The U.S. space shuttle Atlantis and its crew have moved in close to the Hubble Space Telescope to begin an ambitious repair mission.
Atlantis is preparing to use its robot arm (12:54 PM EDT) to grab the orbiting telescope and position it in the shuttle's open cargo bay.
The Atlantis crew plans to make five spacewalks, beginning Thursday, to install new cameras and equipment on the telescope. The astronauts will also repair some broken science instruments during their 11-day mission.
The work is intended to keep Hubble in operation for at least five more years. It has been in orbit since 1990, photographing celestial bodies with a clarity that cannot be matched by telescopes on Earth.
The U.S. space agency, NASA, estimates the repair mission, the fifth and final space flight to service Hubble, will cost $1 billion.
On Tuesday, NASA officials said astronauts aboard Atlantis discovered a 53-centimeter stretch of nicks on the spacecraft's heat-resistant tiles, but that the damage does not appear to be serious. They say the nicks likely were caused by debris that came off the shuttle's fuel tank during liftoff on Monday.
Damage to the shuttle during blastoff has been a worry for NASA. In 2003, damage to the heat shield caused the shuttle Columbia to disintegrate as it re-entered Earth's atmosphere, killing all seven astronauts on board.
Missions to the telescope can be riskier than missions to the International Space Station. The space station can support a stranded crew for up to three months, but astronauts traveling to Hubble only have the supplies they carry with them.
NASA says the space shuttle Endeavour will sit standby on a launch pad in case the Atlantis crew has to be rescued.
Some information for this report was provided by AFP, AP and Reuters.