Leonid Ivanovitch Sedov was a leading physicist of the Soviet Union

Soviet Union

The Soviet Union , officially the Union of Soviet Socialist Republics , was a constitutionally socialist state that existed in Eurasia between 1922 and 1991....

.

During WW2 he devised the so-called Sedov Similarity Solution for a blast wave

Blast wave

A blast wave in fluid dynamics is the pressure and flow resulting from the deposition of a large amount of energy in a small very localised volume. The flow field can be approximated as a lead shock wave, followed by a 'self-similar' subsonic flow field. In simpler terms, a blast wave is an area of...

. He was also the first chairman of the USSR Space Exploration program

Soviet space program

The Soviet space program is the rocketry and space exploration programs conducted by the former Union of Soviet Socialist Republics from the 1930s until its dissolution in 1991...

 and broke first news of its existence in 1955. He was president of the International Astronautical Federation

International Astronautical Federation

International Astronautical Federation , the world's foremost space advocacy organisation, is based in Paris. It was founded in 1951 as a non-governmental organization. It has 206 members from 58 countries across the world. They are drawn from space agencies, industry, professional associations,...

 (IAF) from 1959 to 1961. Until recently, it had been thought that Sedov was the principle Soviet engineer behind the Sputnik project.