He was a prominent physicist, author of a number of textbooks, and collaborator on the Soviet atomic bomb project who lived mainly in Moscow.
Kompaneyets was a student of Lev Landau in Kharkiv in the 1930s, where he dealt with solid state physics (electrical conductivity in metals and semiconductors).
He also dealt with the physics of detonation, which he wrote about in a book with Yakov Zeldovich, and generally about gases at high temperatures.
In the nuclear weapons program, he worked among others, Zeldovich since the 1940s (at the Institute of Chemical Physics), even at the theoretical examination (from 1948) of the early proposals (1946) of Zeldovich, Isaak Gurevich, Isaac Jakovlevic Pomeranchuk and Yulii Khariton on the hydrogen bomb.
[1] КОМПАНЕЕЦ Александр Соломонович (Entry in the Российская еврейская энциклопедия, Russian, accessed January 9, 2020)