A new modular solar powered rocket engine is proposed to provide a few milligrams to a few kilograms of thrust at 900-1000 seconds of specific impulse by heating hydrogen propellant to average temperatures ranging from 2750 to 3250K. The proposed design utilizes one or several sunflower-like clusters of nonimaging concentrators coupled to optical fiber bundles that guide the solar energy with a throughput of greater than 80% into a Plank cavity/thrust chamber. The Plank cavity receives and entraps solar energy for direct heating of hydrogen and/or storage in a composite thermal storage unit. A nested flow path is designed to force hydrogen flow along the thermal storage/cavity temperature gradient, thereby, producing variable levels of thrust at relatively constant specific impulse of 900 to 1000 seconds. The innovative use of the sun tracking concentrators coupled to optical fibers, combined with the composite thermal storage unit/Plank cavity will allow for receiving and utilization of more than 80% of solar energy for producing thrust. This is a revolutionary improvement over existing solar-electric powered space propulsion systems and could lead to the development of an ultralight, compact, and an order of magnitude lower cost propulsion system for space transportation and solar system exploration. POTENTIAL COMMERCIAL APPLICATION(S) : NeTech is planning to develop the following technologies that are expected to be of a wide range of applications to space power and propulsion industry: 1) The most significant application of the proposed work is the development of a low cost, ultra-compact, and lightweight solar thermal propulsion system for a wide range of space transportation applications. 2) Development and marketing of glassy carbon container for containment of high temperature corrosive materials. 3) Fabrication technology for low porosity forms of carbon. 4) Refractory carbide coating techniques for graphite and other forms of carbon. The EB-PVD and PVD-thermocarburizing techniques provide for gradient coating of graphite with stoichiometric and non-stoichiometric carbides. NeTech will pursue commercial applications of the modular solar thermal propulsion system as well as the glassy carbon and refractory carbide coating technology both as industrial products and also as service to the industry. NeTech will also pursue the marketing of its computational fluid dynamic and heat transfer capabilities to the aerospace power and propulsion industry.
