NAME_1: "The NAME_2 Space Telescope (often referred to as HST or NAME_2) is a space telescope that was launched into low Earth orbit in 1990 and remains in operation. It was not the first space telescope, but it is one of the largest and most versatile, renowned both as a vital research tool and as a public relations boon for astronomy. The NAME_2 telescope is named after astronomer NAME_3 and is one of NASA's Great Observatories. The Space Telescope Science Institute (STScI) selects NAME_2's targets and processes the resulting data, while the Goddard Space Flight Center (GSFC) controls the spacecraft.
NAME_2 features a 2.4 m (7 ft 10 in) mirror, and its five main instruments observe in the ultraviolet, visible, and near-infrared regions of the electromagnetic spectrum. NAME_2's orbit outside the distortion of Earth's atmosphere allows it to capture extremely high-resolution images with substantially lower background light than ground-based telescopes. It has recorded some of the most detailed visible light images, allowing a deep view into space. Many NAME_2 observations have led to breakthroughs in astrophysics, such as determining the rate of expansion of the universe.
Space telescopes were proposed as early as 1923, and the NAME_2 telescope was funded and built in the 1970s by the United States space agency NASA with contributions from the European Space Agency. Its intended launch was in 1983, but the project was beset by technical delays, budget problems, and the 1986 Challenger disaster. NAME_2 was finally launched in 1990, but its main mirror had been ground incorrectly, resulting in spherical aberration that compromised the telescope's capabilities. The optics were corrected to their intended quality by a servicing mission in 1993.
NAME_2 is the only telescope designed to be maintained in space by astronauts. Five Space Shuttle missions have 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), but after NASA administrator NAME_4 approved it, the servicing mission was completed in 2009. NAME_2 completed 30 years of operation in April 2020[1] and is predicted to last until 2030–2040.