In 13 short years, killer drones have gone from being exotic military technology featured primarily in the pages of specialized aviation magazines to a phenomenon of popular culture, splashed across daily newspapers and fictionalized in film and television, including the new season of “24.”

What has not changed all that much — at least superficially — is the basic aircraft that most people associate with drone warfare: the armed Predator.

The Predator, with its distinctive bubble near the nose and sensor ball underneath, is the iconic image of drone warfare, an aircraft that grew out of 1980s work supported by the Pentagon’s future-thinking Defense Advanced Research Projects Agency.

Originally developed to perform surveillance, the CIA added Hellfire missiles and began using the Predator to hunt down members of the Taliban and al Qaeda after the US invasion of Afghanistan in 2001. Though the CIA and Air Force now fly an updated version of the Predator — named Reaper — the drone is still relatively easy to detect, and easy to shoot down, at least for a country with a modern military.

In fact, as terrifying as drones sound, they actually aren’t all that sophisticated compared to other weapons in the US arsenal. The original Predator plodded along at a pokey 84 miles an hour.

Its missiles, though lethal, are decades-old technology developed to destroy tanks, not terrorists. And despite concerns about autonomous killing machines, the Predator must be operated by a pilot (albeit remotely). The Predator has proved effective, but it is not exactly the sci-fi miracle that many might imagine.

Under development, however, is a new generation of drones that will be able to penetrate the air defenses of even sophisticated nations, spotting nuclear facilities, and tracking down — and possibly killing — terrorist leaders, silently from high altitudes. These drones will be fast, stealthy and survivable, designed to sneak in and out of a country without ever being spotted.

In fact, the Predator may someday be to drone warfare what the V-2 was to long-range ballistic missiles: a crude, but important, first step in a new era of warfare.

The Past

1980 — The Defense Advanced Research Projects Agency (DARPA) launches “Teal Rain,” a top-secret study on high altitude, long endurance unmanned aircraft.

1984 — DARPA contracts with Abe Karem to design a UAV (unmanned aerial vehicle) called “Amber.”

1990 — General Atomics buys Abe Karem’s company, Leading Systems. It sells Karem’s UAV, now called “Gnat,” to the CIA. In 1994, General Atomics is given contract to develop the Predator, a successor to the Gnat.

1990s — Pentagon secretly funds development of an unmanned successor to the SR-71 Blackbird (a stealth plane introduced in 1964 and famous in popular culture; it’s even used by the “X-Men”). Boeing, Northrop Grumman and Lockheed compete.

1998 — Retirement of SR-71 Blackbird. The Pentagon pursues two new spy drones: the Global Hawk, a high-altitude surveillance drone, and the RQ-3 DarkStar, a stealthy spy drone, which crashes and is cancelled.

2001 — October 7: First armed Predator strike in Afghanistan. The CIA attempted to kill Taliban leader Mullah Omar.

2007 — General Atomics delivers the Reaper, an upgraded version of the Predator, to the Air Force. The Reaper can fly higher and faster than the Predator, and carries a variety of weapons.

2009 — A photographer in Kandahar, Afghanistan, captured an image of the stealth RQ-170 drone, which aviation watchers called the “Beast of Kandahar.” Its mission: slip past air defense radar into countries like Pakistan and Iran. US officials soon leaked that RQ-170 had been used to keep tabs on Osama bin Laden’s compound in Abbottabad in 2011. One RQ-170’s life was cut short, however, when it was captured by Iran later that year, possibly after Iran intercepted the signal used to control it. Last week, Iran claimed it had cloned the drone. It’s unclear how many RQ-170s exist.

The Future

After the retirement of the SR-71 Blackbird spy plane, the military had an obvious gap in its arsenal.

In 2007, satellite pictures emerged showing new construction at Area 51, the Pentagon’s top-secret testing area in the Nevada desert. Veteran watchers of “black,” or secret, aircraft, immediately suspected that the Pentagon was preparing to test a new secret aircraft, and the most likely candidate was a stealth drone.

Now, two unmanned spy drones are under development. One that appears almost ready for combat is the RQ-180, a stealthy spy drone built by Northrop Grumman. Though the Pentagon refuses to confirm its existence, Aviation Week & Space Technology ran this artist’s concept earlier this year and revealed a little about its rumored design.

The RQ-180 is designed to fly very high, for a very long time (perhaps as long as 24 hours). According to Aviation Week, it has a 130-foot wing span and a “cranked kite” stealthy design that would allow it to slip past enemy radar. Chances are it will only be used for surveillance, not attack, though it could carry out an electronic attack.

Another, recently revealed project is a high-altitude drone being developed by Lockheed Martin that can travel up to six times of the speed of sound. The drone would be both a spy and strike aircraft, according to Lockheed. But the SR-72, as Lockheed is calling the twin-engine aircraft, wouldn’t be ready to fly until 2030.

What about a replacement for a Predator? The original Predator was essentially a surveillance aircraft that was turned into an armed drone, so any future replacement aircraft would likely look very different. The Pentagon has openly funded work on unmanned combat aircraft, including Northrop Grumman’s X-47, a diamond-shaped drone that can take off and land from aircraft carriers. But aerospace watchers have long presumed that these programs are hiding even more secretive work.

Part of the difficulty of deciphering the world of drones is that the Pentagon for over three decades has run a series of overlapping projects, often using unclassified programs as “covers” for more secret unmanned aircraft work.

Aviation Week, for example, says the RQ-180 was part of a secret, three-way contest that involved competing drones from Lockheed and Boeing. What happened to those other unmanned aircraft is unclear. Figuring out which are “real” drone project meant for deployment, and which are covers for secret drones, is a shell game.

Small & ubiquitous

Even the stealthy killer drones known or suspected to be under development fall short of some of the unmanned aircraft depicted in science fiction or thriller novels, which often feature swarms of autonomous killing machines. It is true that the Pentagon has been funding work to make drones operate with greater autonomy — for example, one of DARPA’s latest proposals calls on researchers to design ways to have drones collaborate with each other, such as having drones share information about a target.

But drones that can operate completely without the need for a pilot sitting in an air-conditioned trailer on a base in Nevada are still several years away, at least, and the Pentagon has long insisted that drones won’t be allowed to use weapons without a “man in the loop.”

Yet another longtime goal of military work is to create tiny drones, possibly disguised as birds or even insects (the CIA did develop a robotic dragonfly, though it never proved useful).

In terror expert Richard Clarke’s new novel, “Sting of the Drone,” the CIA operates stealthy mini-drones that are capable of assassinating someone inside a bar, and there is certainly evidence such drones are of interest. A four-minute animated video created by the Air Force Research Laboratory showed up on the Web in 2009, illustrating the lab’s work on micro aerial vehicles. The video featured a kamikaze insect-sized drone loaded with high explosives.

But drones of that level of sophistication — able to perch on telephone wires or hunt down terrorists inside a building — still belong to the future.

The real drone revolution may come not through sophistication of drones, but the proliferation of drones. So far, unmanned aircraft have largely been the weapons of technologically advanced nations, but that is changing as drone technology becomes cheaper and more accessible.

Just as improvised explosive devices, or IEDs, fast became the No. 1 killer of US troops in Iraq and Afghanistan, experts are now warning that crude drones — in some cases essentially sophisticated model airplanes — could be the real threat in the years to come.

Indeed, Hezbollah has already bragged of sending spy drones into Israeli territory, and Israeli leaders have warned of the possible drone threat that Hamas could pose from Gaza.

And a recent report by the Rand Corporation warned that, in the future, terrorist groups might be able to buy small, armed drones: “Smaller systems could become the next IEDs: low-cost, low-tech weapons that are only of limited lethality individually but attrite significant numbers of US or allied personnel when used in large numbers over time.”

The US military holds an annual exercise called Black Dart, which looks at ways to counter hostile drones, particularly small drones. Among the possible defenses are lasers to shoot down drones or systems that can jam the radio signals used to control drones. But this sort of counter-drone technology is scarce today.