Handset oddly lost on new space adventure (8)
I believe the answer is:
escapade
'adventure' is the definition.
(I know that adventure can be written as escapade)
'handset oddly lost on new space' is the wordplay.
'oddly lost' means one should take alternating letters (letters in odd-numbered positions removed).
'on' means one lot of letters go next to another.
'new' is an anagram indicator.
The alternate letters of 'handset' are 'ade'.
'space' anagrammed gives 'escap'.
'ade' after 'escap' is 'ESCAPADE'.
(Other definitions for escapade that I've seen before include "Caper" , "Exciting, perhaps mischievous, adventure" , "quite a lark" , "Mischievous romp" , "Adventure, lark" .)