This photograph shows the Hubble Space Telescope (HST) being assembled in the clean room of the Lockheed Missile and Space Company. This view was taken after the AFT shroud was placed over the Optical Telescope Assembly (OTA). The OTA contains two mirrors, primary and secondary, to collect and focus light from selected celestial objects. The HST is the first of NASA's great observatories and the most complex and sensitive optical telescope ever made. The purpose of the HST is to study the cosmos from a low-Earth orbit by placing the telescope in space, enabling astronomers to collect data that is free of the Earth's atmosphere. The HST was deployed from the Space Shuttle Discovery (STS-31 mission) into Earth orbit in April 1990. The Marshall Space Flight Center had overall responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Cornecticut, developed the optical system and guidance sensors. The Lockheed Missile and Space Company, Sunnyvale, California, produced the protective outer shroud and spacecraft systems, and assembled and tested the finished telescope.