Pneumatic Sampling in Extreme Terrain with the Axel Rover

Abstract

Some of the most interesting regions of study in our solar system lie inside craters, canyons, and cryovolcanoes, but current state-of-the-art rovers are incapable of accessing and traversing these regions. Axel is a minimalistic rover designed for extreme terrains, and two Axels with a central mother system form a four-wheeled rover to efficiently traverse flat ground. Upon approaching the edge of a crater, Axel detaches from the mother system and travels down the cliff guided by the unwinding tether. However, scientific study of extraplanetary terrains requires instrumentation inside the Axel rover. We aim to develop a simple and reliable sample acquisition and caching system that could retrieve multiple samples from various sites before returning them to the mother system where more sophisticated instruments could perform further analysis. For simplicity and robustness, we propose a pneumatic sampling system which uses compressed air, guided with a nozzle, to blow soil into a sample canister. Numerous types of nozzles were designed, built, and tested. Different designs for nozzle deployment, sample caching, and pressure containment were considered. Finally, a prototype of the entire sampling system was built and evaluated for performance and feasibility.