He was selected as a cosmonaut on 1 December 1978 and flew as Flight Engineer on Soyuz T-10 and Soyuz T-15, spending a total of 361 days, 22 hours, 49 minutes in space.

His first flight, Soyuz T-10, took off on 8 February 1984, to join Salyut 7.

The crew spent ten months (nearly 237 days) performing numerous medical and space manufacturing experiments.

Solovyov then became the Mir flight director (Russian Mission Control) for several years.

He retired on 18 February 1994 but came back to head the Russian segment of the International Space Station (ISS).