In a move to make military logistics simpler by eliminating the need to move fuel and batteries around battlefields, the US Army has awarded Raytheon a contract to develop a directed energy wireless power system that can beam energy to where it's needed.
If you've ever seen images of armies in the field, it's easy to forget that each soldier is the sharp tip of a very long logistical spear made up of a huge number of people and a lot of materiel. This means that soldiers can only move forward so far so fast. If they move too fast, they can easily end up outrunning their supply lines and quickly run out of food, ammunition, medicine, and, most important, fuel and power sources.
The average US soldier today carries up to 140 lb (64 kg) of gear on their back – and a lot of this is in the form of batteries to run their equipment. Squaddies famously don't like these heavy batteries and tend to 'lose' them as soon as possible.
In addition, vehicles need fuel as do the increasingly sophisticated electronics and directed energy weapons which can rely on it for power. This means supply lines must be secure and convoys regularly deployed that need fuel to carry the fuel, which means more fuel is needed to carry that fuel.
Not only are such logistics massively difficult to maintain, they also pose a security risk for concealed forward units. It's a bit like sitting in a carefully camouflaged hide to watch a rare bird and then have a pizza delivery truck roll up with the radio blaring.
The idea behind the new Army contract under the Department of Defense's Operational Energy Strategy is for Raytheon's Advanced Technology team to replace much of these supply lines with beams of high-energy coherent microwaves that are transmitted from a secure generator to forward positions where it's converted back into electricity.
The idea of wireless power isn't new. It's been around since the days of Nikola Tesla and has been regularly revived with the dream of whole cities plucking energy out of the air like a radio broadcast. Unfortunately, the laws of physics make such a thing completely impractical and the closest thing we have to such a thing today are the wireless chargers used to top up smartphones and smart watches.
However, these chargers work by induction and, therefore, at extremely short range. What Raytheon is working on is something that can work at long and even very long range. It's based on a technique developed at Raytheon by William Brown in the 1950s when he realized that microwaves could be used for more than radar and communications. With sufficient scaling they could be a way of transmitting power from one point to another.
This resulted in a series of demonstrations, with one in 1975 transmitting 475 W of microwave power across a distance of a mile (1.6 km) and then converted to DC electricity with an efficiency of 54%. At least one commercial system has been developed in New Zealand as a way of sending power to remote communities.
The new Raytheon system is intended to make energy uniformly available across the battlefield, directly powering sensors and eliminating the need for fuel depots. Though vehicles will still need to top up if they're using fossil fuel engines, beaming power will reduce the demand because it would replace generators as the primary power source.
In addition, the microwave connection can also be used as a secure communications channel. Also, by selecting the proper microwave frequency, the beam would be safe for humans or animals that might accidentally step in the way.
"Wireless power and data can provide enhanced capability in the future manned and unmanned teaming battle space," said Colin Whelan, president of Advanced Technology at Raytheon. "This is extremely important in highly contested threat environments where operations are challenged."
Source: Raytheon