The six astronauts on Atlantis' flight to the International Space Station include two former football players as well as several Gulf War veterans.

Describing Apollo 11 astronauts as the "three genuine American heroes", US President Barack Obama, honouring them at the White House, said their exploration sparked innovation and creativity back on earth.

Three of six stabilizing gyros are kaput. A data router failed, and a backup had to take over. The telescope is getting slower about latching onto guide stars. The batteries are running down. And the shiny exterior has been torn up by countless collisions with tiny particles.Yet, despite the battering and the ravages of old age, the Hubble Space Telescope is still 500 million times as sensitive as the human eye, and astronomers say its best days may yet be ahead.