Global Observer, Hydrogen powered UAV, Aims To Make Satellites Obsolete

http://www.msnbc.msn.com/id/39102502/ns/technology_and_science-tech_and_gadgets/

Unmanned platforms like the Global Observer that operate above 50,000 feet combine the capabilities of satellites with the flexibility of aircraft for persistent intelligence, surveillance and reconnaissance (ISR) missions. The aircraft is being developed by AeroVironment under a joint concept technology demonstration (JCTD) sponsored by several U.S. agencies under the direction of the Special Operations Command

The Global Observer has a 175-foot wingspan and weighs less than 10,000 pounds. It has a modular composite airframe, which enables it be transported by a cargo aircraft, and an internal-combustion engine modified to burn hydrogen that drives a generator to produce electricity to power the UAV’s four propellers. Hydrogen was chosen because it has three times the energy of conventional fuel. When in operation, the aircraft produces no carbon emissions.