WASHINGTON — So, you want to be an astronaut. Assuming you have a college degree, some scientific experience and meet all the physical criteria, you'll still have to undergo a psychological evaluation to determine if you have what it takes to fly on a NASA mission.

On Friday (Aug. 8), a panel of NASA psychologists described the rigorous process used to weed out people with mental disorders from the pool of potential astronauts and identify those best suited to the risky and isolated world of space travel. The panel spoke here at a meeting of the American Psychological Association.

"We're looking for the 'right stuff,' but we're also trying to get rid of people with the 'wrong stuff,'" said Kelley Slack, a psychologist at Wyle, an agency that contracts with NASA's Johnson Space Center in Houston, and a member of the astronaut selection panel. [7 Everyday Things that Happen Strangely In Space

The right stuff

Anyone with a college degree and some scientific experience can apply to be an astronaut. More than 6,000 people applied in 2013, but only eight individuals were selected. It takes almost two years from the time the job is advertised to the final selection of astronaut candidates, and in some cases, 10 years can go by before a newly selected astronaut makes his or her first spaceflight, Slack said.

"It's challenging to pick astronauts for a lot of reasons, primarily because we are predicting behavior so far in the future," Slack said. Also, the job the astronauts are selected for is probably not going to be the job they have by the time they fly.

The psychological selection process consists of two parts. The first round involves an initial set of interviews. In the second round, the applicants are assessed based on their suitability for the job, and interviews are conducted with a psychiatrist to determine any grounds for disqualification. The applicants also participate in field exercises at the Johnson Space Center to simulate some of the challenges of being in space. (Slack said she couldn't describe the specific exercises, for security reasons.)

The qualities NASA looks for in prospective astronauts are "pretty much what you'd expect from any individuals whose job it is to work very closely in very risky environments, and isolated environments," said Jamie Barrett, another psychologist at Wyle on the astronaut selection panel.

This means a person who would make a "good neighbor" — someone who's easygoing and has good social skills, Barrett told Live Science. A good candidate is also very resilient, she added. 

Grounds for disqualification

The panel will disqualify astronaut applicants for a variety of psychological reasons. "We're looking for things that are clinically psychologically wrong with them," Barrett said.

In space, "they're away from their families. They're away from their friends. They [can't feel] the sun or the breeze," she said. So existing psychiatric disorders will probably disqualify them. Marital problems can also make disqualification more likely, but disqualified applicants can always reapply, she said.

Barrett couldn't speak freely about whether the selection process involves giving the applicants stress tests or putting them in challenging situations, but she acknowledged that doing these kinds of activities "would probably be a useful thing to do."

Some other countries' space programs use methods of psychological testing that NASA doesn't allow. "Sometimes we look at [our international partners] with envy at some of the things they get to do that we don't get to do," Slack said, but did not give any examples.

NASA's manned space missions are changing, however, so the qualities used to select astronauts may also change, the psychologists said. Right now, astronauts fly short, six-month missions on the International Space Station, but future missions will likely be much longer, and could include visiting the moon, near-Earth asteroids and, ultimately, Mars. 

The agency is currently developing an updated list of psychological competencies for astronauts, the panelists said.