To think that the launch was not obtainable was not considered; when looking back at the rest of their travels, one would initially think there would be no issue. Thus, the Challenger launch was seen as attainable. According to NASA, just after liftoff at .678 seconds into the flight, photographic data
show a strong puff of gray smoke was spurting from the vicinity of the
aft field joint on the right Solid Rocket Booster. combustion gas leak through the right Solid Rocket Motor aft field joint initiated at or shortly after ignition, resulting in the failure in the joint between the two lower segments of the right Solid Rocket Motor, thus, the luanch was not attainable.