Without doubt the Hubble Space Telescope is one of the most important telescopes ever built. Its clear view of the cosmos, above the turbulent and distorting atmosphere, has changed our understanding of the Universe in which we live. Its science is remarkable, its images iconic and it had much more to give. So why is it being abandoned? Few were expecting such an announcement about the demise of Hubble. Just a few weeks ago Steven Beckwith, the director of Hubble's home institution, the Space Telescope Science Institute in Maryland, told BBC News Online that he was looking forward to the next servicing mission and the upgrade Hubble would receive. Mr Beckwith said that Hubble was working more efficiently than when it was new and could get even better. With Hubble's replacement - the James Webb Telescope - not due in orbit until 2012 at the earliest, he hoped that Hubble could survive until the handover. So what happened? Why is the US space agency (Nasa) abandoning one of the most productive scientific instruments of all time? The main reason is safety. It is said that the decision was made solely by Nasa's chief, Sean O'Keefe, and that it was not related to President George Bush's new space plan for a return to the Moon and missions to Mars. Money was not an issue.