A robot helicopter that can carry three tons of cargo, the Marine Corps K-MAX certainly has the cool factor. But does it have a future?

After a six-month pilot project in Afghanistan got extended into a 33-month deployment that made 2,250 tons of deliveries, the two experimental aircraft have come home. Prime contractor Lockheed Martin is looking to the energy industry and — if export authorities approve — foreign military sales. Members of Congress have campaigned for K-MAX to become an official program of record for the US military, and Naval Air Systems Command (NAVAIR) is now working with the Marine Corps on formal requirements and new concepts of operations, with demonstration flights likely next year. Lockheed is even planning a demonstration later this year in which the unmanned helicopter will work with unmanned trucks. For now, though, the two robocopters will sit in storage while humans study the deployment.

The crucial question for K-MAX is the same one as for so many other innovative items of equipment rushed into service in the last 13 grueling years: Is it just a useful niche capability for a war that’s almost over or something relevant to a range of future missions?

Drones have a nasty tendency to crash even in good conditions, and the Marines’ area of operations in southwestern Afghanistan was a brutal natural environment for aircraft: high altitudes, thin air, temperatures as high as 138 degrees Fahrenheit, and “a very fine dust that is constantly blowing, seems like 24 hours a day, [and] gets in the equipment,” said Maj. Kyle O’Connor, who led the first deployment in 2011.

But militarily, the Taliban and their allies had little anti-aircraft firepower and no ability to hack or jam the wireless links between K-MAX and its human operators. In Afghanistan, K-MAX mostly flew at night — the GPS-guided robot didn’t actually need to see — and too high for Taliban small-arms fire. In the grim new world where Russian-backed irregulars can shoot down a civilian airliner at 33,000 feet with a radar-guided missile, altitude and darkness are no longer a sure defense.

In Afghanistan, “we did accept risk,” said Navy Captain Patrick Smith, NAVAIR’s program manager. They addressed the threat by how they flew the aircraft — i.e. high and dark — rather than by adding self-defense systems or more robust communications links to what was intended, after all as an affordable proof-of-concept. As the Navy and Marines work out their requirements for a future unmanned cargo chopper, he said, they’ll address “electronic attack, cyber, small arms, heavy arms,” the whole range of potential threats.

The idea of sending unmanned cargo aircraft to Afghanistan was to have fewer humans driving trucks up and down IED-infested roads. The question in future conflicts is whether the robots themselves survive long enough to do the job. The challenge is either to make K-MAX’s successor significantly tougher for an affordable price — or to make it cheap enough to be expendable.