Drone Wars: Science Meets Science Fiction

The military now operates a fleet of 195 Predators and 28 Reapers. Meanwhile, the U.S. has stepped up its use of remote-controlled drones to carry out missile strikes over Pakistani territory to find and kill Islamist extremists. (They are also being put to use to monitor the U.S.'s southern border with Mexico.

In the accompanying photo, the MQ-1B Predator, a long-endurance unmanned aircraft system that conducts close-air support, air interdiction, and intelligence, surveillance and reconnaissance missions.

Speaking about the military's increased use of UAVs, Army Col. Christopher Carlile told an army aviation forum earlier this year: "There's an old saying that science and science fiction is only separated by timing - and that timing is now. We have it."

The United States considers the northwestern tribal region of Pakistan, which borders Afghanistan, a haven for Islamist militants who use the lawless area as a base to plan and carry out attacks on NATO and Pakistani forces. A record number of strikes by U.S. drones have killed more than 150 people since September 3. However, the attacks have raised tensions with Pakistan. The accompanying photo was taken at a protest in Lahore, Pakistan on Oct. 21, 2010, in which Pakistani NGOs protested American strikes carried out by the air force's unmanned aerial vehicles.

A more heavily armed successor to the Predator in flight. The upgraded drone, manufactured by General Atomics Aeronautical Systems of San Diego, is supported by a ground control station, a satellite communications terminal and 55 personnel.

In flight, this UAV and its on-board sensors are controlled by the ground crew with a direct data link. When the craft flies beyond the range of a direct link, the ground crew maintains control though a satellite data link. Although its primary function is for intelligence, surveillance and reconnaissance, it can launch Hellfire anti-tank missiles

U.S. Air Force photo/Staff Sgt. James L. Harper Jr.

An Air Force MQ-9 Reaper taking off from Kandahar Air Base, Afghanistan. The Reaper was designed to be a medium-to-high altitude, long endurance unmanned aircraft system. It features a series of infrared sensors as well as a laser rangefinder/designator which provides the capability to designate targets for laser-guided munitions. The craft is also made by General Atomics.

The MQ-9 Reaper is larger and more powerful than the MQ-1 Predator. It was designed to attack time-sensitive targets. The "M" is the Department of Defense designation for multi-role while "Q" refers to unmanned aircraft system. It was the ninth in the military's series of remotely piloted aircraft systems.

The MQ-1 Predator is a medium-altitude, long-endurance unmanned aircraft system. The fully operational system consists of four air vehicles (with sensors), a ground control station and a Predator primary satellite link communication suite.

An RQ-4 Global Hawk sits on the runway before beginning a nighttime mission. The aircraft is unmanned, and is used to capture imagery from high altitudes.

A MQ-9 Reaper on a training mission. In the last four years, the use of unmanned aerial vehicles by the air force has increased from roughly 165,000 hours to more than 550,000 hours annually.

Technician secures a guided bomb unit-12 Paveway II laser-guided bomb onto the munitions rack of an MQ-9 Reaper

Air Force technicians prepare to load an AGM-114 Hellfire II air-to-ground missile onto a MQ-9 Reaper.

An officer remotely pilots the MQ-9 Reaper at Kandahar Airfield, Afghanistan.

Reaper pilot in training.

A MQ-9A Reaper unmanned aerial vehicle prepares to land after a mission.

An armed MQ-9 Reaper unmanned aerial vehicle taxis down a runway in Afghanistan. The Reaper has the ability to carry both precision-guided bombs and air-to-ground missiles

Reaper lifts off on training flight.