Seventy-three seconds into its launch, the Space Shuttle Challenger disintegrated, killing everyone on board. Investigators concluded that an O-ring—a rubber seal located in the right booster engine—had failed due to cold weather at the time of launch, causing a chain reaction that led to the orbiter’s ultimate disintegration. The tragic event was captured on film, and many children viewed the launch live because schoolteacher Christa McAuliffe was on board. Why was she on the shuttle? Discuss