The Stinger: A Geotechnical Sensing Package for Robotic Scouting on Small Planetary Rovers

Abstract

Flawless operation of mobility systems, excavation, mining and in situ resource utilization (ISRU) operations, regolith transport, and many other activities critically depends on knowledge of the geotechnical properties of the soil in a given area. Various terrestrial tools can be used to assess in situ properties like soil strength and its density (and in turn fundamental soil parameters: friction angle and apparent or true cohesion), but few of these tools have been successfully adapted to planetary exploration. To meet this need, Honeybee Robotics has combined the capabilities of the penetrometer used during the Apollo program with a Lunokhod-inspired shear vane to create their Stinger instrument. Its probe tip, designed after the cone of a static cone penetrometer, allows for continuous bearing strength measurement as it is steadily fed into the ground. A shear vane is initially housed inside the cone tip of the probe so that the vane will not affect cone measurements. This vane can then be deployed at any depths of interest up to 50 cm to conduct a shear test, and subsequently retracted for further cone penetration. Stinger performance has been validated to TRL6 through testing in various lunar and Martian simulants as well as in the Atacama Desert in Chile while mounted to a NASA-developed rover.