Artist to prepare air-free environment? (5)
I believe the answer is:
degas
I believe this is a double definition.
'artist' is the first definition.
(I've seen this before)
'prepare air-free environment?' is the second definition.
(to de-gas is to remove gas from an area)
'to' acts as a link.
(Other definitions for degas that I've seen before include "Edgar -, Fr. artist" , "Edgar -, c. Nineteen-twenty Fr. painter" , "Edgar --, French painter and sculptor" , "He painted dancers" , "Edgar -, French impressionist" .)