Valeri Vladimirovich Polyakov (, ; born Valeri Ivanovich Korshunov []; 27 April 1942 – 7 September 2022) was a Soviet and Russian cosmonaut. He is the record holder for the longest single stay in space, staying aboard the Mir space station for more than 14 months (437 days, 18 hours) during one trip. His combined space experience was more than 22 months.

Selected as a cosmonaut in 1972, Polyakov made his first flight into space aboard Soyuz TM-6 in 1988. He returned to Earth 240 days later aboard TM-7. Polyakov completed his second flight into space in 1994–1995, spending 437 days in space between launching on Soyuz TM-18 and landing with TM-20, setting the record for the longest time continuously spent in space by an individual.

Polyakov's second spaceflight, the longest human spaceflight in history, began on 8 January 1994 with the launch of the Soyuz TM-18 mission. He spent approximately 437 days aboard Mir, conducting experiments and performing scientific research. During this flight, he completed just over 7,000 orbits of the Earth. On 9 January 1995, after 366 days in space, Polyakov formally broke the spaceflight duration record previously set by Vladimir Titov and Musa Manarov six years earlier. He returned to Earth aboard Soyuz TM-20 on 22 March 1995.

Polyakov volunteered for his 437-day flight to learn how the human body would respond to the micro-gravity environment on long-duration missions to Mars.

Polyakov underwent medical assessments before, during, and after the flight. He also underwent two follow-up examinations six months after returning to Earth. When researchers compared the results of these medical exams, it was revealed that although there were no impairments of cognitive functions, Polyakov experienced a clear decline in mood as well as a feeling of increased workload during the first few weeks of spaceflight and return to Earth. Polyakov's mood stabilized to pre-flight levels between the second and fourteenth month of his mission. It was also revealed that Polyakov did not suffer from any prolonged performance impairments after returning to Earth. In light of these findings, researchers concluded that a stable mood and overall function could be maintained during extended duration spaceflights, such as crewed missions to Mars. to 27 April 1989, 02:57:58 UTC – 240 days, 22 hours, 34 minutes and 47 seconds

  • Soyuz TM-18 / Soyuz TM-20 – 8 January 1994, 10:05:34 UTC – 437 days, 17 hours, 58 minutes and 31 seconds

Later life

Polyakov retired from his position as a cosmonaut in June 1995, with a total of just over 678 days in space. He participated in experiment SFINCSS-99 (Simulation of Flight of International Crew on Space Station) in 1999. Polyakov was the Deputy Director of the Ministry of Public Health in Moscow, where he oversaw the medical aspects of long-duration space missions. Polyakov was married and had one child.

Legacy

Polyakov won several awards for his spaceflight and academic achievements, including the Hero of the Soviet Union, Hero of the Russian Federation, Order of Lenin, Order of the Legion of Honour, and the Order of Parasat. He was a member of organizations related to astronautics, including the Russian Chief Medical Commission on cosmonauts' certification.

Honours and awards

  • Hero of the Russian Federation
  • Hero of the Soviet Union
  • Officer of the Legion of Honour (France)
  • Order of Parasat (Kazakhstan)