Gdzie zaczyna się kosmos?

This apparently abstract question has an essential practical dimension. The more and more intensive space exploration (as for instance International Space Station Alpha, China’s space programme, or recently declared acceleration of the USA developments in this area) causes increasing aspirations to enforce clear legal regulations in this field. Space law, however, in spite of over fifty years of legislation works, still shows numerous lacks and deficiencies. Even basic definitions concerning for instance a space object or space have not been defined. Therefore the problem of space clear definition becomes fundamental, first of all because of a lower frontier of space, i.e. the border between air and space. The attempts to draw legal international distinction between these two zones have been effortlessly undertaken by scientists since the end of the 50s in the 2Cfh century. Since the 60s intensive, also not very effective works have been carried out to delimit space within the United Nations. The article also outlines developments in space delimitation and its current research and perspectives.