20th anniv. of space research (6)

First space flight by Yuri Gagarin (1934-1968), air force officer, and cosmonaut. First space walk by Alexei Leonov (born 1934), Cosmonaut. Docking of the spaceship Soyuz to the space station Salyut. Research into the Earth's atmosphere: Satellite Proton 4. Intercosmos program: Satellite Intercosmos 10, docking of Apollo 18 and Soyuz 19. Exploration of the planets of the solar system: space probes Luna, Venus and Mars.