This is an exciting day for astronomy as the Space Shuttle Atlantis and its crew of seven astronauts prepare to launch into orbit and rendezvous with the Hubble Space Telescope. Hubble has been in orbit for 19 years now, sending back a constant stream of images and data which have revolutionized almost every field of astronomy. But almost two decades in space have taken their toll and the telescope is in desperate need of refurbishment.
Having matched orbits with Hubble 560km above the Earth, Atlantis will grasp the bus-sized telescope with its robotic arm and pull it into the shuttle's cargo bay where the astronauts can carry out their repairs and upgrades. This will be no easy task and will require no less than five gruelling spacewalks - uncomfortable hours spent in the confines of a spacesuit trying to manoeuvre phone-booth sized pieces of equipment into position and perform precision tasks whilst wearing thick protective gloves.
The shuttle crew have been in intensive training for this mission for months but even so the trip is not without personal risk. Since the tragic loss of the shuttle Columbia in 2003 NASA has only allowed its shuttles to venture into orbits from which they could reach the International Space Station in an emergency. Hubble is 200km higher than the ISS and the shuttle doesn't carry enough fuel to reach it should anything go wrong but, in recognition of Hubble's scientific importance, NASA have waived this rule for the current mission. Instead Atlantis' sister craft Endeavour will be waiting on the launch pad in case a rescue mission is needed.
If all goes well, Hubble will have two brand new state-of-the-art instruments fitted, bringing it bang up to date with 21st Century technology and expanding its science capabilities enormously. The Atlantis crew will also repair three malfunctioning instruments and replace other old and failing equipment. The refurbished Hubble should enjoy a healthy old age lasting well into the next decade and keeping astronomers busy until the launch of its successor, the James Webb Space Telescope, in 2013.