Yuri —, Soviet cosmonaut who made the first manned space flight in 1961 (7)
I believe the answer is:
gagarin
(Other definitions for gagarin that I've seen before include "Yuri --, cosmonaut" , "Yuri ......, first Russian into space" , "circumnavigator" , "Yuri --, space pioneer" , "Yuri . . . . . . . made the first manned space flight" .)