Before Mamoru Mohri was selected as a NASA astronaut candidate by the National Space Development Agency of Japan (NASDA), one rigorous aspect of his preparation was 400 hours of English class. Chris Hadfield, a Canadian astronaut, had to learn Russian.

Eventually, they both had to take the plunge.

Hadfield and Mohri (scheduled to fly on STS 99) swam three lengths of an Olympic-sized pool during their early training. -- In their tennis shoes -- Wearing a 200-pound (91 kilogram) flight suit. -- Just like the Americans.

You see, no matter where you are from, astronaut training is tough. And while the physical standards are high, the mental demands are equally challenging. Regardless of your country of origin.

"The biggest language problem is for the Americans, some of whom have never studied another language," Hadfield said in an interview. He added that learning a fifth language is far easier than learning a second -- especially at 36, the average age for astronaut hires.

Like many people involved in the process, Hadfield stressed that language and cultural differences are becoming increasingly moot in the new era of cooperation in space. A greater hurdle for candidates is grasping the increasingly complex systems, of which all astronauts must have knowledge. From the space shuttle to the fledgling International Space Station, there's a lot to learn.

That's where the pool comes in.

The most demanding part of astronaut training, Hadfield said, is an underwater "spacewalk" that lasts eight to 12 hours -- without food or rest -- in a stiff, thick, pressurized suit. "It's like a semi-rigid balloon," he explained, "like your own personal spaceship."

What prepared the Canadian for such an ordeal, and the equally arduous tasks in space? Working on his family corn farm in southern Ontario.

"If you look at life in space, it's as if you have a collection of implements and you're a long way away from the garage," Hadfield said. "You have to understand how all of the machinery works."

Sounds like an explanation that could have come from an astronaut from Kansas. Or the German hinterland. Or Sweden. Or Japan. Astronauts do come from all these countries -- and others. German Gerhard P.J. Thiele will be a mission specialist aboard STS 99.

Of the 25 astronauts admitted to the most recent NASA astronaut-training class, conducted in 1998, six were from other countries. The program, which takes in new prospects every two years, has ranged in class size from 19 to 35 since 1978, a year in which 8,079 Americans applied. In recent years, that number has dropped to below 3,000.

The first foreign applicants were admitted in 1980, in advance of the initiative to send international teams to a space station. Like their American counterparts, each of the 26 foreign candidates over the years has survived training and become an astronaut.

"All the folks we've taken have made it through the program, and all of them have gone on to fly," said Duane Ross, who oversees candidate training at the Johnson Space Center in Houston. "I always think that's because we have a rigorous selection process. You'd be pretty dumb to wind up taking somebody who couldn't do the job for you."

Each foreign country or space agency sets its own requirements for candidates, based on basic guidelines laid out by NASA, Ross said. The countries and agencies then negotiate how many will be admitted, and it's up to the individual countries to winnow their many applicants down to the handful that NASA agrees on.

Upon arrival in Houston, there's no special treatment for foreigners. "Once they have made it to us and joined up with the class, then they're exactly the same as the NASA astronauts," Ross said. "They join the class and do whatever the class does."

Though only a small number of hopeful space fliers ever make it to Houston, there is no lack of candidates from abroad. In the first year that the program was opened to Canadians, several thousand people applied.

The fortunate few who make it receive much more attention in their home country than American astronauts.

"There are only seven Canadian astronauts, so we get much more focus individually," Hadfield says. "When a Canadian gets launched into space, it's still a very significant event in Canadian society."

In Japan last year, 864 hopefuls signed up. Three were selected.

Mohri, a mission specialist who will operate a data recorder and computer on STS 99, was the first Japanese astronaut to go up. His 1992 flight jump-started Japan's interest in spaceflight.

Many Japanese people now see space activities and astronauts as hopeful signs for society, says Akiko Suzuki, a NASDA public affairs officer working in Houston.

"Space is regarded as a new frontier in Japan," she said.

Suzuki said that after Mohri's first flight, many Japanese children began dreaming of being astronauts.

Like their elder astronaut hopefuls, the youngsters are finding a lot of competition for their dreams. At the Cosmic College, a Japanese space camp for children, officials are turning away pint-sized applicants every year.

Images: NASA