The nation's first astronaut returned home Monday from Russia after returning to Earth April 19th from a 12-day mission in space.

Yi Soyeon arrived at Incheon International Airport shortly after nine a.m. with fellow trainee Ko San.

Yi told a news conference she hasn't heard any details about why her spacecraft veered so far off course during its return to Earth. But she said Russian officials were looking into the matter.

She said that of the 18 experiments she conducted at the International Space Station, the most impressive was a water experiment for children. She said it made her realize the development of space science and technology doesn't come overnight.

On Tuesday, after a formal news conference at the government complex, she'll meet with President Lee Myung-bak and talk about her space trip.

After she's fully recovered from her mission, Yi will take part in national space development projects.