The explosion was caused by O-ring failure. The parts were manufactured by Morton Thiokol. Prior to launch, two of their engineers begged Morton Thiokol and NASA to stop the launch because it was too cold and O-ring failure was more probable. They were told to shut up. One of the engineers is now 89 years old and still carries the guilt.
Space travel is not for the risk-averse. The mortality rate is about the same as climbing Everest.
That poor man.