The Inchworm Deep Drilling System (IDDS) concept evolved to allow for interplanetary deep drilling without the need for a large drill rig. The 7′ long drill has two “feet” that allow it to preload itself against a launch tube or borehole wall by extending radially, then use this preload to drill down. When the drilling thruster reaches the end of travel, the feet contract and inch farther down the hole, similar to how an inchworm moves. I was in charge of the foot design. Three synchronized lead screws drive a custom nut along the axis of the drill, which acts on wedges to push out three “toes” on each foot that exert force on the borehole wall. Because required drilling power expands with the square of the radius, the main challenge was keeping all the necessary hardware, wire harnessing, and switches within the target 4″ diameter.