Another possible GI question about what is an astronaut?
An astronaut is someone who flies aircraft higher than 50 miles above sealevel.
The term astronaut also has a meaning that is not connected with NASA activities. In the 1960's, the United States Department of Defense awarded the rating of astronaut to military and civilian pilots who flew aircraft higher than 50 miles (80 kilometers). Seven test pilots received this rating for flights in the X-15 rocket plane. Flights of the X-15 ended in 1968.