Balcones Technologies (BT), LLC proposes to leverage technologies developed by and resident in BT, The University of Texas Center for Electromechanics (CEM) and Applied Nanotech Incorporated (ANI) in the areas of carbon nanotube composites (CNT) and terrestrial and space-based flywheel energy storage systems to address SBIR 2012 subtopic S3.04 Power Electronics and Management, and Energy Storage. To provide a near term commercial focus in addition to NASA space applications, BT is augmenting this team with Astral Infinity (AI) to provide one target application that requires flywheel energy storage systems with characteristics that exceed current flywheel systems and exceed lithium battery capabilities a solar powered high altitude long endurance unmanned air vehicle. This proposal, focuses on making a major near-term advancement in flywheel energy density, with high potential for further longer term advancements, by exploiting ANI carbon nanotube expertise and CEM/BT flywheel technology. After having plateaued for two decades, there is a good probability of attaining near-term improvement of 30%-50% for flywheel rotor specific energy by reinforcing the carbon fiber composite matrix material with CNT. Subsequently, there is a potential improvement in the medium to longer term of an order of magnitude or more by also replacing the current carbon fibers with fibers composed of CNTs. Our program focuses on the near-term objective and is a first and appropriate step in the longer term objective. In particular, for this Phase I project our team will: 1.Develop a concept design for a flywheel rotor that relies on CNT reinforced composite flywheels for a 30%-50% increase in flywheel stored energy per kg to substantially exceed the specific energy performance of chemical batteries (e.g., lithium batteries) for most space-based and terrestrial applications of a few kW-hrs or more, and 2.Complete an initial round of CNT materials testing to support the design.