Two companies, Lockheed Martin and LaserMotive, have managed to keep the Stalker Unmanned Aerial System, also known as a drone, in flight for over 48 hours by using lasers on the ground to recharge the aircraft's battery mid-flight. So ... that's terrifying and cool. LaserMotive held the test in an enclosed wind tunnel, (the next step is an in-field test), and if you're wondering what happened after 48 hours, well, it seems they just got bored. From LaserMotive's press release:

At the conclusion of the flight test, held in a wind tunnel, the battery on the Stalker UAS had more energy stored than it did at the beginning of the test. The test was concluded only because the flight had already surpassed the initial endurance goals set by the team

You know, you try to raise a drone the best you can, but pretty soon it stops coming home and then it just stops calling—Oh, sorry. Anyway, the technology would allow a drone to sense when its battery is low and use GPS to return to an area where the laser could recharge it. If all this sounds implausible to you, check out this year-old demonstration video during which a helicopter device with a laser aimed at it stays aloft for 12 hours. It's a slightly different test, but it'll give you an idea:

Though drones are most famously used for military purposes, and Lockheed Martin noted that this technology will eventually allow their Stalker drone to go on lengthier missions, the company sees it applying to other situations. "Maybe it's police, maybe it's fire, maybe it's emergency services. If they need to be up overhead for a long period of time, that makes a lot of sense to put a system like this in place," Tom Koonce, the project manager for Lockheed Martin, tells CBS Los Angeles. Sure, police purposes, fire purposes, robot war against humanity purposes ... What? We're not scared. You're scared!