The Conclave (a group that wants to stop humanity's expansion) was aware of the original position of Roanoke, and therefore was waiting to annihilate them. He further tells them that to isolate them fully, they are forbidden from using any advanced technology.
The Conclave, a group seeking to limit human expansion, was aware of Roanoke's initial location and planned to eliminate them. Moreover, he advised them not to employ any advanced technology to fully sever their connections.