Endeavour astronauts begin orbital walk in space

Two crew members of the space shuttle Endeavour began their third and final spacewalk of the mission this evening which will see them connect power cables and open the shutters on earth's orbital bay window.

Tonight's spacewalk began at 9:15 pm EST, as the International Space Station flew 220 miles high above the southern Pacific Ocean.

Astronuts Robert Behnken and Nicholas Patrick left the Quest airlock minutes later to begin their six and one-half hour orbital walk in space.

Behnken began work by opening up a second coolant loop which will flow ammonia into the new Tranquility node.

Later tonight, the pair will remove the protective covers from the windows of the newly installed cupola observation module. Once the covers are removed, station crews will have a panaromic 360-degree field view of the earth and the space beyond as they sail upon the ocean of space.