Aleksei Leonov, Soviet cosmonaut who performed the first space walk. After early schooling in Kaliningrad, Leonov joined the Soviet air force in 1953. He completed his flight training in 1957 and served as a fighter pilot until 1959, when he was selected for cosmonaut training. On March 18, 1965,
Astronaut candidates must undergo a rigorous screening process as well as meet physical and skills requirements to be able to perform effectively in high-stress situations.
By the end of the second decade of the 21st century, over 500 people, coming from 40 different countries and more than 10 percent of whom were women, had flown in space. As of that same time, only the United States, Russia, and China had the capability of carrying out human spaceflights. With the retirement of the space shuttle in 2011, the United States lost its independent human spaceflight capability. Such capability would not be regained until new private commercial spacecraft were ready for use, a development that was anticipated in 2019.
Risks and benefits
Human spaceflight is both risky and expensive. From the crash landing of the first crewed Soyuz spacecraft in 1967 to the breakup of the shuttle orbiter