CAMP BASTION, Afghanistan — In January a small group of U.S. Marines at a remote base near the village of Shurakay in northern Helmand province was running low on ammunition after fighting fiercely for days. The road in was too dangerous for a resupply convoy, and there were so many Taliban fighters that a helicopter crew trying to fly in would have been at serious risk.Still, the Marines soon heard the soft thwack of rotor blades. They looked up as a glimpse of the future of aviation eased into a hover, then gently descended until a pallet of ammunition dangling beneath it touched ground. The cargo hook released itself and the unmanned K-MAX helicopter rose again, turned and flew off.The K-MAX, which is the only drone cargo helicopter in the U.S. military fleet, made two more runs to the embattled outpost, dropping off more supplies each time.It wasnt a stunt: In 16 months, two K-MAX helicopters that were sent to Afghanistan as an experiment have delivered 3.2 millions of pounds of cargo across Helmand and flown more than 1,000 missions. Thats reduced the number of supply convoys needed on the provinces bomb-infested roads, eased the workload and risk for helicopter and Osprey crews, saved money and provided real-world proof that drones are practical for much more than surveillance and missile strikes.The combat-zone test was supposed to last six months, but in March the Marine Corps extended it indefinitely, citing the K-MAXs success in delivering cargo and keeping Marines in trucks off dangerous roads.In the fast-growing world of unmanned aircraft, the K-MAXs success is a significant step toward whats expected to be a host of new military and civilian roles for cargo drones, said Peter Singer, director of the 21st Century Defense Initiative at the Brookings Institution research center and the author of Wired for War: The Robotics Revolution and Conflict in the 21st Century.Everyone has framed discussion of drones as being about surveillance, and thats one of the models, but they wont be only that, he said.Indeed, surveillance seems likely to become no more than a niche for drones. Last year, Congress ordered the Federal Aviation Administration to open the airways to the commercial use of drones by 2015. The FAA foresees that 10,000 commercial drones will be flying by 2020. Predicted uses include carrying cargo, lifting construction materials into place, undertaking rescue missions in remote mountains or stormy seas, evacuating the wounded from battlefields and even, some experts half-joke, delivering pizza.Analyst estimates of the commercial market for unmanned aircraft range as high as $94 billion in the next few years.The national airspace will be opened, and now thats not an if its when, Singer said. The importance of the K-MAX is that it provides proof of concept that there is a potential commercial use, not just a military one. Its the best current example of cargo movement by an unmanned aircraft. Its working a lot, working well and doing so in a pretty tough environment.The implications, he said, may be extrapolated by looking at the history of manned aviation. That started with wartime surveillance, then moved onto carrying improvised, then standard, armaments in World War I. After the war, airplanes expanded into moving freight and passengers. The K-MAX and similar competitors are the first shift for drones away from surveillance and air-delivered weapons into freight and the rest of the future for drones, he said.The Marines also think its breaking ground for new drone uses, inside and outside the military.It might take some time in the United States for a civilian application, but the crews here are proving it works and that its incredibly reliable and cost-effective, said Maj. Daniel Lindblom of Alexandria, Va., who oversees the unmanned aircraft programs the Marines run in Afghanistan. Its just a matter of time.The K-MAX looks a little odd, with its side-by-side rotors, narrow fuselage and no tail rotor, but it isnt startlingly futuristic. Thats because it is based on a manned civilian cargo helicopter that had proved itself for years as Lockheed Martin searched for a simple way to meet the requirements of the test without a vast investment in research and development to build a drone from scratch. It joined forces with the original builder of the K-MAX to convert the helicopter to work by remote operation and automation.It still has a cockpit, and a pilot can taxi it into place before the cargo is attached or fly it around for maintenance checks. When its time to lift the cargo, the pilot flicks a switch to NOLO no local operator steps out of the cockpit and walks away.The Sony factorIn a converted shipping container nearby, an operator at the helm of a Sony PlayStation video-game console takes over and a crew hooks on the cargo, which dangles on a sling about 75 feet below the K-MAX as it flies off.The PlayStation is simple, cheap, reliable and already familiar to many people, members of the K-MAX ground crew said. If a controller gums up or breaks, someone drives over to the Marine PX and buys another, said Phil Melton, a pilot from Priest River, Idaho, who works for Oregons Swanson Group Aviation. Swanson has the contract to maintain and operate the K-MAX at Camp Bastion.After takeoff, much of the helicopters flight is automated. K-MAX uses GPS satellite navigation to follow a preset path thats filed with air traffic controllers. There isnt a video camera aboard, which is one reason its important that its routes be carefully coordinated in advance with air traffic controllers and others, such as combat air controllers on the ground. It also means the ground crew cant see approaching thunderstorms, so theyre careful to fly only when theres little chance of a surprise in the weather.It can travel about 80 miles each way, but its best at distances of 58 miles or less because then it can be controlled by a line-of-sight radio system. If it goes farther, the crew has to switch to a less reliable satellite telephone to control it.Once it reaches its destination, the ground crew at Camp Bastion is in communication with the troops at the other end, who tell them when the helicopter is in position to ease the cargo down safely. The operator at the PlayStation console hits a deliver button and the K-MAX descends automatically at a controlled rate to about 90 feet, then slows the descent to a crawl.When the cargo settles to the ground, a weight sensor triggers the release of the cargo hook, and the K-MAX automatically climbs into the sky again and follows the preset path back to the air base at Camp Bastion, the British side of the huge joint base that includes the main Marine base in Afghanistan, Camp Leatherneck.All the automation at the delivery end is necessary because the helicopter can dip below the horizon when it descends, meaning that the line-of-sight control system no longer works. But it will still automatically set down its cargo and rise back to the point where its controllable again.Little-known programThe program isnt secret, but its almost unknown on base. The helicopters fly from a remote corner of Bastion, mainly at night, when the weathers usually better and the air cooler and denser, so the rotor blades are more efficient.The aircraft now fly as many as six flights a day, six days a week. Often they fly cargoes of water or food, but they also have delivered crucial replacement parts for the improvised bomb-defeating system on a damaged truck and fuel to a small base that was running out.In Helmand, theyve built an enviable record of reliability and cost-effectiveness, Lindblom said. The aircraft need only about 1.3 staff-hours of maintenance for every hour of flight, and they cost little more than $1,300 an hour to operate, he said. That compares with nearly 23 staff-hours for each hour of flight for the CH-53E heavy-lift helicopter and more than $11,000 an hour to operate it, according to the Marine Corps.The cost savings, performance and reduction in the risk and drudgery mean that the wider use of such helicopters, inside and outside the military, is inevitable, Lindblom said.This is the wave of the future, and theres just no question about it, he said. About the only problem with it is that we dont have 20 or 30 more of them.