Soyuz 39 was a 1981 Soviet manned space flight to the Salyut 6 Space Station. It was the fifteenth expedition, and carried the 8th international crew to the orbiting facility. The crew visited Vladimir Kovalyonok and Viktor Savinykh, who had reached Salyut-6 ten days prior.

The flight carried Vladimir Dzhanibekov and Jugderdemidiin into space. With this mission, Gürragchaa became the first Mongolian, and second Asian cosmonaut.

The Mongolian contribution for this mission had begun in 1967, when the president of the Mongolian Academy of Sciences Bazaryn attended a conference of scientists from socialist countries in Moscow, where the Intercosmos project was announced. Dzhanibekov and Gürragchaa performed about thirty experiments during the course of the mission.

On 27 March, Vladimir Kovalyonok and Viktor Savinykh of the resident crew used the Gologramma ("hologram") apparatus to image a viewing port damaged by micrometeoroids. They repeated this experiment the next day, when they also collected samples of the station's air and microflora and removed the cosmic ray detectors for return to Earth. 28–29 March were largely devoted to studies of Mongolia from space. The visiting crew also checked out their spacecraft on 29 March

The Soviet news service TASS noted that by 29 March, Salyut 6 had conducted 20,140 revolutions of Earth.

The Mongolian contribution for this mission had begun in 1967, when the president of the Mongolian Academy of Sciences Bazaryn Shirendev attended a conference of scientists from socialist countries in Moscow, where the Intercosmos project was announced.

Soyuz 39 marked the eighth Intercosmos mission (with Zhugderdemidiyn Gurragcha, the first cosmonaut from Mongolia). Following a one-day solo flight Soyuz 39 docked with the Salyut 6 space station on March 23, 1981. During the next days the crew performed common scientific work with the fifth resident crew.

The cosmonauts installed cosmic ray detectors in the work and transfer compartments. They also performed the Illyuminator ("viewing port") experiment, which studied the degradation of the station's viewports. Vladimir Kovalyonok and Viktor Savinykh also used the Gologramma ("hologram") apparatus to image a viewing port damaged by micrometeoroids. They also collected samples of the station's air and microflora and removed the cosmic ray detectors for return to Earth. Experiments of Earth science were also performed, especially studies of Mongolia from space.

The results of the Biosphere-Mon experiment would also prove of great benefit for Mongolia's national economy. Its purpose was to study various objects on the Earth's surface by means of special instruments installed on board Salyut 6. The crew carried out 14 observation assignments over the territory of Mongolia in the interests of geology, agriculture, glaciology, landscape science and meteorology.

The Atmosphere, Horizon and Terminator experiments provided information about the transfer functions and other optical characteristics of the Earth's atmosphere. They were carried out by means of the Spectrum-15 instrument developed by Bulgarian specialists. The same instrument was used in the Illuminator and Solongo experiments, the former dealing with the study and qualitative assessment of changes in the spectral transparency of the Salyut station's viewports during its long orbital flight, and the latter aimed at obtaining spectral data on various terrestrial formations.