Hubble Space Telescope above the Earth.

Hubble Space Telescope above the Earth. The Hubble Space Telescope (HST) was put into orbit from the Space Shuttle Discovery, mission STS-31, on 24 April 1990. The HST was designed to see seven times further into space than had been possible before, without the distortion caused by the Earth's atmosphere. Problems with its giant mirror meant that it did not initially work as well as expected. Corrective optics were installed in 1993, greatly improving the telescope's performance, enabling it to view the Universe in unprecedented detail. (Photo by Ann Ronan Pictures/Print Collector/Getty Images)