United States' Defense Advanced Research Projects Agency (DARPA) is building a submarine that will never run out of power. According to a recent report in Forbes, the defence agency has given contracts to a company named Northrop Grumman Systems Corporation and Martin Defense Group to build a demonstration version of the new unmanned underwater vehicle, named Manta Ray. In order to achieve the indefinite power supply, DARPA has awarded a contract to Metron for the submarine's energy-harvesting system to power it indefinitely, allowing it to carry out missions lasting months or years without having to return to base or refuel.
According to the Manta Ray website, the project will demonstrate key technologies to enable a class of "long duration, long range, payload-capable” robot submarines, capable of “persistent operations in forward environments." Reports suggest that the Manta Ray could be able to carry anything from a small towed sonar array for submarine detection, to acoustic sensors for placing on the seabed, to electronic warfare equipment. This is the second round of funding for Manta Ray after contracts were awarded last year, suggesting that the program is on schedule.
DARPA says that Manta Ray will have AI capabilities to identify and respond to other vessels and submarines, along with other new sensors. The biggest challenge for DARPA, however, will be the power. Manta Ray is said to provide for greater endurance as compared to other robot submarines as Manta Ray aims to harvest energy from the sea to recharge itself - one of the reasons for the unusual shape of the submarine. It needs minimum drag to make the best possible use of limited power reserves. The unusual shape will also make the submarine stealthy.
A report in Forbes said that energy harvesting concept has already been proven for the a US Navy unmanned vessels like the Wave Glider boats. These vessels use a combination of solar power and wave energy for propulsion and to power their electronics. However, powering underwater vehicles can be more challenging, as underwater vehicles do not have access to solar or wave energy. Nevertheless, there are methods like Thermal Engine, thermoelectric modules, and the likes.
Previous images of the Manta Ray suggest another power source for the submarine. An image shows the submarine anchored to the sea bed with a wire, while a smaller vehicle glides above it. This was the "Underseas Kite" developed at North Carolina State University, according to the Forbes report. Just like power generation kites are developed as an alternative to wind turbines, the device uses the different flow of water at different altitudes to generate power.