What was the Challenger?

In 1982 Challenger became the second member of NASA's fleet of space shuttle orbiters. Because of the tragic ending of Challenger, it is probably recognized by more people worldwide than any other space shuttle. Challenger completed nine flights, the first in April 1983, before its explosion in 1986.
What Were Some of Challenger's Early Missions?

On its first flight, challenger carried a tracking and data relay satelliteinto space. Two months later, Challenger flew again. On the crew of this flight was Sally Ride, the first U.S. female astronaut in space. On board the third flight was Guion Bluford, the first African American astronaut in space. Challenger has also placed the European Spacelab, as well as, a number of military and scientific satellites into orbit.
What Happened on the last flight of Challenger?

What happened on the last flight of Challenger? Challenger's tenth flight was to be on January 28, 1986. This flight would have been the twenty-fifth of the four-shuttle fleet. The launch had already been delayed four times before that cold morning at Cape Canaveral. Seventy-three seconds after lift-off Challenger exploded, killing all seven people on board.
Why was so much attention focused on the tenth launch?

This shuttle flight had been highly publicized because it carried the first schoolteacher into space, Chrisa McAuliffe. McAuliffe had been picked from a pool of eleven thousand applicants. She had been scheduled to broadcast a numbrer of lessons while in orbit directly into schools. The other six astronauts on board Challenger reflected a cross-section of American popuace in terms of race, gender, home state, and religion. Millions of people around the world who tuned in to watch the televised lift-off became witness to the tragedy.
What caused the Challenger tragedy?

NASA officals found that the Challenger accident had been caused by a leak in one of the two solid rocket boosters that ignite the main fuel tank, the result of a faulty rubberized seal called an "O-ring".