Starting on December 14, NASA will begin accepting applications for the astronaut class of 2015 (read more here: The last class had over 6,000 applications, but only 8 were selected. The process is a long one, involving references, medical exams & interviews for the 'highly qualified' candidates. Here are the qualifications:
  1. United States citizenship
  2. Bachelor's degree in a science, technology, engineering or math field
  3. Three years experience working or teaching in a scientific field OR 1,000 hours of flight time in command of a jet
  4. 20/20 vision (laser-corrected counts)
  5. Good blood pressure
  6. Height between 62 and 75 inches