Apollo launch (8)
I believe the answer is:
moonshot
'apollo launch' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for moonshot that I've seen before include "Ambitious launch" , "Rocket launch to our nearest neighbour" , "Space flight" , "Launching of a lunar spacecraft" , "Launch of spacecraft to Earth's near neighbour" .)