Spacecraft's whole during landing (7)
I believe the answer is:
pioneer
'spacecraft's' is the definition.
(I've seen this before)
'whole during landing' is the wordplay.
'whole' becomes 'one' ('one' can be a synonym of 'whole').
'during' means one lot of letters goes inside another.
'landing' becomes 'pier' (pier is a kind of landing).
'one' going into 'pier' is 'PIONEER'.
(Other definitions for pioneer that I've seen before include "Colonist" , "Open up an area" , "To take first step" , "Lead the way" , "Innovate" .)