Launched in 1990 as 'our window on the universe', the Hubble Space Telescope has for the past quarter century been providing us with astonishing images of space that have led to numerous scientific breakthroughs.
To celebrate it's 25th anniversary, here's a quick explainer on everything you need to know about Nasa's famous space telescope.
Nasa launched Hubble Space Telescope, a giant space telescope, into low Earth orbit on 24 April 1990.
The telescope is named after American astronomer Edwin Hubble.
When first launched, it was discovered Hubble's main mirror had been ground incorrectly, which stopped the telescope from functioning properly.
It was not until a servicing mission in 1993 that this was corrected.
Outside the distortion of Earth's atmosphere, Hubble can take better pictures than telescopes on Earth.
It has taken some of the most detailed and beautiful images of the universe.
Hubble's pictures have helped scientists guess the age and size of the universe. They now think it is about 13 or 14 billion years old.
The Hubble Space Telescope is still operating and may last until 2020.
Its successor, the James Webb Space Telescope, is due to be launched in 2018.