Mstislav Keldysh was trained in physics and mathematics at Moscow University (Ph.D., 1938), and he became the chief theoretician of Soviet cosmonautics in the 1960s. He had previously served many years in a variety of positions at the Central Institute of Aerohydrodynamics, Moscow University, and the Steklov Mathematical Institute. In 1960-1961 he was Vice President of the Soviet Academy of Sciences, and thereafter as President of the Soviet Academy of Sciences until 1975.