July 31, 2012: The U.S. Army is testing a laser that can recharge the batteries of small UAVs while they are in flight. Initial tests with the Stalker UAV have been successful. This sort of capability would aid Special Forces troops on long range patrols who depend on small UAVs to help them track the enemy. For the last six years U.S. Army Special Forces has been using a special UAV (Stalker) developed for them to aid recon patrols searching for Taliban leaders and technical specialists out in the back country. The 6.4 kg (14 pound) aircraft is made of composites, has a three meter (ten foot) wingspan, and is launched by throwing. Stalker has a two hour endurance and can fly as high as 4,800 meters (15,000 feet). Using batteries, and a special "quiet" propeller, the aircraft is optimized for going high enough to be unseen and unheard. It's perfect for stalking someone. The UAV is broken down into components that can be easily carried, along with spare batteries and different sensor modules (day, night, low light). Stalker also carries a laser designator, enabling it to tag weapons for laser guided bombs.
Stalker replaced the smaller Raven (still used by the U.S. Army) with many SOCOM operatives. Raven weighs less than half what the Stalker does but has only 45 minute's endurance. Even with two hours per flight, the Special Forces needed three Stalkers to keep one over the suspects for longer periods. These stakeouts can go on for days before the Special Forces operators are able to confirm the identity and location of their target. The laser "refueling" system might be a solution but maybe not. The army is now conducting realistic field tests. This sort of thing often reveals excellent ideas to be impractical in the real world. A recent test using a Stalker staying aloft in a wind tunnel kept the UAV airborne for 48 hours.
