Robotic hummingbirds. Real-life "Terminators." Tiny, disposable satellites.

Sometimes, there seems to be no end to the imaginations of the folks at DARPA -- the U.S. Defense Advanced Research Projects Agency -- or to the projects they're prepared to spend taxpayer money on. But one thing you can't deny about DARPA: The ideas are unfailingly cool.

Meet the Atlas, designed by Boston Dynamics, funded by DARPA. Source: Boston Dynamics.

Take DARPA's latest project, for example. Last week, the U.S. Department of Defense announced that DARPA had awarded a pair of contracts to two of the nation's bigger defense contractors, Northrop Grumman (NOC -0.38%) and Lockheed Martin (LMT -0.23%). Valued at $14.6 million and $11.4 million, respectively, both defense contracts fund research and development under DARPA's "Endurance" program, which aims to develop an airborne laser.

According to unclassified portions of DARPA's fiscal year 2014 budget request, work on Endurance has already begun in 2013, but the bulk of the funds allotted last week will be spent next year. If all goes well, Northrop and Lockheed will then continue working on this project until an actual working system results -- sometime in December 2016.

What might an airborne laser look like? Here's one artist's rendering. Source: Wikimedia Commons.

What Endurance is
Endurance is a classified government defense program, designed to produce a "pod-mounted" laser system that aircraft can carry to protect them from heat-seeking guided surface-to-air missiles.

What kind of aircraft? DARPA says the technology, which requires "miniaturizing component technologies, developing high-precision target tracking, identification, and lightweight agile beam control to support target engagement," could apply to "a variety of airborne platforms." The tech derives from an earlier DARPA program, "Excalibur," whose stated aim was to protect "next-generation airborne platforms, including all aircraft flying at altitudes below 50,000 [feet] ... against proliferated, deployed, and next-generation man-portable air-defense systems (MANPADS)."

Most commentators on the program, however, believe that what DARPA's really interested in is defending slow-flying unmanned aerial vehicles, or UAVs, against heat-seeking missiles. And indeed, the kind of miniature lasers being discussed here will be essential if drones are to be able to carry onboard laser-based antimissile defenses. Current technology is, after all, rather bulky. For context, this is how big the laser wound up being, when the Pentagon hired Boeing (BA -0.31%) to help build an airborne laser:

The shootin' end of Boeing's Air-Borne Laser project. Source: Boeing.

Wanted: Defense contractor to build an X-Wing Fighter
Ultimately, though, DARPA's goal may be more ambitious. According to DARPA's own documents, the initial plan for the Excalibur program was to "develop coherent optical phased array technologies to enable scalable laser weapons that are 10 times lighter and more compact than existing high-power chemical laser systems." But farther down the road, the agency hoped to scale up this laser system several times in strength, developing 100-kilowatt (and up) lasers capable of conducting "precision strikes against both ground and air targets."

Luckily for DARPA, both Lockheed and Northrop have experience in this realm, having worked (alongside Raytheon (RTN), which was responsible for the tracking system) on the Boeing-led team that built the Air-Borne Laser back in 2004. While that program has since been canceled, this new round of DARPA funding suggests that we might get a Defense Department-built X-Wing fighter yet.

The secret Pentagon X-Wing Fighter Project ... farther along than we think? Source: Wikimedia Commons.