S75-21892 (20 Feb. 1975) --- Astronaut Thomas P. Stafford (left) and cosmonaut Aleksey A. Leonov participate in Apollo-Soyuz Test Project joint crew training in Building 35 at NASA's Johnson Space Center. Stafford and Leonov are the commanders of their respective prime crews. They are in the Soviet Soyuz Orbital Module mock-up. This picture was taken during a ?walk-through? of the second day?s activities in Earth orbit.