Low-cost robotics for space exploration: a probabilistic trade space for biomorphic exploration devices

Numerous in-situ sampling missions are planned to a variety of planets, moons, asteroids, and comets. Among the variety of new technologies needed for such exploration are small, highly mobile, autonomous and relatively inexpensive platforms known as biomorphic explorers. These miniaturized robotic devices will be particularly valuable for study and exploration of the surfaces of planets, moons, and small bodies. Large numbers of small, dexterous explorers could seek out and deploy sensors in places not accessible by larger rover vehicles or landers. The low cost of such microdevices would also enable the exploration of heretofore high-risk and dangerous landing sites excluded by large, more expensive systems. This paper addresses the problem of determining the tradeoff space between the likelihood of each device achieving its stated science goal and the number of units needed to obtain the minimum required mission probability of success. Probabilistically, to a first order, the paper addresses the question, "if the probability of a single unit achieving its goal is x%, what is the required number of units to achieve 95% probability of mission success?" The impacts of cost are discussed using a linear fixed and variable cost model to derive the optimum number of units for deployment. The issues relevant to the analysis and deployment of multiple, low cost, microelectronic and electromechanical devices (MEMs) biomorphic explorers and the corresponding risks are also presented. A simple decision tree is presented with a parametric cost model to illustrate the potential to address risk and cost trade-offs. Three-dimensional visualizations of the probabilistic trade space are presented to illustrate these issues.