English: This photograph shows the Hubble Space Telescope (HST) installed in the cargo bay of the Space Shuttle Orbiter Discovery for the STS-31 Mission at The Kennedy Space Center prior to launch on April 24, 1990. 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 Marshall Space Flight Center had overall responsibility for design, development, and construction of the HST. The Perkin-Elmer Corporation, in Danbury, Connecticut, developed the optical system and guidance sensors. The Lockheed Missiles and Space Company, Sunnyvale, California, produced the protective outer shroud and spacecraft systems, and assembled and tested the finished telescope.