Fifty years after a mighty rocket set off from Florida carrying the first humans to the Moon, a veteran of the Apollo 11 crew returned to its fabled launch pad Tuesday to commemorate "one giant leap" that became a defining moment in human history. "We crew felt the weight of the world on our shoulders, we knew that everyone would be looking at us, friend or foe," command module pilot Michael Collins said from the Kennedy Space Center. Collins remained in lunar orbit in the command module Columbia, their only means of returning to Earth.