Andriyan Grigoryevich Nikolayev was a Soviet cosmonaut. He was an ethnic Chuvash.
Nikolayev flew on two space flights: Vostok 3 (effectively becoming the third Soviet cosmonaut) and Soyuz 9. His call sign in these flights was Falcon (Russian: Со́кол). On both, he set new endurance records for the longest time a human being had remained in orbit. He also served as backup for the Vostok 2 and Soyuz 8 missions.