Those qualifications are pretty strict. In order to apply, you have to:
- Be a US citizen
- Have at least a Bachelors' degree in "engineering, biological science, physical science, computer science, or mathematics" (nursing, many social sciences, and some psychology degrees don't make the cut)
- Have 3 years of professional experience in your field (teaching is ok), or have 1, 000 hours of "pilot in command" time on a jet
- Be able to see in 20/20, or have glasses that let you see in 20/20
- Be between 5 feet 2 inches and 6 feet 3 inches tall, so you can fit into the space suit
NASA is hiring more astronauts because they're planning a lot of missions in the coming years, including trips that will pave the way to landing a person on Mars, NASA's current long-term goal for crewed missions.