near infrared. The telescope is named after the astronomerEdwin Hubble. Although not the first space telescope, Hubble is one of the largest and most versatile, and is well known as both a vital research tool and a public relations boon for astronomy. The HST was built by the United States space agency NASA, with contributions from the European Space Agency, and is operated by the Space Telescope Science Institute. 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
. When finally launched in 1990, scientists found that the main mirror had been ground incorrectly, compromising the telescope's capabilities. The telescope was restored to its intended quality by a servicing mission in 1993.