The Hubble Space Telescope (HST; also known colloquially as "the Hubble" or just "Hubble") is a space telescope that was carried into orbit around the Earth by the Space Shuttle Discovery in April 1990. It is named for the American astronomer Edwin Hubble. Hubble's position outside the Earth's atmosphere allows it to take extremely sharp images and, although not the first space telescope to be deployed, Hubble has become one of the most important instruments in the history of astronomy. Hubble's Ultra Deep Field image, for instance, is the most detailed visible-light image of the universe's most distant objects ever made. Many observations made using the telescope have led to breakthroughs in astrophysics. The construction and launch of the Hubble was beset by delays and budget problems. Then, soon after its 1990 launch, it was found that the main mirror suffered from spherical aberration due to faulty quality control during its manufacturing, severely compromising the telescope's...