Challenger Space Shuttle

The world has witnessed a lot of accidents out of which the explosion of the challenger space shuttle,is a notable one.This accident took place on 28th January 1986 ,due to the failure of the solid boosters.During the preflight experiments,the thiokol engineers had noticed a black soot and grease on the outside of the boosters due to the leak of the hot gases blown through the O rings.So they redesigned the O rings but unfortunately they were not ready during the time of flight in1986. Also the American govt. urged NASA to launch the challenger shuttle in 1986 itself,before the launch of the Russians.

This was the main reason for the failure of challenger.During the time of launch.the cameras noticed a puff of smoke coming out from the field joints as soon as the solid boosters were ignited.But the O rings were not properly positioned due to extremely cold conditions. So the joints had opened and the hot gases escaped from the solid boosters.This led to the ignition of the
liquid propellant making the shuttle explode.