Stories about superhuman strength permeate popular culture from Atlas to Zeus, Superman to Schwarzenegger. But now, says University of Utah robotics expert Stephen Jacobsen, it's time to deliver in the real world. With funding from the U.S. Department of Defense, Jacobsen's Salt Lake City-based company, Sarcos, has built a robotic suit that does just that. A person wearing this powered "exoskeleton" on his or her legs can carry massive loads without getting tired. Exoskeletons could enable soldiers to haul heavier equipment over greater distances, allow rescue workers to carry survivors more safely, and eventually help disabled people get around. It's a daring vision-and Sarcos is hardly the first group to pursue it-but Jacobsen seems a good bet to do it right. Over the course of his career, the prolific inventor has developed standout devices that include the world's leading powered prosthetic arm and the dancing fountains of the Bellagio hotel in Las Vegas-all using the most advanced robotics technologies available. And while it may take years to make exoskeletons practical for widespread use, Jacobsen says, "before you do it right, you have to do it at all." This spring, he gave TR associate editor Gregory T. Huang an exclusive tour of Sarcos and showed how the company goes about building a wearable robot.

1. Sensor suit. Jacobsen walks into a bustling hangar-like hall and points out a yellow contraption the size of a person. The first step in designing the exoskeleton, he explains, was building this plastic mock-up of the device that designers could use to gather data about how the human body moves. Volunteers donned the suit, and its 30 position sensors measured the range of motion and timing of each joint as they walked, ran, jumped, twisted, and squatted. The data were used to help create a computer model of the exoskeleton.

2. Mini model. But to see how various designs will work, it helps to build physical models too. In an equipment room down the hall, designer Jon Price positions a miniature wooden model of the exoskeleton next to a quarter-scale clay sculpture of a person. This setup, he says, allows researchers to see whether the machinery around a joint will bump into itself, for instance. "You build and you analyze, hand in hand," says Jacobsen. And it's a lot easier to make changes to the design at this scale.