Robert goes wrong fixing one satellite (7)
I believe the answer is:
orbiter
'satellite' is the definition.
(I know that orbiter is a type of satellite)
'robert goes wrong fixing one' is the wordplay.
'goes wrong' indicates an anagram.
'fixing' indicates putting letters inside (inserted letters are fixed inside others).
'one' becomes 'i' (Roman numeral).
'robert' anagrammed gives 'orbter'.
'orbter' enclosing 'i' is 'ORBITER'.
(Other definitions for orbiter that I've seen before include "Craft going round planet" , "Circling spacecraft" , "Space vehicle" , "Non-landing spacecraft" , "Satellite perhaps" .)