Space shuttle Endeavour commander Mark Kelly addresses members of the media after he arrived at the Kennedy Space Center in Cape Canaveral, Fla., Thursday, May 12, 2011. Kelly will lead a crew of five other astronauts on a mission to the International Space Station. The astronauts for NASA's next-to-last space shuttle flight returned to Florida on Thursday for another try at launching to the International Space Station.(AP Photo/John Raoux)