An experimental investigation of robotic spacewalking

Abstract

NASA's human space flight program depends heavily on spacewalks performed by human astronauts. These extra-vehicular activities (EVAs) are risky, expensive and complex. In collaboration with the Defense Advanced Research Projects Agency (DARPA), NASA is developing a robotic astronaut's assistant called Robonaut that can boost EVA productivity while reducing risk and conserving EVA resources. Robonaut is an anthropomorphic robot equipped with human-like dexterous manipulation and microgravity locomotion capabilities. Robots are proposed as cost-effective, energy-efficient tools supporting humans on extended space missions, riding aboard orbiting spacecraft and transit vehicles en route to Mars, the moon and other destinations. Spacewalking is poorly named, as it has little in common with how animals walk on Earth. In order to move about in a microgravity environment, a robot must be able to climb autonomously, using gaits that smoothly manage its momentum and that minimize contact forces while providing for safety in the event of an emergency requiring the system to stop. A one-g robotic mobility test is conducted with Robonaut floating on air-bearing equipment that emulates the dynamics of weightless motion and allows the robot to translate under its own power. Test results are presented for a simplified EVA task.