There have been many drones with some of the most jaw-dropping features. With the ever-changing technology, everything we know about drones keeps on changing and evolving. Drones are known to have a short battery life. Most of the commercial drones can fly from 30 minutes to an hour (depending upon the type of drone) on a single charge. After its stipulated time, the drone is compelled to shut down and recharge. Military grade drones may take it several notches higher as they can stay in the air for several hours together. However, even they run out of charge and have to land for refueling. From the biggest to the smallest, all UAVs come with their limitations.
The U.S army is in a constant attempt to break this limitation and has been working on a technology that may make it possible for drones to stay in the air forever. This technology operates around the use of lasers. The way this works is that the operator shoots a high-intensity laser from the ground aimed at a photovoltaic cell (solar cells) present on the body of the drone. The energy from the laser is absorbed by the photovoltaic cell and converted to electricity, this in turn powers up the drone and can allow it to hover for an indefinite amount of time. This project is being undertaken by DARPA (Defense Advanced Research Projects Agency) which is an agency of the United States Department of Defense responsible for the development of emerging technologies for use by the military. They call this technology the Stand-off Ubiquitous Power/Energy Replenishment – Power Beaming Demo (SUPER PBD).
DARPA reckons that they may be able to achieve this kind of mid-air drone recharging from a distance of 6.8 miles (11 Km). They have chosen the Silent Falcon drone as the optimum drone for its trials and are working on developing the technology for it.
Like any other new invention, this one also faces many hurdles. Without overcoming these crucial challenges, the laser powering system is as good as fiction.
The laser which would be used in this project is of high intensity and the biggest threat is of excessive heating caused by the laser. When the solar cells receive the laser beam, not all of it is converted into electricity. The remaining of the energy from the laser is transferred as heat and if not controlled it can even melt the drone. Therefore, if they can manage to dissipate the excess heat, it might help overcome the biggest obstacle.
Real World Environment
DARPA states that the laser powering system may be able to work from a distance of 6.8 miles but considering the nature of lasers that may or may not work efficiently as the further a laser beam goes, the more it loses its intensity and tends to become weaker. Moreover, lasers have difficulty navigating through real-world environments like fog, rain, smoke, etc. Such natural obstacles can easily block lasers hence that may also need some looking after.
Damage to the Environment
The laser system as mentioned would be operated from the ground and from a far-off distance. Therefore, if the laser is not aimed exactly at the photovoltaic cells of the drone, it may pose a threat of damaging other surroundings. It may cause forest fires in a natural habitat or if used for commercial drones within the city, the risks are uncountable.
Currently, the Army is working to power drones on the ground before using this technology for mid-air recharge. They aim to achieve this feat by early 2019. Once powered on the ground they plan on starting trials to power drones via lasers during flight in 2020. Gradually, they intend to resolve the hurdles and with appropriate regulations make their laser-powered drones ready for take-off.