Martin had flown his machine thousands of times before the May launch, but never higher than a few feet. Since the jetpack's first public flight in 2008, Martin and his team of 10 engineers haven't changed its basic design: a two-stroke, custom-designed gas engine spins a pair of ducted fans that generate thrust. They did, however, convert the original cable-and-pulley steering system to an entirely electronic, fly-by-wire system. A cellphone-size flight-control unit made by defense contractor Rockwell Collins and commonly used in Predator UAVs allows Martin to set bounds on pitch, roll and yaw, and generally steadies flight, canceling out a new pilot's jerky maneuvers (it also means no backflips, unfortunately). By adding remote control to the jetpack, its applications expand. A search-and-rescue team, for example, could remotely pilot a Martin Jetpack to a hard-to-reach spot in a disaster zone, instruct a victim to strap in, and fly him to safety. Or soldiers could use the jetpack to fly a mini cellphone tower to a hilltop for temporary communications.