Two U.S. astronauts stepped out on the last spacewalk of the shuttle era Tuesday at the International Space Station, where Atlantis is docked on the final mission of the 30-year U.S. program.
Two U.S. astronauts stepped out on the last spacewalk of the shuttle era Tuesday at the International Space Station, where Atlantis is docked on the final mission of the 30-year U.S. program.