Shuttle Orbiter Discovery History:
Discovery has completed more than 30 successful missions, surpassing the number of flights made by any other orbiter in NASA's fleet. Just like all of the orbiters, it has undergone some major modifications over the years. The most recent began in 2002 and was the first carried out at Kennedy. It provided 99 upgrades and 88 special tests, including new changes to make it safer for flight.
Military Model Planes 32/51