Kardashev

Nikolai Semyonovich Kardashev was a Russian astronomer most famous for  writing “Transmission of Information by Extraterrestrial Civilizations” in 1964 that includes the origin of what id known as the Kardashev Scale of civilizations levels 1 to 3.

Borne in Moscow on the 25 April 1932 he had a very illustrious long career up to his death at 87 on the 3 August 2019.

Also wrote in 1985 "On the Inevitability and the Possible Structures of Supercivilizations" that argues that advanced technological civilizations inevitably expand to utilize immense cosmic energy and material resources, necessitating the construction of large-scale, detectable engineering marvels. He proposes that supercivilizations likely develop over billions of years, creating compact, stable, and highly intelligent structures across galaxies

He also proposed Very Long Baseline Interferometry (VLBI),