http://er.jsc.nasa.gov/seh/explode.html http://er.jsc.nasa.gov/seh/explode.html http://er.jsc.nasa.gov/seh/explode.html fitted to the field joint thwarted CHALLENGER EXPLOSION – NASA http://er.jsc.nasa.gov/seh/explode.html http://er.jsc.nasa.gov/seh/explode.html http://er.jsc.nasa.gov/seh/explode.html The redesign added a third O-ring http://er.jsc.nasa.gov/seh/explode.html http://er.jsc.nasa.gov/seh/explode.html Challenger Explosion at Nasa http://er.jsc.nasa.gov/seh/explode.html http://er.jsc.nasa.gov/seh/explode.html faulty O-rings CHALLENGER EXPLOSION – NASA