Axel rover NanoDrill and PowderDrill: Acquisition of cores, regolith and powder from steep walls

This paper describes development and testing of low-mass, low-power drills for the Axel rover. Axel is a two-wheeled tethered rover designed for the robotic exploration of steep cliff walls, crater walls and deep holes on earth and other planetary bodies. The Axel rover has a capability to deploy scientific instruments and/or samplers in the areas of interest to scientists currently inaccessible by conventional robotic systems. To enable sample recovery, we developed two drills: NanoDrill for acquisition of 25 mm long and 7 mm diameter cores and PowderDrill for acquisition of either in situ regolith/soil or drilled cuttings from depths of up to 15 mm. Both drills have been successfully tested in laboratory in limestone and sandstone rocks and on-board the Axel rover in the Mars Yard at NASA JPL. The drills managed to acquire limestone and sandstone cores and powder, with an average power of less than 5 Watts. The penetration rate of the NanoDrill was ~2 mm/min and of the PowderDrill it was ~9 mm/min. After sample acquisition, both drills successfully ejected of the acquired samples (cores and powder).