Pioneering Russian paper set up in advance (7)
I believe the answer is:
gagarin
'pioneering russian' is the definition.
(Yuri Gargarin, first man in space)
'paper set up in advance' is the wordplay.
'paper set up' becomes 'gar' (I can't explain this - if you can you should give a lot more credence to this answer).
'in' means one lot of letters goes inside another.
'advance' becomes 'gain' (synonyms).
'gar' going into 'gain' is 'GAGARIN'.
(Other definitions for gagarin that I've seen before include "Yuri ....... first man in space" , "circumnavigator" , "Yuri ......, first Russian into space" , "old spaceman" , "Yuri . . . . . . . made the first manned space flight" .)