Military Drones Present And Future: Visual Tour

Militant leader Mullah Nazir and several Taliban fighters were killed by the attack, which involved at least two missiles, according to reports.

The Department of Defense and U.S. intelligence agencies are increasingly using UAVs for everything from battlefield surveillance to remote-controlled strikes against terrorists. Such strikes have also been blamed for civilian casualties in their pursuit of enemy targets.

And drones aren't limited to overseas operations. Military flights are increasingly taking place over U.S. skies, raising privacy and public safety issues, according to a new report from the Electronic Frontier Foundation. When one of the Air Force's MQ-9 Reapers, described as "hunter, killer" drones, crashed in Nevada last month, a spokesman expressed relief that no one was hurt.

The Army and the Air Force are developing "sense-and-avoid" systems that will let military UAVs share U.S. airspace with commercial and private planes by automating how they maneuver. One such system will use cooperative sensors that work with the Traffic Collision Avoidance System used in civil aviation and with the FAA's Automatic Dependent Surveillance-Broadcast (ADS-B) system. Another is an optical system that looks for other aircraft and provides tracking information to a computer on the UAV.

The Navy plans to begin deploying UAVs on aircraft carriers. The U.S. Navy last month lifted a Northrop Grumman drone, the X-47B Unmanned Combat Air System, onto the USS Harry S. Truman. The X-47B is capable of flying preprogrammed missions, then returning to the carrier for landing. Its initial application will be refueling other aircraft while in flight, but the X-47B can also carry and fire weapons.

Other countries are developing or buying their own UAVs. Britain's Royal Navy recently tested a drone that could potentially be used from its ships, according to The Guardian. There's always the risk that a U.S. drone will fall into the wrong hands. A few weeks ago, Iran claimed to have captured a U.S. Navy drone that had entered its airspace. Navy officials denied that it was theirs.

Military drones range from lightweight flying machines that can be launched by hand, to the Air Force's 11,000 pound X-37B, which is about one-quarter the size of NASA's space shuttle. The X-37B, pictured above, took off on an Earth-orbiting mission on Dec. 11, a secretive project that will test the feasibility of long-duration military space flights.

The "reusable space plane" was launched from Cape Canaveral, Fla., on an Atlas V rocket by the Air Force's Rapid Capabilities Office, which develops combat support and weapons systems. The X-37B is dwarfed by the rocket and fairing used to lift it into space. From top to bottom, the whole system is 196 feet long. The X-37B itself is 29 feet long and 10 feet high.

The Pentagon has used UAVs for more than 50 years. Some, like General Atomics' Predator, have established their utility through years of service, but new designs, such as UAVs equipped with laser weapons, keep pushing the boundaries on what drones can do. Following is our guide to U.S. military drones in their many shapes and sizes.

Image credit: Air Force