Challenger exploded when an O-ring associated with the right solid rocket booster failed due to cold temperatures during launch. The failure caused the shuttle to break apart 73 seconds after liftoff.
Unseasonably cold January temperatures caused a rocket booster O-ring to become brittle. When Challenger's O-ring failed, pressurized gas from the motor escaped and affected the fuel tank. After this, the right solid rocket booster separated, and the fuel tank failed. The orbiter disintegrated soon after this failure.
Search and rescue operations later recovered the crew compartment from the ocean. The crew compartment had no escape mechanism, but investigators discovered that personal air packs were used, and some of the control switches were moved out of their customary position. The findings indicated that some of the crew were still alive and conscious after the disintegration. The crew compartment hit the ocean at a speed just over 200 mph; the impact with the water was not survivable.
The United States' space program was halted for 32 months after the Challenger disaster while a commission formed to investigate the tragedy and make corrections for the future. The investigation discovered that the manufacturer of the O-ring, Morton Thiokol, was aware of the flaw but did not act on the information. NASA also was warned of the potential for failure, but ignored the warnings.