PHOTOS: NASA's Darkest Moments

NASA marks anniversaries of Challenger, Columbia, Apollo 1 accidents.

PHOTOS: Challenger, Columbia, Apollo: NASA's Darkest Moments

Space Disasters
Space Disasters
Space Disasters
Space Disasters
Space Disasters
Space Disasters
Space Disasters
Space Disasters
Space Disasters
Space Disasters
Space Disasters
Apollo 13, in April 1970, was one accident that ended in triumph. A damaged oxygen tank exploded as the astronauts approached the moon -- but through luck, ingenuity and endurance, the astronauts rode their crippled ship safely home. (NASA)
ABC News on Facebook