How to Colonize an Asteroid
Energy for drilling the shaft into the asteroid will be supplied as concentrated sunlight. To concentrate the sunlight to usable levels, large free space mirrors must be erected in space near the asteroid to focus sunlight and thermal power into the areas where it will be needed. The materials for these mirrors will probably have to be manufactured after arrival, or maybe they could consist of large rolls of silvered mylar.
The mirrors will have to be mounted with provisions for steering and station keeping, possibly on tethers on the asteroid and blowing in the solar wind to keep them at the correct shape.