Yi So-yeon

Yi So-yeon was born in 1978 and trained as a scientist rather than a pilot, an increasingly common route to orbit for spaceflight participants. She earned bachelor's and master's degrees in mechanical engineering at the Korea Advanced Institute of Science and Technology (KAIST) and was completing a doctorate in biological science, working in nano-bio research, when the Korean Astronaut Program opened its national search. From roughly 36,000 applicants she emerged as one of two finalists sent to Russia for cosmonaut training. Originally the backup, she was elevated to the prime crew in March 2008 after her male counterpart, Ko San, was removed for repeatedly violating training-center security rules — a late change that put a 29-year-old biotechnologist in line to become the first Korean in space.

On 8 April 2008, Yi launched aboard Soyuz TMA-12 from the Baikonur Cosmodrome with Russian cosmonauts Sergei Volkov and Oleg Kononenko, docking with the International Space Station as a spaceflight participant. Over about eleven days — nine of them aboard the station — she carried out eighteen experiments arranged by the Korea Aerospace Research Institute (KARI), spanning plant growth in microgravity, the behavior and genetics of fruit flies she had carried up in a special container, and studies of how spaceflight altered her heart, eye pressure, and facial shape. Famously, she brought a specially engineered 'space kimchi': Korean scientists had spent years and considerable expense adapting the fermented dish so it would keep in orbit without producing odors that might trouble her crewmates. Her return on 19 April was harrowing — the Soyuz TMA-11 capsule she shared with Peggy Whitson and Yuri Malenchenko made a steep ballistic re-entry that subjected the crew to unusually high g-forces and landed well off target, leaving Yi with a back injury.

Yi held a singular place in her country's history as South Korea's first and, to date, only astronaut, and she was decorated with the Order of Civil Merit. She became a prominent advocate for Korean STEM education and for women in science, drawing on her flight to reflect on how small and vulnerable humanity appears against the vastness of Earth seen from orbit. In the years after her mission she stepped back from the space program and moved to the United States, pursuing an MBA and further studies, and she is now retired from active astronaut duties. Her flight nonetheless remains a defining chapter for the Korean Astronaut Program and an enduring symbol of a scientist reaching orbit on the strength of research rather than test-pilot credentials.