The technology of the future is already upon us. Not much stands in the way of drones that can fly in any environment and loiter for hours, autonomously searching—looking, but also waiting to pounce.

One such example is the fuel cell-powered XFC or eXperimantal Fuel Cell, an unmanned system developed by the Naval Research Laboratory (NRL) during the late 1990’s.

The eXperimental Fuel Cell is fully autonomous and expendable. The hydrogen fuel cell provides power for propulsion, avionics, command and operation of the payload, whether it is the current sensor or a future weapon. On June 2, 2009, the NRL completed a successful launch from a transport tube. cell powered XFC (eXperimental Fuel Cell) unmanned aerial system (UAS). During the June 2 flight test, the XFC successfully ejected from the tube, unfolding to its X-shaped configuration and flying over five hours, delivering imagery back to the ground. The laboratory called it “long endurance” and foresaw the XFC being modified for launch from a submarine, scouting for ships or other drones, even eventually attacking those threats.

The next step was launching the XFC from a torpedo tube on a submerged submarine (the USS Providence) while at sea. The carrying tube floated to the surface and stabilized and then the XFC drone was ejected. On that flight, it soared for over four hours, streaming back live video.

And then it disappeared: Not the XFC itself, but the program. Since 2012, the NRL hasn’t said another word about XFC nor what happened to the program. But here it is, a semi-autonomous and long-distance weapon with all of the potential of any Hellfire missile on a Predator or Reaper, launchable from a lurking submarine to find and attack pirates, to be part of a special operations mission, to be the vanguard of an amphibious assault. Virtually undetectable, just as it is invisible within the vast defense budget and machinery of drones, XFC will (or is it already) add another arrow to the quiver, a secret and stealth warrior.