Discovery astronauts begin spacewalk

Astronauts from the Space shuttle Discovery have begun the first spacewalk of their mission. They will install a new tank of ammonia coolant on the International Space Station.

The crew is also expected to replace one of the station's steering system's gyroscopes and work on the Canadian robot Dextre. The space shuttle carried an Italian-built cargo hauler filled with equipment, experiments, food and supplies for the space station. The space station is nearing completion after starting construction in 1998.

Astronauts from the Space shuttle Discovery have begun the first spacewalk of their mission.