<font color="yellow">Something like what I want, but the device only has a range of about 1-3 m. Perhaps the basic principle could scale, if the magnetometer booms were long enough... </font><br /><br /> I suspect the big deposits are going to be really big, like tens of miles in diameter. On Earth the big asteroid strikes get mixed & blended in by tectonic activity. On the Moon there has never been any. The big strikes are still intact, so a lump of iron that was a 5 mile wide asteroid would be all in the same spot & your metal detector can pick it up from much farther away without any enhancements. If you scale that up you should have no problem picking them up from a 60k orbit (low lunar orbit, LLO). If the technology can't be scaled up to detect at that range, hoppers powered by hypergolic engines might be just the thing you want to use. The search areas for the really big strikes can be reduced to the really big craters. When you find one that was an iron or PGM asteroid, start mining there. An iron asteroid 100 meters in diameter will be in the 5,000,000 ton range, so 1 mine site will go a long way. <div class="Discussion_UserSignature"> <font color="#993300"><span class="body"><font size="2" color="#3366ff"><div align="center">. </div><div align="center">Never roll in the mud with a pig. You'll both get dirty & the pig likes it.</div></font></span></font> </div>