HST is one of NASA's most successful and long-lasting science missions. A space-based astronomical observing facility, launched in April 1990 and orbiting the Earth at an altitude of 610 km. It consists of a 2.4-m telescope and four complementary scientific instruments, is roughly cylindrical, and is 13 m long and 4 m in diameter, with two large solar panels. The HST is a cooperative programme between NASA and the European Space Agency (ESA).
Before the US$2.5 billion HST could reach its full potential, a flaw in the shape of its main mirror had to be corrected in 1993 by astronauts aboard the space shuttle Endeavour. By October 2003, the telescope had produced about 500 000 images, and had been serviced by astronauts four times. NASA announced in 2004 that it would cancel future servicing of Hubble, which will cause it to cease operating in a few years. This was a financial decision, following US president George W. Bush's announcement in January 2004 that astronauts will be returned to the Moon in 2020.
To date, HST has made more than 1.3 million observations. It has beamed hundreds of thousands of images back to Earth, shedding light on many of the great mysteries of astronomy. Its gaze has helped determine the age of the universe, the identity of quasars, and the existence of dark energy. Among its many discoveries, Hubble has revealed the age of the Universe to be about 13 to 14 billion years, much more accurate than the old range of anywhere from 10 to 20 billion years. In December 1995 the HST was trained on an ‘empty’ area of sky near the Plough, now termed the Hubble Deep Field. In 2002 an Advanced Camera for Surveys (ACS) was installed, and in 2004 it revealed the deepest view ever of the universe, showing galaxies formed shortly (700 million years) after the Big Bang. It discovered that gamma-ray bursts occur in far distant galaxies when massive stars collapse. In August 2017 it contributed critical observations of a never-before-seen hypernova which was the source of gravitational waves.
http://hubble.stsci.edu/ Everything you could ever want to know about the Hubble Space Telescope. This attractive site features a showcase of the very best of Hubble's images and the latest news on the telescope, as well as an illustrated guide to the spacecraft, its instruments, and its optical system.