Snow White and the 700 Dwarves

Abstract

Detailed scientific study of possible sites on Mars such as extinct hot springs may require robotic excavation of the sort generally associated with archaeological “digs” on Earth. This paper describes a system developed to explore the feasibility of building such a robotic network. A scaling analysis shows that, for a given landed mass, it is better to break the payload into as many small vehicles as possible, due to the surface-to-volume implications on the power-to-weight ratio for the system using solar power. Each small vehicle must be equipped with a shovel and hopper to move loose material, and a provision for a percussive hammer to break up hard soils and rocks. A central mast rising from the nearby lander supports stereo imaging and a computer providing central co-ordination of activities. Each vehicle has limited sensing (e.g. no vision) but is designed to follow simple commands (goto(x,y)) and rules (keep to the right of oncoming traffic). The outer surface of each vehicle is arranged to capture solar energy, and the lander mast can be configured with a foil reflector to bounce sunlight down into the excavation to keep the vehicles powered most of the day. Thus we have a system consisting of a single tall mast with a pair of stereo cameras at the top and a large, silver reflector hanging down, together with a large number of small robots, each having a pick and shovel. This system has been dubbed “Snow White and the 700 Dwarves”.