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.