the area. There were six EUV telescopes which were arranged in three co-aligned pairs which cover three overlapping 33° fields-of-view. At each rotation of the satellite, ALEXIS monitored the entire anti-solar hemisphere. Each telescope consisted of a spherical mirror with a Mo-Si layered synthetic microstructure (LSM) or Multilayer coating, a curved profile microchannel plate detector located at the telescope's prime focus, a UV background-rejecting filter, electron rejecting magnets at the telescope aperture, and image processing readout electronics. The geometric collecting area of each telescope was about 25 cm2, with spherical aberration limiting resolution to about 0.25°s. Analysis of the pre-flight x-ray throughput calibration data indicated that the peak on-axis effective collecting area for each telescope's response function ranges from 0.25 to 0.05 cm2. The peak area-solid angle product response function of each telescope ranged from 0.04 to 0.015 cm2-sr. The spacing of the molybdenum and silicon layers on each telescope's mirror was the primary determinant of the telescope's photon energy response function. The ALEXIS multilayer mirrors also employed a "wavetrap" feature to significantly reduce the mirror's reflectance