• Protect Local Air Quality and Our Global Climate- Reduce NOx emissions of future aircraft by 70% by 2007 and by 80% by 2022 (Baseline: 1996 ICAO Standard). Reduce CO2 emissions of future aircraft by 25% by 2007 and by 50% by 2022.

The efforts within Zero CO2 Research Project which are directed at reducing the permeability to hydrogen of composite fuel tanks also supports Goal Two of the OAT Goals: Advanced Space Transportation; and Objective Seven within Goal Two:

• Reduce the Cost of Taking Payloads to Orbit - Reduce the cost of delivering a payload to Low Earth Orbit (LEO) by a factor of ten by 2010 and reduce the cost of inter-orbital transfer by a factor of ten by 2015. Reduce costs for both by an additional factor of ten by 2025.

The systems analysis efforts that conceptualize revolutionary zero CO2 propulsion systems will support Goal Three of the OAT Goals: Pioneer Technology Innovation; and Objective 9 within Goal Three:

• Engineering Innovation - Develop the advanced engineering tools, processes and culture to enable rapid, high-confidence and cost efficient design of revolutionary aerospace systems.

The Zero CO2 Research Project is focused on radically reducing the emissions signature of subsonic propulsion systems. Currently all subsonic commercial aircraft utilize hydrocarbon fuels as their energy source. These fuels result in the emission of copious amounts of CO2 and water vapor, and to a lesser degree oxides of nitrogen and unburned hydrocarbons. All of these emissions, with the possible exception of water vapor, are emerging as threats to the long-term health of the planet.

Emerging fracture toughened fuel cell electrolyte materials coupled with advanced operation of Proton Exchange Membrane and/or Solid Oxide Fuel Cells in a high pressure air cycle may significantly enhance fuel cell performance as measured in watts per pound. Reduction of the hydrogen permeability of lightweight Polymer Matrix Composite fuel tanks may allow the efficient storage of low density liquid hydrogen in subsonic aircraft. These advances may enable the revolutionary application of electric propulsion to subsonic aircraft with the benefit of zero CO2 and NOx emissions.

The ability to reduce CO2 emissions to zero and NOx emissions by a factor of five over current hydrocarbon burning gas turbine engine technology will be verified by burning hydrogen in a flame tube combustor at simulated gas turbine engine operating conditions. While hydrogen appears to be a near perfect fuel with respect to emission signature, it has the potential to generate copious amounts of "prompt" NOx in advanced high pressure, high temperature gas turbine cycles. The ability to develop fuel injection technology that controls this "prompt" NOx production is a necessity for the successful use of this fuel. The development of these technologies when coupled with efficient low permeability, light weight Polymer Matrix Composite liquid hydrogen tanks may allow the introduction of hydrogen fueled gas turbine subsonic aircraft in the future.

In addition, a thorough systems analysis of exotic fuel cell electric hybrid and advanced open cycle gas turbine systems optimized to fully exploit the beneficial physical properties of liquid hydrogen will be conducted. These analyses will determine the feasibility of far term application of liquid hydrogen as a fuel for both hybrid fuel cell aircraft propulsion and optimized subsonic gas turbine propulsion systems. This analysis will also determine technology short falls at the end of three years that may inhibit the application of hydrogen as a subsonic aircraft fuel.