Today’s mobile robots are severely limited by the energy capacity of the conventional batteries used to power their motors and actuators. But robots may soon take off, thanks to a team of engineers led by Michael Goldfarb and Eric Barth at Vanderbilt University. The researchers have built a novel robot actuator that runs on rocket power. For fuel, the simple, lightweight design uses liquid hydrogen peroxide stored at high pressure and mixed with a catalyst. The ensuing chemical reaction releases a flow of oxygen gas and hot steam that drives a piston. A robot arm hooked up to this rocket-propelled piston can repeatedly lift a 23-kilogram load five times longer than today’s best batteries and electric motors. Once developers have optimized both the hardware and the fuel, says Goldfarb, the rocket-powered actuator could pack 10 to 40 times the energy of a conventional actuator of similar size. That’s an improvement that would radically change the way robots are designed and used, according to Goldfarb. Vanderbilt has filed an application for a patent on the technology, and the actuator could be commercially available within the next three years.