So you want to be an astronaut? Here's what it takes

Rachel Nuwer | Special for USA TODAY

The prospect of gazing down at Earth's blue marble, conducting cutting-edge extraterrestrial research and perhaps even exploring new worlds holds irresistible allure for thousands of hopefuls who regularly apply to be NASA astronauts. Yet only a handful of candidates ever land one of these coveted positions.

In order to attract NASA's eye, aspiring astronauts must not only excel in required skills and pass rigorous physical exams, they must also find unique ways to distinguish themselves from the stiff competition.

"If a student comes to me and says, 'I want to be an astronaut,' I tell them, 'Great: Excel in your coursework, go get a piloting license and learn to play the guitar,'" said John Armstrong, a professor of physics at Weber State University.

For any given applicant, the odds of being selected as an astronaut are minute, regardless of how qualified he or she may be. Between 4,000 and 8,000 people enter each application round, and only eight to 35 are selected. Currently, NASA takes new trainees every four to five years, and this year, NASA waded through more than 6,000 applications, eventually whittling that pool to just eight people.

So when he advises students who dream of spacewalking, Armstrong also recommends they have a realistic backup plan.

In busier years, NASA launched up to nine shuttle missions, each manned by five astronauts, on average. These days, only one American gets to ride with the Russians to the International Space Station, and that opportunity comes around just three times per year.

NASA's requirements for becoming an astronaut have changed over the years. Originally, the administration favored candidates with a military flight background, with at least 1,000 hours spent in command of a jet aircraft.

In 1978, however, NASA shifted its focus to a more diverse group of astronauts: scientists and engineers with at least three years of experience in their respective fields, referred to as mission specialists. During the years of shuttle missions, everyone had a specialty; some would focus on robotics, others on spacewalks or maintenance.

Now, to work on the space station, astronauts must be able to perform all tasks, which encourages applicants to acquire a diversity of experiences. "I think our crazy, varied backgrounds contribute to our ability to adapt and learn anything quickly, and then assimilate that knowledge into our skill set," said Jeanette Epps, an astronaut who studied aerospace engineering, worked at Ford Motor Company and took a job with the CIA before joining NASA.

NASA has always required its astronauts to hold a degree in engineering, math or science. Many astronauts attained doctorate degrees, and nearly all earned master's degrees.

Historically, about half of NASA's astronauts came from an engineering background, but specialties include medicine, chemistry, biology and veterinary science. "If we have 50 astronauts, we have about 50 different educational backgrounds, but they're all technical," said astronaut Mike Foreman.

After ensuring that applicants are U.S. citizens and that they satisfy basic education and experience requirements, the selection committee enters a gray realm. Translated, NASA looks for any experience "related to the kinds of things astronauts do," said Duane Ross, the manager for astronaut candidate selection and training. "We're not really looking for one thing, just a good mix of things."

To the committee, candidates who take on challenges outside of the workplace demonstrate curiosity and energy. Many astronauts who don't have a military background do hold a private piloting license. Some are avid mountain climbers, scuba divers or skiers. Others are musicians, dancers or play competitive sports.

"Many of them just tend to excel at everything they do," said Valerie Neal, who curates space-era artifacts at the Smithsonian National Air and Space Museum. "They tend to undertake whatever they do with the full force of their abilities to reach a level of excellence."

Choosing to expose themselves to different, extreme environments—the "earthling analogues for a mission to Mars"—counts as another way to stand out from the crowd, Neal said. While working for the CIA, Epps volunteered to be deployed to Iraq for four months, though others chose Antarctica or the deep sea.

For the 100 or so candidates who make it to the final interview, personality counts. In space, astronauts live in cramped quarters with a handful of people for six months. Getting along with others is a necessity.

"It comes down to how much of a positive impression you make on the interview panel," said Tom Jones, a former NASA astronaut who flew on four shuttle missions. "They size you up in an hour and decide if you're a person they and others would like to work with."

Finally, candidates must pass a rigorous set of physical and psychological exams. "You have to sort of be lucky just to pass the physical," said former astronaut Mary Cleave, veteran of two shuttle missions. The exam includes meeting specific standards for height, blood pressure and eyesight.

"Basically, we're looking for nice people who can do the job, pass the medical requirements and can be part of a team for a long duration in an isolated environment," Ross said. "The good news is we've got a lot more great people than we could ever take."

Applicants in this latter group are encouraged to reapply. Foreman applied seven times before getting an invitation to interview, only to be rejected. On his eighth try, he again received an interview invitation.

"One of the astronauts on the interview panel said, 'Mike, we didn't pick you two years ago, why should we pick you now?'" Foreman recalls. "I laughed and said, 'I don't know, I hope you can find a reason to select me this time.'"

Nine months later, the call came: He had been selected.

AN ASTRONAUT'S CARRY-ON

When many of your personal items have to fit in a pouch the size of a soda can, packing for space can be tricky.

Spending time in space is "like living in a phone booth with six other people," said astronaut Mike Foreman.

Given the constraints, NASA imposes strict limitations on what leaves the planet—astronauts can bring 20 small personal items packed into a zipper pouch about the size of a soda can. They're also allowed to bring clothing items that fit into an assigned drawer, as well as approved items they plan to use in educational video dispatches.

Still, many astronauts do bring memorabilia: Foreman, an avid Houston Astros fan, took jerseys from his favorite players, Roy Oswalt and Lance Berkman.

Tom Jones took a Baltimore Orioles cap as well as a T-shirt from his high school. He also brought along a hardback copy of Arthur C. Clarke's 2001: A Space Odyssey, an appropriate choice for his shuttle flight, which launched in February 2001.

Jeanette Epps hasn't been to space yet, but plans to take a University of Maryland shirt, a teddy bear for her nephew and an Alvin and the Chipmunks "Jeanette" chipmunk doll.

Former astronaut Mary Cleave was caught sneaking an "unmanifested" item onto her mission. "They actually ask you to empty your pockets, and I had this little, mounted four-leaf clover in my flight pocket," she said.

She had found the lucky leaf at summer camp years before and was in the habit of carrying it with her whenever she flew. "The guys just sort of laughed at me," she recalls. The clover made the flight.

This article is excerpted from USA TODAY's special publication NASA's Future in Space, available on newsstands or at nasa.usatoday.com.