NASA astronaut Christina Hammock Koch, a member of the International Space Station (ISS) expedition 59/60, attends her final exam at the Gagarin Cosmonauts' Training Centre in Star City outside Moscow on February 20, 2019. - NASA astronauts Christina Hammock Koch and Nick Hague and Russian cosmonaut Alexey Ovchinin are preparing for the launch onboard the Soyuz MS-12 spacecraft from the Russian-leased Kazakh Baikonur cosmodrome on March 14, 2019. (Photo by STR / POOL / AFP)