My daughter and I are debating whether it is technically feasible to bring a nickel iron asteroid to the surface or the earth non-destructively. I felt it was impossible. Her thought was that with a propulsion system like M2P2 (already on the drawing boards) that would act on the entire ferro-magnetic body at once so as to avoid breaking it up, and a long enough time to fiddle with its orbit, one could put it in an elliptical solar orbit whose aphelion precisely matched the position, rotational velocity, and orbital velocity of some spot on the surface of the earth. With a big enough chunk, atmospheric effects would be tiny.
This would not exactly be a Hohmann transfer orbit to earth from the vicinity of Mercury, but would be similar in concept. After some thought, I granted that it might be possible but calculating the orbital mechanics would be tough slogging and I am pretty sure the required precision is not currently available in any propulsion system. The earth is also not perfectly round and the thing would probably have to bash through a couple of mountain ranges before coming to rest unless the whole last bit of its orbital spiral was over an ocean.
The question remains though. If we had the time, computing power, and precision thrust, could this be done? Imagine a few kilometer high piles of nickel iron (with very interesting impurities) in isolated spots around the equator. The impact on industry, science, the economy and human life in general would be profound.