Private coach starts to travel using the orbital road (5)
I believe the answer is:
tutor
'private coach' is the definition.
'starts to travel using the orbital road' is the wordplay.
'starts to' says to take the initial letters.
The first letters of 'travel using the orbital road' is 'TUTOR'.
(Other definitions for tutor that I've seen before include "School" , "Master" , "Edify" , "Coach, teacher" , "class leader" .)