Thomas Gautier Pesquet is a French aerospace engineer, pilot, and European Space Agency astronaut. Pesquet was selected by ESA as a candidate in May 2009, and he successfully completed his basic training in November 2010. From November 2016 to June 2017, Pesquet was part of Expeditions 50 and 51 on the International Space Station as a flight engineer.

Claude Nicollier is the first astronaut from Switzerland. He has flown on four Space Shuttle missions. His first spaceflight (STS-46) was in 1992, and his final spaceflight (STS-103) was in 1999. He took part in two servicing missions to the Hubble Space Telescope (called STS-61 and STS-103). During his final spaceflight he participated in a spacewalk, becoming the first European Space Agency astronaut to do so during a Space Shuttle mission. In 2000 he was assigned to the Astronaut Office Extravehicular Activity Branch, while maintaining a position as Lead ESA Astronaut in Houston. Nicollier retired from ESA in April 2007.

Major Timothy Nigel Peake CMG is a British Army Air Corps officer, former European Space Agency astronaut and International Space Station (ISS) crew member. He is the first British ESA astronaut, the second astronaut to bear a flag of the United Kingdom patch, the sixth person born in the United Kingdom to go on board the International Space Station and the seventh UK-born person in space. He began the ESA's intensive astronaut basic training course in September 2009 and graduated on 22 November 2010

Buzz Aldrin; born Edwin Eugene Aldrin Jr.; is an American engineer, former astronaut, and fighter pilot. As Lunar Module Pilot on the Apollo 11 mission, he and mission commander Neil Armstrong were the first two humans to land on the Moon.

Chris Austin Hadfield is a Canadian retired astronaut, engineer, and former Royal Canadian Air Force fighter pilot. The first Canadian to walk in space, Hadfield has flown two space shuttle missions and served as commander of the International Space Station.

David Saint-Jacques is a Canadian astronaut with the Canadian Space Agency (CSA). He was also an engineer, an astrophysicist, and a physician prior to joining the CSA. He was selected to join the CSA in the 2009 CSA selection along with Jeremy Hansen.

Anne Charlotte McClain is a lieutenant colonel in the U.S. Army currently assigned to NASA Astronaut Group 21.

Andrew Richard "Drew" Morgan is a NASA astronaut from the class of 2013.

Tyler Nicklaus Hague is an American Flight Test Engineer and a NASA astronaut of the class of 2013. Selected to be a flight engineer of Expedition 57 / 58 to the International Space Station, he launched on board Soyuz MS-10, which aborted shortly after launch on October 11, 2018.

Terry W. Virts Jr. is a former NASA astronaut, and Colonel in the United States Air Force.

Alexander Gerst is a German European Space Agency astronaut and geophysicist, who was selected in 2009 to take part in space training. He was part of the International Space Station Expedition 40 and 41 from May to November 2014. Gerst returned to space on June 6, 2018, as part of Expedition 56/57 as the ISS Commander.

Richard Alan "Rick" Mastracchio is an American engineer and former NASA astronaut. He has flown on three NASA Space Shuttle missions as a mission specialist in addition to serving as a Flight Engineer on the Soyuz TMA-11M (Expedition 38/Expedition 39) long duration mission aboard the International Space Station. He is currently the Senior Director of Operations for Commercial Resupply Services at Orbital ATK.