Valentin Vasylovych Bondarenko (, ; 16 February 1937 – 23 March 1961) was a Soviet fighter pilot selected in 1960 for training as a cosmonaut. He died as the result of burns sustained in a fire during a 15-day low-pressure endurance experiment in Moscow. The Soviet government concealed the death, along with Bondarenko's membership in the cosmonaut corps, until 1980. A crater on the Moon's far side is named after him. Education and military training Bondarenko was born in Kharkiv, Ukrainian SSR, Soviet Union. His father was sent to the Eastern Front in the first days of World War II. The youngster and his mother went through several years of hardship during the war. His father volunteering to fight in the Soviet Army instilled the idea of military training into Bondarenko at a young age, leading to his later interest in the Air Force. From an early age, Bondarenko was fascinated by aviation heroes and dreamed of becoming a military aviator himself. While still at Kharkiv's Higher Air Force School, he was a member of the local aviation club. After Bondarenko's graduation in 1954 he was admitted to the Voroshilovgrad Aviation Military Academy and a year later he was transferred to an Air Force College in Grozny, Armavir Military Pilot Aviation School, from which he graduated in 1957. In 1956 he married Galina Semenovna Rykova, a medical worker. Their first child was born later that year. During 1956, Bondarenko was sent to Armavir Higher Air Force Pilots School, graduating in 1957—the same year Sputnik 1 was launched. Bondarenko was commissioned a Second Lieutenant, and served in the Soviet Air Force's PribVO (the former Baltic Military District). He was promoted to Senior Lieutenant in December 1959. Selection for cosmonaut training On 28 April 1960, Bondarenko was chosen to be among the first group of 20 cosmonauts. Bondarenko, "(also known as 'Valentin Junior' and 'Tinkerbell') was the youngest member of the cosmonaut team." He began training on 31 May for a planned launch on the crewed Vostok spacecraft. According to his fellow cosmonauts, Bondarenko was a mild-mannered person with a pleasant disposition. He had a good singing voice and played table tennis well. Death 23 March 1961 was the tenth day of a 15-day endurance experiment in a low pressure altitude chamber at the Institute of Biomedical Problems in Moscow. The chamber's atmosphere was at least 50% oxygen. Bondarenko, having completed work