J&C

SEOUL, South Korea — After South Korea began sending soldiers to fight beside American forces in Vietnam, President Park Chung-hee made an unusual plea. He wrote to President Lyndon Johnson to say that his troops were miserable, desperate for kimchi, the fermented cabbage dish that Koreans savor with almost every meal.

Chung Il-kwon, then the prime minister, delivered the letter to Washington. When he traveled overseas, he told Johnson, he longed for kimchi more than for his wife. The president acquiesced, financing the delivery of canned kimchi to the battlefield.

Now kimchi is set to conquer the final frontier: space.

When South Korea’s first astronaut, Ko San, blasts off April 8 aboard a Russian spaceship bound for the International Space Station, the beloved national dish will be on board.

Three top government research institutes spent millions of dollars and several years perfecting a version of kimchi that would not turn dangerous when exposed to cosmic rays or other forms of radiation and would not put off non-Korean astronauts with its pungency.

Their so-called space kimchi won approval this month from Russian authorities.

“This will greatly help my mission,” Mr. Ko, who is training in Russia, said in a statement transmitted through the Korea Aerospace Research Institute. “When you’re working in spacelike conditions and aren’t feeling too well, you miss Korean food.”

Kimchi has been a staple of Koreans’ diets for centuries. These days, South Koreans consume 1.6 million tons a year. Until recently, homemakers would prepare the dish by early winter, then bury the ingredients underground in huge clay pots. Now, many buy their kimchi at the store and keep it in special kimchi refrigerators, which help regulate the fermentation process.

It is hard to overstate kimchi’s importance to South Koreans, not just as a mainstay of their diet, but as a cultural touchstone. As with other peoples attached to their own national foods — Italians with their pasta, for example — South Koreans define themselves somewhat by the dish, which is most commonly made with cabbage and other vegetables and a variety of seasonings, including red chili peppers.

Many South Koreans say their fast-paced lives, which helped build their country’s economy into one of the biggest in the world in a matter of decades, owe much to the invigorating qualities of kimchi. Some take a kind of macho pleasure watching novices’ eyes water when the red chili makes contact with their throats the first time. And when Korean photographers try to organize the people they wish to take pictures of, they yell, “Kimchiiii.”

Mr. Ko’s trip will be an occasion for national celebration. Since 1961, 34 countries, including Vietnam, Mongolia and Afghanistan, have sent more than 470 astronauts into space. Koreans found their absence among the countries that fielded space missions humiliating, given their country’s economic stature. The government finally decided in 2004 to finance sending one scientific researcher into space.

Mr. Ko, a 30-year-old computer science engineer, beat 36,000 contestants in a government competition to earn his spot on board the Russian-made Soyuz rocket. He will travel with two cosmonauts and will stay in the International Space Station for 10 days conducting experiments.

Space cuisine has come a long way since the early days of exploration, when most of the food was squeezed out of tubes before it was discovered that regular food could be consumed in conditions of weightlessness. Now, astronauts can order from a fairly wide variety of foods, from chicken teriyaki to shrimp cocktail, with some modifications. For instance, hamburger rolls produce crumbs that can float off and clog equipment, so other breads are used. But the food at least looks, smells and tastes familiar.

Still, guest astronauts may carry special cuisine. One, Charles Simonyi, who spent part of the fortune he made at Microsoft to travel as a “space tourist” last year, took along a six-course meal prepared by the French chef Alain Ducasse.

The South Koreans created versions of several other foods for Mr. Ko’s mission, including instant noodles, hot pepper paste, fermented soybean soup and sticky rice. But kimchi was the toughest to turn into space food.

“The key was how to make a bacteria-free kimchi while retaining its unique taste, color and texture,” said Lee Ju-woon at the Korean Atomic Energy Research Institute, who began working on the project in 2003 with samples of kimchi provided by his mother.

Ordinary kimchi is teeming with microbes, like lactic acid bacteria, which help fermentation. On Earth they are harmless, but scientists feared they could turn dangerous in space if cosmic rays and other radiation cause them to mutate.

Another problem was that kimchi has a short shelf life, especially when temperatures fluctuate rapidly, as they sometimes do in space.

“Imagine if a bag of kimchi starts fermenting and bubbling out of control and bursts all over the sensitive equipment of the spaceship,” Mr. Lee said.

He said his team found a way to kill the bacteria with radiation while retaining most of the original taste.

Kim Sung-soo, a Korea Food Research Institute scientist who also worked on “space kimchi,” said another challenge was reducing the strong smell, which can cause non-Koreans to blanch. He said researchers were able to reduce the smell by “one-third or by half,” according to tests conducted by local food companies.

Mr. Ko, the Korean astronaut, said he would use the kimchi to foster cultural exchange. He plans to prepare a Korean dinner in the space station on April 12 to celebrate the 47th anniversary of the day the Soviet cosmonaut Yuri Gagarin became the first human in space.

The developers of the “space kimchi,” meanwhile, say their research will continue to benefit South Korea in a practical way even after the country’s national pride is burnished by Mr. Ko’s historic mission.

They say kimchi’s short shelf life has made exporting it expensive because the need for refrigeration and rapid transport. That has added to the cost in importing countries, limiting sales.

“During our research, we found a way to slow down the fermentation of kimchi for a month so that it can be shipped around the world at less cost,” Mr. Lee said. “This will help globalize kimchi.”