How do you think the Infinity happened to find Requiem? Also, do you think Forward Unto Dawn just drifted to Requiem or do you think it got there by intervention similarly to the Spirit of Fire got to the Ark?
[i]"A science team got zapped excavating a Forerunner artifact. This... sensor data was all that was left. And our geeks managed to pull some coordinates. I'll give you three guesses where it led."
-Andrew Del Rio[/i]
The process of excavating the Composer sublimated a science team, leaving behind coordinates to Requiem.
It got there by intervention. Mendicant Bias at the end of Halo 3 clearly states he's sending the Chief to his makers.