When the older Doctor hinted to his companions that their next adventure involved the Apollo moon landing, they little guessed how deeply involved they would become with those events. From their first encounter with the impossible astronaut to their final stand off with the Silence, the moon landing - and the previously unknown story behind it - dominated the background of their adventure. The Silence, the Doctor reveals, has been manipulating the human race from the very beginning. They used humans to accomplish whatever task they desired. So when they needed a life support suit for the little girl, they inspired humans to travel to the moon and build the necessary equipment to accomplish it safely. One of the biggest accomplishments of the human race was nothing more than a means to an end for the plan of the Silence. Their manipulation techniques backfired on them, though. When Neil Armstrong first set foot on the moon, he triggered a video relay the Doctor had prepared, a video that showed a Silent apparently instructing anyone and everyone watching the moon landing to kill them all on sight. This unintentional post-hypnotic suggestion, in a classic Moffat twist, proved to be their undoing.