Nikolai Semenovich Kardashev (Никола́й Семёнович Кардашёв) (born April 25, 1932 in Moscow) is a Russian astrophysicist, Doctor of Physical and Mathematical Sciences, and is the deputy director of the Astro Space Center (Russia) of PN Lebedev Physical Institute of the Russian Academy of Sciences in Moscow.
Kardashev graduated from Moscow State University in 1955, following up at Sternberg Astronomical Institute. He studied under Shklovskii and finished his PhD in 1962.
In 1963 Kardashev examined quasar CTA-102, the first Soviet effort in the search for extraterrestrial intelligence (SETI). In this work he came up with the idea that some galactic civilizations would be perhaps millions or billions of years ahead of us, and created the Kardashev classification scheme to rank such civilizations. Kardashev defined three levels of civilizations, based on energy consumption: Type I with "technological level close to the level presently attained on earth, with energy consumption at ≈4×1019 erg/sec (4 × 1012 watts)". Type II, "a civilization capable of harnessing the energy radiated by its own star", and Type III, "a civilization in possession of energy on the scale of its own galaxy". Serious Russian efforts in SETI predate similar programs in the US by some years. Other notable experts in the USSR were Vsevolod Troitskii and Iosif Samuilovich Shklovskii (Kardashev's former professor).
Kardashev became a corresponding (associate) member of the USSR Academy of Sciences, Division of General Physics and Astronomy on December 12, 1976. He became a full member of the Russian Academy of Sciences on March 21, 1994 and was awarded the Demidov Prize in 2014.
- Kardashev, Nikolai (1985). "On the Inevitability and the Possible Structures of Supercivilizations" in "The search for extraterrestrial life: Recent developments; Proceedings of the Symposium, Boston, MA,June 18–21, 1984". pp. 497–504. Bibcode:1985IAUS..112..497K.