Stalker EX Mini-UAV Set for Eight Hour Endurance Missions

An extended Endurance 'Marine stalker' is optimized for Marine Corps use. Photo: Tamir Eshel, Defense Update

Lockheed Martin has developed a ruggedized, fuel-cell powered version of its Stalker Unmanned Air System (UAS), called the Stalker eXtreme Endurance (XE) UAS. The new version quadruples the original Stalker’s flight endurance to eight-plus hours, without impacting the mobility of the unmanned system or the flexibility of its payload capabilities.

The Stalker, on display at Lockheed Martin booth at the AUVSI 2011 show. Photo: Tamir Eshel, Defense-Update

The complete Stalker XE system includes two aircraft, fuel cells, command and control ground station, support equipment, and small propane fuel storage tank. The standard air vehicle sensor is a modular dual daylight and night-time imager that allows persistent surveillance during the visual/thermal transition from day to night.

Marinized Stalker, a version offering extended range and endurance to support Marine Corps applications. Photo: Tamir Eshel, Defense-Update

The Stalker XE system is powered by Ultra Electronics’ pioneering hybrid energy source using a propane fuel cell with a small, conventional lithium polymer battery to handle power peaks. This long-endurance fuel cell technology was developed through an innovative Defense Advanced Research Projects Agency (DARPA) sponsored effort led by Lockheed Martin and Adaptive Materials Incorporated (now a division of Ultra Electronics Holdings, plc). The DARPA project culminated with a rigorous flight test program including numerous back-to-back, long endurance intelligence, surveillance and reconnaissance high altitude and high wind flights proving that the Stalker UAS met or exceeded all technical and performance milestones.

“Missions requiring real time eyes-on a situation for extended periods of time, like border patrol, pipeline surveillance and special operations can now be conducted by a small UAS versus a larger, more costly system,” explained Tom Koonce, Lockheed Martin’s Stalker program manager. ‘The convenience and lower cost of a small UAS combined with extended endurance is a true game-changer.”


    • Elbit has not yet made this flight, the article tells they are preparing the fuel cell aplication for it. By the way, the same fuel cell (Protonex) already flew with another UAV, the Ion Tiger, that have set the world record for fuel-cell powered UAV endurance of just over 26 hours. This technology also powers other Navy UAVs designed for launching from submarines (XFC). Yet, another company, the Canadian-based Energy Orr, has recently demonstrated over 10 hours of flight with the Faucon ‘flying wing’ UAV, powered by their own PEM fuel cell. We plan to publish an article covering these new fuel cells soon.

  1. No, this is not a prototype. It is a fully functional, combat ready airframe. It has been tested with functional payload, avionics, and environmental concerns all were tested. As far as the Protonex stuff, not exactly true. As I work for Ultra, I dont want to bash another manufacturer, but they know the truth, and their “claim” is not real. Oh, and lets look at fuel. Stalker XE is run off propane/LPG. What about the Protonex? Ah ha….not so easy to fuel that bad boy is it? Enough said…

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