Ukrainian cosmonaut (astronaut) who flew on the U.S. space shuttle Columbia and was the first Ukrainian citizen in space.

Upon graduating from the Chernihiv Higher Air Force School in 1971, Kadenyuk became a flight instructor until his enrollment in 1976 at the Air Force Cosmonaut Training Centre. Although he graduated from the Yury Gagarin Cosmonaut Training Centre in Star City in 1978, nearly 20 years passed before Kadenyuk's first spaceflight, which ironically was not aboard the Soviet Soyuz craft for which he trained as a flight engineer but aboard an American space shuttle.

While in the cosmonaut program, Kadenyuk received flight training in numerous types of craft, including the Soyuz, the Soyuz-TM, the Salyut space station, and the Mir orbital complex. He trained as commander for the Buran orbiter and is credited with having improved that craft's landing and lowering trajectories. As a test pilot he mastered 54 types of aircraft, and in 1989 he earned a master's degree in mechanical engineering from the Moscow Aviation Institute. Kadenyuk's training also included studies in biology and botany, with an emphasis on scientific experimentation in microgravity.

In 1996 he joined the Institute of Botany at the National Academy of Sciences of Ukraine as part of a Ukrainian-American space biology collaboration. On Nov. 19, 1997, Kadenyuk flew as a payload specialist aboard the space shuttle Columbia on the STS-87 mission, where he conducted experiments to observe the effect of weightlessness on plant growth and biomass. Kadenyuk was later appointed adviser to the Ukrainian president on aviation and aeronautics and in 2002 was elected to the Ukrainian parliament, where he served as vice-chairperson of the National Security and Defense Committee.