[1] Soyuz 40 was the 16th expedition to Salyut 6 and carried the ninth international crew.

It also ended the first phase of the Intercosmos program by carrying Romanian cosmonaut Dumitru Prunariu and Soviet cosmonaut Leonid Popov to the station.

During the crew's stay, Prunariu studied the Earth's magnetic field.

Earth observations had to be delayed until the last day of the flight, when Salyut 6 passed over Romania in daylight.

During this time the crew also tested the station's orientation system.