Project Apollo Achievement in Beyond Good & Evil HD
Pilot the spaceship to the moon
How to unlock Project Apollo
This is story related and cannot be missed.
Very close to the end of the game, you'll have to buy a space engine in order to complete the game from the Mammago Garage, it will cost 30 pearls and will be in the back of the room. After purchasing it or finally flying to the moon (a large portion of my friends got it at different times) the achievement will unlock.
WARNING: DO NOT fly to the moon until you have gotten all the pictures (except for a few of them that are in space), all the mdisks, all the PA1 units and all the pearls. As after going to the moon, anything on Hillys will be impossible to get and you will either have to load an old save or restart the game in order to re-gain them.