Hi A Silent Poop, Achievements sometimes have a delay in unlocking for a number of possible reasons. Assuming you've met all the requirements for the achievement, I first recommend signing out of your Xbox/PSN account, restart Destiny, and sign back in when prompted. As well, you may also wish to try signing into your character, logging out of Destiny, and pressing start at the launch screen when prompted to do so. Finally, networking issues may cause a delay in the appearance of an achievement, so if you've yet to see it, it may appear at a later date.