What Was Changed in Future Missions?

In 1991 the shuttle Endeavor joined the fleet to replace the Challenger. 

The O ring design was re-looked at, and was changed to guarantee a safer flight.  The O ring on the challenger malfunctioned under thermal distress (it over heated).  The size of the O ring was approximately one inch.  

 


The addition of a crew bail-out system was also added. NASA implemented stricter safety rules and regulations as well.