The Challenger Disaster
On January 28, 1986, the\xa0NASA\xa0shuttle orbiter\xa0mission\xa0STS-51-L\xa0and the tenth flight of\xa0Space Shuttle\xa0Challenger\xa0(OV-99) broke apart 73 seconds into its flight, killing all seven crew members, which consisted of five NASA\xa0astronauts\xa0and two\xa0payload specialists. The spacecraft disintegrated over the\xa0Atlantic Ocean, off the coast of\xa0Cape Canaveral,\xa0Florida, at 11:39\xa0EST(16:39\xa0UTC). Disintegration of the vehicle began after an\xa0O-ring\xa0seal in its right\xa0solid rocket booster\xa0(SRB) failed at liftoff. The O-ring was not designed to fly under unusually cold conditions as in this launch. Its failure caused a breach in the SRB joint it sealed, allowing pressurized burning gas from within the solid rocket motor to reach the outside and impinge upon the adjacent SRB aft field joint attachment hardware and\xa0external fuel tank. This led to the separation of the right-hand SRB's aft field joint attachment and the\xa0structural failure\xa0of the external tank.\xa0Aerodynamicforces broke up the orbiter.