Economies of (Small) Scale: Exploring the Potential for Smallsat-Based Dexterous Robotics

While much interest currently exists in satellite servicing as a potential business endeavor, current flightproven robotic systems are large in terms of both mass and stowage volume, leading to high development, unit production, and launch costs. As a possible mitigation to this challenge, this paper examines the potential for lightweight dexterous robotic systems hosted on smallsat maneuvering buses (less than 50 kg), and built with as much low-cost technology as possible. Recent results are summarized for two parallel development projects at the University of Maryland: Exo-SPHERES, intended to provide external inspection and other servicing capabilities to the International Space Station; and DYMAFLEX, a Dynamic Manipulation Flight Experiment consisting of a smallsat with a lightweight (5 kg) high-speed dexterous manipulator to investigate algorithms for bus attitude control in the presence of rapidly maneuvering manipulators with moments of inertia similar to those of the bus. Between the two projects, relevant technologies have been developed and ground-tested to support the development and flight of a smallsat with two dexterous manipulators designed to have operational capabilities approaching those of an astronaut in a space suit.
Using the technologies underlying small dexterous manipulators and free-flying smallsat buses to support them, the paper summarizes several ways in which dexterous smallsat servicing vehicles could perform useful work in space, ranging from servicing and maintenance in low Earth orbit to commercial servicing of communications satellites in geostationary orbit. In-space docking and assembly would allow these systems to self-deploy throughout cislunar space after a secondary launch into a geostationary transfer orbit. The paper also summarizes recent experimental results in neutral buoyancy examining the utility of a small free-flyer in support of IVA and EVA crew at the International Space Station, and in support of EVA crew on the NASA Asteroid Redirect Mission.