For an astronaut, what type of knowledge required?

A lot.

So, What Does It Take to Be an Astronaut?

Astronaut requirements have changed with NASA's goals and missions. A pilot's license and engineering experience is still one route a person could take to becoming an astronaut, but it’s no longer the only one. Today, to be considered for an astronaut position, U.S. citizens must meet the following qualifications:

A bachelor's degree in engineering, biological science, physical science, computer science or mathematics.
At least three years of related professional experience obtained after degree completion OR at least 1,000 hours pilot-in-command time on jet aircraft.
The ability to pass the NASA long-duration astronaut physical. Distant and near visual acuity must be correctable to 20/20 for each eye. The use of glasses is acceptable.

Astronaut candidates must also have skills in leadership, teamwork and communications.

NASA's Astronaut Selection Board reviews the applications (a record-breaking 18,300 in 2016) and assesses each candidate's qualifications. The board then invites about 120 of the most highly qualified candidates to NASA's Johnson Space Center in Houston, Texas, for interviews. Of those interviewed, about half are invited back for a second round. Once the final astronauts are selected, they must complete a two-year training period.

With NASA's plans for the future of exploration, new astronauts will fly farther into space than ever before on lunar missions and may be the first to fly on to Mars.