Researchers say they have taken undersea robotics to subsequently level, effectively running independent robotic vehicle off Hawaiian Islands for over three months, powered only by energy attached from modifications in sea temperatures.

Sounding Oceanographic Lagrangian Observer Thermal Recharging vehicle is product of years long joint research project by NASA, U.S. Navy, and Scripps Institution of Oceanography, and University of California at San Diego. Group said Solo-Trec is first vehicle to power totally by ocean's thermal energy.

Solo Trec functions by taking benefit of temperature vary as it moves among heater, lower regions to cooler temperatures. It's ready with ten exterior tubes of waxy objects called phase-change material. In heat of low waters, material melts and enlarges; in deeper waters, it cools, solidifies, and contracts. Expansion caused by hot temperatures pressurizes oil in device, which drives hydraulic motor that, in turn, recharges Solo-Trec's batteries. This system permits 183-pound vehicle to make over 300 dives from ocean's surface to depth of 1,640 feet and powering its optimism controls and scientific, GPS, and communication instruments.

"People have extended vision of machine that generates extra energy than it uses and runs for ever," said NASA's Jack Jones. "As not true continuous motion system, as we really use ecological energy, model system verified by Jet Propulsion Laboratory and partners constantly observe ocean without limit on its lifetime imposed by energy supply." Now, Solo-Trec is prototype; its work is to assist scientists assess possible for controlling upcoming research crafts in similar way. But NASA says similar equipment utilized to make convoy of independent bots able of Journey Sea and observing from weather and sea life to mapping land and conducting undersea inspection.