<P> The HST was built by the United States space agency NASA, with contributions from the European Space Agency . The Space Telescope Science Institute (STScI) selects Hubble's targets and processes the resulting data, while the Goddard Space Flight Center controls the spacecraft . </P> <P> Space telescopes were proposed as early as 1923 . Hubble was funded in the 1970s, with a proposed launch in 1983, but the project was beset by technical delays, budget problems, and the Challenger disaster (1986). When finally launched in 1990, Hubble's main mirror was found to have been ground incorrectly, compromising the telescope's capabilities . The optics were corrected to their intended quality by a servicing mission in 1993 . </P> <P> Hubble is the only telescope designed to be serviced in space by astronauts . After launch by Space Shuttle Discovery in 1990, five subsequent Space Shuttle missions repaired, upgraded, and replaced systems on the telescope, including all five of the main instruments . The fifth mission was initially canceled on safety grounds following the Columbia disaster (2003). However, after spirited public discussion, NASA administrator Mike Griffin approved the fifth servicing mission, completed in 2009 . The telescope is operating as of 2018, and could last until 2030--2040 . Its scientific successor, the James Webb Space Telescope (JWST), is scheduled for launch in March 2021 . </P> <P> In 1923, Hermann Oberth--considered a father of modern rocketry, along with Robert H. Goddard and Konstantin Tsiolkovsky--published Die Rakete zu den Planetenräumen ("The Rocket into Planetary Space"), which mentioned how a telescope could be propelled into Earth orbit by a rocket . </P>

When was the hubble space telescope launched by space shuttle discovery