Space research with satellites. "Proton-4" - heavy research satellite to study cosmic rays and interaction with matter particles of ultrahigh energies (launched 16.11.1968). The third Soviet artificial Earth satellite (launched 15.05.1958) - the world's first automatic scientific station in space - on the background of meteorological map of the Earth. Text: "Exploring near-earth space"
On the stamp - the first Soviet artificial Earth satellite (launched 04.10.1957) and the ribbon with the text "XX years of the space age". The pictures on the background of cosmic scenery.