How Drone Strikes Work

Militaries have been trying to attack one another with unmanned aircraft for more than 150 years. It all started in July 1849 when the Austrian army, after laying siege to Venice, tied bombs to balloons and floated them over the city. A timed fuse was supposed to release the bomb over the City of Canals, but, ironically, strong winds blew many of the balloons past the city and above Austrian encampments on the other side [source: Overy]. Both the Union and Confederate armies tried similar attacks during the American Civil War, but like the Austrians, their attempts were usually way off target [source: Garamone].

The Wright brothers' invention of piloted, powered flight in 1903 pushed drone experiments away from balloons and toward airplanes. The earliest prototypes, developed by the American military during World War I, were simply modified airplanes that could be pre-programmed to hit enemy targets. Despite some limited success, these early drones could not be recovered after an attack, and tests showed them to be too unreliable and imprecise for combat duty.

Shortly after the war, advances in radio control allowed unmanned aircraft to be guided in real time, and on Sept. 15, 1924, an American-designed Curtiss F-5L became the first aircraft to take off, maneuver and land by remote control [source: Keane and Carr]. Similar technology powered the U.S. Navy's remotely piloted Curtiss TG-2, which conducted the first successful remote torpedo attack during an April 1942 test strike on a practice warship [source: Grossnick].

Drones got even more effective during the Cold War. In the early 1960s, the Ryan Aeronautical Company developed the Lightning Bug, a reconnaissance drone that could be recovered by parachute. Later, the company adapted the design for a new weapon known as the BGM-34A. During a test flight on Dec. 14, 1971, this drone became the first to strike a target with air-to-surface guided missiles, earning its place in history as the first modern UCAV. While the Israelis successfully used the new drone against Egyptian armored vehicles and missile sites during the 1973 Yom Kippur War, it never saw action in Vietnam because the Americans felt it wasn't as good as manned technology [source: Clark].

The military continued to use drones throughout the end of the 20th century, but they were mostly reserved for reconnaissance missions. That's how the Predator drone got its start in 1995, but by Feb. 16, 2001, it was outfitted with Hellfire missiles — just in time for the U.S. response to the Sept. 11 terrorist attacks [source: Matthews].

After the terrorist attacks on Sept. 11, 2001, the United States government and its citizens were largely united in their desire to retaliate. But the question was: Against whom? Enter the Authorization for Use of Military Force (AUMF), passed by Congress on Sept. 18, 2001. Basically, the law gave the president permission to go after whatever country, organization or person was responsible for the attacks so they couldn't do it again.

Initially, the president used the authorization to strike al-Qaida, the group that carried out the attacks, and the Taliban in Afghanistan, who harbored them. Since then, however, AUMF has been used to justify everything from the Guantanamo Bay detention center to — you guessed it — drone strikes against suspected terrorists [source: Currier].

The first armed drone mission was carried out in Afghanistan on Oct. 7, 2001, and drones have been used during traditional military operations in Libya, Iraq and Afghanistan ever since. The more controversial strikes, however, have occurred in countries with which the United States isn't actually at war. These include Pakistan, which U.S. drones first hit in 2004, in addition to Yemen and Somalia, where strikes have been going on since 2011 (with the exception of one strike in Yemen in 2002) [source: Matthews].

Everything about drone strikes is a big secret. In fact, the Obama administration didn't even formally acknowledge the program until April 2012, and it rarely comments on specific strikes [source: Miller]. This secrecy makes it difficult to know for certain how many strikes there have been and how many people have been killed as a result.

The best data puts the number of strikes in Pakistan somewhere between 396 and 415, with 2,232 to 3,949 killed as of May 2015. Of these, somewhere between 262 and 962 were civilians [sources: New America, BIJ]. Yemen has experienced between 95 and 206 strikes, which killed between 65 and 158 civilians out of 447 to 1,117 total killed. Finally, nine to 13 strikes in Somalia killed a total of 40 to 105 people. It's estimated that up to five of those were civilians [source: BIJ].

The two armed drones in the U.S. arsenal are the ominously named Predator and Reaper drones. They actually look very similar, so it's not surprising that they share many characteristics. Both of these aerial weapons are propeller-driven, and both can be armed with laser-guided Hellfire missiles. Each is equipped with an antenna for communication with ground control during take-off and landing, while a satellite system is used to relay information when the drone is out of sight. This link goes both ways: The pilots can control the navigation, weapons and other systems on the drones, while the drones can send back information like images from its daytime and infrared cameras [sources: U.S. Air Force - Predator, U.S. Air Force - Reaper].

There are some significant differences, though. The Reaper is a bigger drone, boasting a wingspan of 66 feet (20.1 meters) versus the Predator's 55 feet (16.8 meters). With this size comes a number of advantages for the Reaper:

Of course, these advantages come at a cost: A drone unit — including four aircraft, a ground control station and a satellite link — costs $56.5 million for a Reaper versus $20 million for a Predator [sources: U.S. Air Force - Predator, U.S. Air Force - Reaper].

The Central Intelligence Agency (CIA) and an arm of the military known as the Joint Special Operations Command (JSOC) are both responsible for directing these armed drones, which are stationed at a series of secret bases across Europe, Africa and Asia and often flown by pilots who are actually in the United States. Initially, these agencies maintained "kill lists" consisting of suspected terrorists they targeted with strikes after receiving permission from the White House.

In 2013, however, the White House became more involved, working to formalize the process through what they termed a disposition matrix. This updated list, created by the National Counterterrorism Center, includes information on suspected terrorists like biographies, locations, associations and affiliated organizations. The list also includes strategies for how to deal with the terrorists, such as extradition, capture and drone strikes. Numerous high-ranking intelligence analysts and military officials review the list before it receives the final OK from the president. In the end, the president must approve all drone strikes outside of Pakistan; the CIA director can approve strikes within Pakistan [source: Matthews].

In 2013 President Barack Obama gave a speech justifying the drone program using three main points. First, he argued that terrorists are bad people who will try to kill Americans unless someone stops them. Second, he pointed out that terrorists like to hide in places where local governments have little or no influence, so the United States has to respond instead. Finally, he suggested that drones are the best of many bad options. Traditional air strikes are less accurate and more likely to cause collateral damage. Using Special Operations puts more American lives in danger, and invasions, as we've seen in Iraq and Afghanistan, can be difficult to contain [source: Fisher].

Not everyone agrees with that assessment, though. One of the most common criticisms is drone strikes sometimes kill innocent civilians; indeed, the highest estimates place civilian deaths at 1,125 in Pakistan, Yemen and Somalia as of May 2015 [sources: New America, BIJ]. In one such tragic instance in the Waziristan region of Pakistan in April 2015, a drone strike killed two hostages — one American and one Italian [source: Walsh]. The administration counters that while civilian deaths are regrettable, even more would die if the terrorists were allowed to live and carry out their attacks, not just in the United States, but also in the very communities where the drone strikes happen.

The other main criticism involves the legality of the strikes under both U.S. and international law. As we mentioned earlier, the Authorization for Use of Military Force (AUMF) gave the president the authority to attack those responsible for the Sept. 11 terrorist attacks. But 15 years later, with Osama bin Laden dead and al-Qaida on the run, many question whether the terrorists now killed by drones can really be linked to those original attacks. The administration justifies today's strikes by interpreting the AUMF to include "associated forces," though that phrase doesn't actually appear in the resolution. Perhaps most concerning to critics is that the Obama administration includes U.S. citizens in this group, meaning they can be killed without a trial. That's what happed to New Mexico native Anwar al-Awlaki — and his son, Colorado-born Abdulrahman — in Yemen in 2009 [sources: Global Justice Clinic, Currier].

Finally, numerous questions have come from the international community, including United Nations officials, who argue that drone attacks run afoul of international law. They contend that these rules prohibit killings in areas not recognized as being in an armed conflict. In response, the Obama administration has argued that the strikes are legal because they're carried out in self-defense [source: Bowcott].