NASA’s Office of Aerospace Technology (OAT) goals for aeronautics include protecting the local environmental quality and the global climate by reducing aircraft noise and emissions . In support of these objectives, the NASA Glenn Research Center has developed an Aeropropulsion Vision, which ultimately results in an emissionless, silent aeropropulsion system. This cleaner, quieter system is envisioned to rely on fuel cells and electromechanical syste ms for primary propulsion. These systems would use hydrogen fuel cells, which produce water vapor instead of CO 2 and NOx in the exhaust. NASA Glenn Research Center has begun investigating the possible technologies required for an emissionless, silent propulsion system at many levels including basic materials and reformer research for fuel cells, systems analysis, and detailed CFD and nodal analysis. Applications have been investigated for General Aviation, Commuters and small Commercial Airliners. This paper summarizes the investigations defining the technology requirements and examining the technology development challenges that NASA will address. Systems analysis has served as an initial investigation into various power and propulsion configurations and approaches. The results of these analyses are used as a basis for generating system and technology requirements. The electric drive propulsion technology requirements and challenges are discussed along with NASA’s current technology activities. Int roduction