Cosmonauts:
    Alexi A. Leonov [2], Commander
    Valeri N. Kubasov [2], Flight Engineer
Backup:
    Anatoli V. Filipchenko
    Nikolai N. Rukavishnikov
Launch:
    Date: 15 July 1975
    Time: 12:20 UTC
Landing:
    Date: 21 July 1975
    Time: 10:51 UTC
Duration: 5 days, 22 hours, 31 minutes
Call Sign: Union

Soyuz 19 and ASTP met in the culmination of a plan agreed to by treaty in 1972. A universal docking mechanism was designed to enable the two craft to dock. Each astronaut and cosmonaut had at least one opportunity to visit each other's capsules.

This mission not only had a backup crew, but also a backup capsule. This capsule later flew as Soyuz 22. Prime crew for the backup capsule were Vladimir Dzhanibekov and Boris Andreyev. There was even a backup crew for them, consisting of Yuri Romanenko and Aleksandr Ivanchenkov.

(click to enlarge)