X-ray telescope onboard Astro-E: optical design and fabrication of thin foil mirrors

X-ray telescopes (XRT 's) of nested thin foil mirrors are developed for Ast ro-E, the fifth Japanese x-ray astronomy satellite. Although the launch was not successful, the design concept, fabrication, and alignment procedure a re summarized. The main Purpose of the Astro-E XRT is to collect hard x ray s up to 10 keV with high efficiency and to provide medium spatial resolutio n in limited weight and volume. Compared with the previous mission, Advance d Satellite for Cosmology and Astrophysics (ASCA), a slightly longer focal length of 4.5-4.75 m and a larger diameter of 40 cm yields an effective are a of 1750 cm(2) at 8 keV with five telescopes. The image quality is also im proved to 2-arc min half-power diameter by introduction of a replication pr ocess. Platinum is used instead of gold for the reflectors of one of the fi ve telescopes to enhance the high-energy response. The fabrication and alig nment procedure is also summarized. Several methods for improvement are sug gested for the reflight Astro-E II mission and for other future missions. P reflight calibration results will be described in a forthcoming second pape r, and a detailed study of images will be presented in a third paper. (C) 2 001 Optical Society of America.