Thanks that was indeed helpful, I have a question in regards now to geo survey buoys/probes. If a geo-probe has a range of say 4bil km does it "die" when it reaches its target asteroid or does it just float on site doing its job. Also in regards to buoys, I assume a missile firing control is required but seeing as it has no range per say the worst MFC in all history can be designed to achieve the "drop" of the buoy. The wiki doesn't offer much in the way of info in regards to buoy's, just a brief tutorial on how to design them.