The latest prototype in the Pentagon’s attempts to develop what is, in essence, a Mach 20 drone that can strike any target on earth within an hour, lasted no more than about 30 minutes before losing contact with ground stations Thursday.
Assuming the technology for hypersonic flight can be perfected, "and that's a big if, this plan is less bad than some of the other ones rolled out," says Noah Shachtman, a fellow with the Brooking Institution in Washington who focuses on security issues and 21st-weapons systems.
It certainly beats another idea the Pentagon proffered – putting conventional warheads on submarine-launched Trident missiles. Because these missiles are currently nuclear-tipped, launching one – with any warhead – on the familiar up-and-down trajectory would very likely invite a nuclear response.
The design the agency green lighted for further development actually will look and fly much like a hummingbird. The winning concept, developed by AeroVironment, is called Nano Scout (Nano Sensor Covert Observer in Urban Terrain). It is a remote-controlled, battery powered NAV with two flapping wings that weighs about two grams (about as heavy as two nickels) and is just slightly longer than three inches.
Lots of competition
The Scout is designed to fly forward at speeds of up to 20 mph, slow down to one mph for precision navigation inside buildings, withstand five mph wind gusts, operate inside buildings and have a range of over one-half mile.
The Nano Scout was selected over competing concepts submitted by Lockheed Martin,MicroPropulsion Inc., and Draper Laboratory at the end of the program’s first phase last year.
An early prototype tested by the company has already reached a technical milestone by achieving a hovering flight equal to that of a two-wing flapping wing aircraft while carrying its own energy source and using only the flapping wings for propulsion. A working prototype, scheduled for demonstration to DARPA when the second phase of the NAV program ends this summer, will have a flight endurance of 11 to 20 minutes.
But DARPA and AeroVironment aren’t the only players with a wing in the NAV game. Though its monocoptor design that is shaped like a maple leaf was passed over for the second phase of the DARPA program, Lockheed Martin Skunk Works’ Advanced Development Programs is continuing its exploration of NAVs on its own dime with the Samurai program.
The company has built two larger mono-wing vehicles as part of the program, a 30-inch flyer and a 12-inch version that is small enough to fit into a backpack and fly through an open window to enter a building. The Samurai design, says Kingsley Fregene, principal investigator for the program, is inherently stable and has few moving parts, which makes it a robust, aerodynamically clean airframe. Unlike more conventional designs, the entire aircraft rotates.
"A lot of structures in insects are multifunctional," he said. "Biologically, they’re multitasking."
The research is still in its early stages. "A lot of seminal research needs to be done," Adams said, adding that the missionization of NAVs, though, is not that far away.
"Within 10 to 15 years, autonomous microsystems will be on the battlefield."