The four astronauts on NASA’s mission flew deeper into space on Monday than any humans before them, as they cruised through a rare flyby of the shadowed far side of the moon that revealed a lunar surface under cosmic bombardment. The six-hour flyby, which swooped to within 6,550 kilometers of the lunar surface, came six days into a spaceflight marking the world's first voyage of astronauts to the vicinity of the moon since NASA’s Cold War-era Apollo missions more than half a century ago.