Hubble Space Telescope data, while the Goddard Space Flight Center controls the spacecraft. 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 spherical aberration, compromising the telescope's capabilities. The optics were corrected to their intended quality by a servicing mission in 1993. Hubble is the only telescope designed to be serviced in space by astronauts. After launch by in 1990, five subsequent Space Shuttle missions
Hubble Space Telescope 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 , and could last until 2030–2040. Its successor, the James Webb Space Telescope (JWST), is scheduled for launch in March 2021. In 1923, Hermann Oberth—considered a father of modern rocketry, along with Robert H. Goddard and Konstantin Tsiolkovsky—published "" ("The Rocket into Planetary Space"), which mentioned how a telescope could