The ship itself broke apart due to aerodynamic forces—it basically plunged toward the ocean at the speed of sound. The shuttle was not designed to let the crew escape in case of an in-flight emergency. All those aboard died, including social studies teacher Christa McAuliffe. There are hints that the crew remained conscious until the shuttle hit the Atlantic Ocean.
“The fundamental problem was that SRBs are dangerous because they are not engines. Think of a rocket booster as an elongated powder keg with a nozzle at the bottom. Once you light it, you cannot stop its burn. You cannot throttle it down in case of malfunction. Yet SRBs were chosen because they offered a more economical solution to meet the program's budgetary constraints.”
“Solid boosters are often used in unmanned rocket launches because they are cheap to manufacture and provide high levels of thrust without a corresponding increase in complexity. They are not typically used in manned spacecraft because they produce a very rough ride and cannot be shut down.”