It strains fellow traveller visiting satellite perhaps (8)
I believe the answer is:
colander
'it strains' is the definition.
(a colander might be used to strain a liquid)
'fellow traveller visiting satellite perhaps' is the wordplay.
'fellow' becomes 'co' (eg a co-worker is a fellow worker).
'traveller visiting satellite perhaps' becomes 'lander' (as in a moon lander - the moon is a satellite).
'co'+'lander'='COLANDER'
(Other definitions for colander that I've seen before include "Vessel for draining" , "Utensil for draining vegetables" , "Food strainer" , "Boiled 20 Down may be strained through this" , "Perforated bowl" .)