Yui is the first Japanese astronaut with military background, and was forced to retire due to the historical policy by Japanese government which separates the scientific field from military works. The NEEMO 16 crew successfully "splashed down" at 11:05 am on June 11. On the morning of June 12, Yui and his crewmates officially became aquanauts, having spent over 24 hours underwater. The crew safely returned to the surface on June 22. In November 2016, Yui became Chief of the
JAXA Astronaut Corps.
Expedition 44/45 In 2013, Yui was assigned as backup flight engineer for
Italian astronaut
Samantha Cristoforetti for ISS
Expedition 42/
43. Cristoforetti launched onboard
Soyuz TMA-15M alongside fellow Expedition 42/43 crewmembers
Anton Shkaplerov and
Terry Virts 23 November 2014, following which Yui began training as prime crew Flight Engineer for ISS
Expedition 44/
45 alongside
Roscosmos cosmonaut
Oleg Kononenko and
NASA astronaut
Kjell Lindgren. Yui launched onboard
Soyuz TMA-17M alongside Kononenko and Lindgren on 22 July 2015 from the
Baikonur Cosmodrome in
Kazakhstan, a solar panel on the Soyuz failed to deploy once the spacecraft got to orbit although this was not mission-critical, and the crew successfully docked with the ISS six hours later, officially becoming members of the Expedition 44 crew alongside Russian cosmonauts
Gennady Padalka and
Mikhail Kornienko as well as NASA astronaut
Scott Kelly. During Expedition 44 Yui robotically supported the arrival of
JAXAs
HTV-5 uncrewed resupply spacecraft in August 2015 and was part of a rare "direct handover" period on board the ISS where nine crew members were present on board the station following the arrival of
Soyuz TMA-18M and before the departure of
Soyuz TMA-16M, this handover was carried out in order to allow Kornienko and Kelly to remain on board the ISS for a
full year. Yui remained on board the ISS alongside Lindgren, Kononenko, Korneninko and Kelly following the departure of
Soyuz TMA-16M, after which the five transferred over to Expedition 45, they were joined by Russian cosmonaut
Sergey Volkov who brought the crew up to six members. During Expedition 45 Yui supported two spacewalks, made by Lindgren and Kelly on 28 October and 6 November 2015, and supported the arrival of
Orbital ATK's
OA-4. On 11 December 2015, Yui, alongside Kononenko and Lindgren undocked from the ISS, officially ending Expedition 45 and starting
Expedition 46, and landed on the
Kazakh Steppe on the same day following 142 days in space.
Expedition 73/74 On August 1, 2025, he launched aboard
SpaceX Crew-11 for
Expedition 73/
74. == See also ==