article_snippet.sent: Hubble was launched on 24 April 1990 aboard Space Shuttle Discovery.
article_snippet.sent: Despite a shaky start, when Hubble primary mirror was ground to the wrong shape, Hubble soon began returning fantastic images of the distant universe, to the delight of scientists and the public alike on Earth.
article_snippet.sent: Hubble has completely transformed our view of the universe,' said John Grunsfeld, astronaut and associate administrator of Nasa's Science Mission Directorate. '
article_snippet.sent: Hubble's near-infrared vision allows astronomers to identify its stars .
article_snippet.sent: Learning about the life cycle of stars was one of the reasons Hubble was built.
article_snippet.sent: By operating above distortions and blocking effects of Earth's atmosphere, astronomers hoped to look farther back in time, at generations of stars and galaxies that formed closer to the Big Bang, some 13.7 billion years ago.
article_snippet.sent: But the mission almost start in disaster, when Nasa discovered a manufacturing flaw in the telescope's 7.9ft (2.4-meter) diameter mirror.
article_snippet.sent: Corrective optics, installed by space-walking astronauts, saved the day in 1993, the first of five servicing calls by Space Shuttle crews. '
article_snippet.sent: We never thought it would last this long,' said Nasa administrator and former astronaut Charlie Bolden, the pilot on the mission.
article_snippet.sent: In Nasa quarter-century in orbit, Nasa has transformed our understanding of our solar system and beyond, and helped our find our place among the stars .
article_snippet.sent: Many of the telescope's most important discoveries turned out to be in areas that didn't even exist when it was launched.
article_snippet.sent: Hubble's observations of a particular kind of exploded star helped astronomers realise that the pace of the universe's expansion is ramping up, propelled by some unknown force referred to as 'dark energy.'
article_snippet.sent: Hubble also has imaged a planet beyond the solar system and scanned other planets' atmospheres for telltale chemical fingerprints.
article_snippet.sent: The first so-called exoplanet was discovered in 1992, two years after Hubble's launch. '
article_snippet.sent: Hubble has fundamentally changed our human understanding of Nasa universe,' Bolden said.