Event:
William Dana reaches 80 km (last high-altitude X-15 flight)
More Notable Events on August 21:
1993 NASA loses contact with Mars Observer
1989 Voyager 2 begins a flyby of planet Neptune
1968 Democratic Convention opens in Chicago
1968 Warsaw Pact forces enter Czechoslovakia to end reform movement
1897 Oldsmobile begins operation as a General Motors Corp division