Kimiya Yui began his professional career within the Japan Air Self-Defense Force in 1992, eventually transitioning to the space sector as a test pilot and astronaut candidate. His progression from military aviation to orbital flight represents a shift in national recruitment priorities for the Japan Aerospace Exploration Agency, leading him to assignments that include long-duration missions and command roles.
Military Service and Selection
Born in 1970 in Kawakami, Yui attended the National Defense Academy of Japan. Following his 1992 graduation, he joined the Japan Air Self-Defense Force. He qualified as an F-15 Eagle pilot and served as a test pilot. By December 2008, he held the rank of Lieutenant Colonel while working in the Air Staff Office's Defense Planning Division. In 2009, JAXA selected him for astronaut training, necessitating his retirement from military service due to national policies separating scientific and defense operations.
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Before orbital flight, Yui participated in undersea training missions. He earned certification as an astronaut in July 2011. During June 2012, he took part in the NEEMO 16 mission aboard the Aquarius underwater laboratory. Along with his crew, he achieved aquanaut status after spending more than 24 hours submerged, completing the mission upon returning to the surface on June 22.
Orbital Expeditions
Yui served as a backup flight engineer for Expedition 42/43. He transitioned to the prime crew for Expedition 44/45, launching from the Baikonur Cosmodrome on July 22, 2015, aboard Soyuz TMA-17M alongside Oleg Kononenko and Kjell Lindgren. During his tenure, he provided robotic support for the JAXA HTV-5 arrival and assisted with spacewalks conducted by Lindgren and Kelly in late 2015. He returned to Earth on December 11, 2015, after 142 days in space. Later, on August 1, 2025, he launched on SpaceX Crew-11 for Expedition 73/74.
Professional Leadership
In addition to his flight duties, Yui assumed administrative responsibilities within the agency. In November 2016, he was appointed Chief of the JAXA Astronaut Corps. His activities are also documented in the 2016 IMAX film A Beautiful Planet.
Fast facts
- Born: 1970, Kawakami, Japan
- Education: National Defense Academy of Japan
- Military Rank: Lieutenant Colonel
- Selected as Astronaut Candidate: 2009
- NEEMO 16 Mission: June 2012
- Expedition 44/45 Launch: 22 July 2015
- Appointed Chief of Astronaut Corps: November 2016
- Expedition 73/74 Launch: 1 August 2025
Questions readers ask
What is Kimiya Yui's military background?
He served as an F-15 Eagle pilot and test pilot, retiring as a Lieutenant Colonel in the Japan Air Self-Defense Force.
How long was Yui in space during his 2015 mission?
He spent 142 days in space, returning to Earth on December 11, 2015.
Achievements
- Educated at National Defense Academy of Japan
- Worked as astronaut and Air Self-defense Official
