A MQ-9 Reaper used by the U.S. Air Force (example of a fixed-wing drone). (Image courtesy of U.S. Air Force/Staff Sgt. Brian Ferguson.)

It’s a bird, it’s a plane, it’s—a drone, the invasive new species that’s making itself quite at home in the world of the 21century. Though their explosion in popularity is fairly recent, drones have been around in one form or another for over 150 years.

In 1849, the Austrian army got the clever idea of putting bombs in unpiloted balloons and using them as a means of warfare; ever since then, drone technology has only gotten better.

Today, drones are used for a staggeringly diverse number of applications, with every indication that they’ll become more ubiquitous and capable as time goes on.





What is a Drone?

A DJI Phantom 4 quadcopter (example of a multirotor drone). (Image courtesy of DJI.)

Bomb-filled balloons, the earliest UAV. (Image courtesy of Jurij Drushnin.)

When you hear the word ‘drone,’ you probably picture some type of fixed-wing or multirotor aircraft, like the ones shown above (although luddites or apiarists probably picture a male bee, the drone’s namesake). However, the term is fairly broad. To understand the range of what a drone can be, it’s helpful to keep in mind its more technically kosher name: Unmanned Aerial Vehicle, or UAV (some people prefer Remotely Piloted Aircraft, or RPA, but we’ll stick to UAV).By this moniker, drones have a pretty clear-cut definition: they’re vehicles that fly through the air without an on-board pilot. However, unlike Austria’s bomb-filled balloons, drones today have the ability to be controlled remotely—that is to say, no drone flies alone.

All of the equipment needed to operate a drone—including external flight controllers, ground stations and the drone itself—can together be referred to as an Unmanned Aerial System (UAS). Exactly what’s included in a UAS, and how much external control is required, depends on the specific application.

So what are the applications of drone technology?

Let’s start at the same place as the Austrians in 1849: with drones of war.





Attack of the Drones

An MQ-1 Predator UAV used by the U.S. Air Force. (Image courtesy of U.S. Air Force/Lt Col Leslie Pratt.)

The tactical advantages of drones are immediately obvious. For one, the lack of a human pilot means you can complete a mission without putting any lives at risk. What’s more, no pilot means no need for a cockpit, so the size and weight of a UAV can be greatly reduced compared to piloted aircraft.

One use of military drones is to remotely launch weapons. Drones equipped with ordnance such as bombs or missiles are sometimes called Unmanned Combat Aerial Vehicles (UCAVs), and the use of UCAVs to destroy targets (including vehicles, buildings, and, well, people) is called a drone strike. These strikes are a tactic employed primarily (and with mixed public opinion) by the United States, although several other countries also have operational UCAVs.

But military drones aren’t just weapons of destruction. There’s plenty of engineering effort going into designing advanced non-combat UAVs, for tasks such as reconnaissance, surveillance and support. Take, for example, the Aerial Reconfigurable Embedded System (ARES) from the Defense Advanced Research Projects Agency (DARPA). ARES is designed for vertical take-off and landing (or VTOL, which means no runway required) using twin propellers that can rotate after take-off. Perhaps the coolest part of ARES is that it allows for interchangeable payloads, essentially making it a pair of wings on demand. Here’s a concept video from Lockheed Martin, which is manufacturing the prototype:

Another futuristic drone project courtesy of DARPA is research into Inbound, Controlled, Air-Releasable, Unrecoverable Systems (ICARUS). Project ICARUS is seeking to build low-cost UAVs that can deliver a payload and then literally vanish, using a clever combination of materials engineering and aerodynamic design.

Now you see it, now you don’t. (Image courtesy of Christopher Bettinger.)

With the rapid proliferation of military drones, it’s natural to wonder how one might defend against hostile UAVs. There are a lot of ideas in this arena, ranging from what you might expect (like shooting them down with lasers ) to the more far-fetched (like hunting them with eagles ).

Did I say far-fetched? I meant badass.

There’s even an upcoming drone demolition derby called DroneClash to help test and refine anti-drone technology. Drones in this derby will battle other drones as well as different anti-drone instruments, with teams competing to be the last drone flying (and if that sounds like fun to you, registration is still open).





A Drone of Your Own

The Airblock modular UAV. (Image courtesy of Airblock.)

Of course, drones are capable of much more than serving the military. Hobbyists have taken to drones in full force, using the technology to capture amazing aerial video s or just flying for the fun of it. And popularity with consumers is only rising—go into any electronics store and you’re sure to find at least a few drones on display.

Some drone pilots use first-person view (FPV) goggles to see everything their drone sees, making drone-flying like a real-life video game. Naturally, this has inspired an entire sport of drone racing, complete with its own governing bodies and world cups. This hobby is becoming increasingly accessible; for instance, in 2016, drone manufacturer DJI opened a purpose-built drone arena in South Korea, where interested pilots can learn the ropes and hone their flying skills.

The DJI drone arena in South Korea. (Image courtesy of DJI.)

For those who just want to learn about drones and try some low-key flying, one option is a Kickstarter project called Airblock , which offers an educational and easy approach to building your own UAV. Airblock is kind of like drone Lego—users snap together modular propeller blocks to form different configurations, and can program and control their drone with an app-based visual tool.

For consumers who want more complex drone designs, but don’t have the know-how to build them from scratch, MIT researchers recently developed a possible solution. Hobbyist drone builders simply input the specs they’d like their (multicopter) UAV to achieve, and the MIT system takes care of the hard calculations, enabling non-standard designs like a five-rotor pentacopter.

A five-rotor pentacopter designed with the MIT system. (Image courtesy of Jason Dorfman/MIT CSAIL.)

Maybe you just want to up your selfie game—drones can do that too. Another Kickstarter project called Selfly is an autonomous camera drone that snaps into your phone case, so it’s with you whenever you get the urge to take some high-up pictures or video.

Even consumers with no interest in operating their own drones can benefit from the technology. Take Amazon Prime Air, an Amazon program currently in development. Prime Air will use drones to deliver Amazon packages to customers in thirty minutes or less, making online shopping as immediately gratifying as brick-and-mortar.





Other UAV Applications

Drone images of a field in different light spectra reveal actionable information about crops. (Image courtesy of NASA.)

So far, we’ve only seen the tip of the drone iceberg—let’s dive deeper to see just how versatile drones can be.

Take agriculture, for starters. Since the earliest days of human civilization, we’ve been refining and improving our farming techniques. Drones are simply the latest agricultural innovation—equipped with infrared and other sensors, they can image fields to collect valuable crop data, or spray crops with fertilizers and pesticides. Drones have already been proven to significantly increase crop yields and mitigate crop losses, so don’t be surprised to see more and more drones working the fields in the near future.

In a similar vein, drone imaging is immensely useful for construction purposes. Drones can capture the necessary data to create detailed 3D models of construction sites, enabling massive time savings compared to traditional surveying, as well as increased site safety and easier planning capabilities. As with agricultural drones, this isn’t a far-out future concept—construction drones are being used right now, and are projected to be the largest use case for commercial drones in the immediate future.

As it turns out, having autonomous eyes in the sky is also incredibly useful for battling wildfires. Equipped with thermal and wind sensors, a fleet of drones can be used to monitor fires and coordinate response teams. "Drones can be a huge advantage to agencies fighting natural disasters," said Grant Imahara of Project First Responders. "They can launch immediately, gather vital data about an emergency situation and help efficiently relay that information to all agencies involved, all without putting further lives at risk."

The more you think outside the box of what a drone can be, the more applications open up. For example, Japanese drone manufacture PRODRONE has developed a drone that can cling to and crawl along surfaces. With its unique L-shaped airframe, this drone can adhere to both vertical and horizontal surfaces (such as bridges or other infrastructure) and roll itself along, inspecting the surface for damage as it goes.

Another innovative UAV from PRODRONE is equipped with a set of robotic arms that can grab and transport objects weighing up to 10 kg (22 lbs). Along with delivering cargo, such a drone could be sent into dangerous areas to retrieve hazardous materials, or be used in rescue operations like dropping a lifebuoy to a drowning person.





The Future of Drone Technology

It’s easy to extrapolate from current drone technology to envision a future where UAVs of all types—military, commercial, industrial, agricultural, firefighting, delivery, racing, photography, etc.—are a ubiquitous tool. But what else lies ahead for drones?

Here’s one likelihood: miniaturization. Micro Air Vehicles (MAVs) are an active area of study, with many designs taking inspiration from birds and insects. Consider DARPA’s Nano Air Vehicle (NAV) program, which resulted in a functional hummingbird-inspired drone appropriately called the Nano Hummingbird. Equipped with a camera, this drone weighs only 19 grams and has a wingspan of 160 mm, making it smaller than some actual hummingbirds.

The Nano Hummingbird. (Image courtesy of DARPA.)

A RoboBee drone, with a wingspan of 3 cm. (Image courtesy of Wyss Institute.)

Even more ambitious, the RoboBees Project from Harvard’s Wyss Institute for Biologically Inspired Engineering is bringing drones in line with their namesake, by developing MAVs based on the biology of bees. Each RoboBee weighs only 80 mg, and has wings built from artificial muscles that span a mere 3 cm and flap at 120 Hz. Eventually, swarms of RoboBees and other insect-sized drones (perhaps imbued with artificial intelligence ) could work together to accomplish many of the tasks discussed above, and more.Though MAV technology is still in its early stages, insect-scale, autonomous drones are expected to see increasing use within the next decade (though fans of the show Black Mirror may not be particularly excited by this prospect). Overcoming the engineering challenges of these drones is only half the battle—the legal regulations for drones will also need to be re-evaluated as the technology continues to evolve.

Whatever the pace of progress, drones are definitely here to stay.

What are your predictions for the future of drones? Leave your thoughts in the comments below.