Joe T. Howell

Stretched Lens Array (SLA) for Collection and Conversion of Infrared Laser Light: 45% Efficiency Demonstrated for Near-Term 800 W/kg Space Power System

For the past 2frac12 years, our team has been developing a unique photovoltaic concentrator array for collection and conversion of infrared laser light. This laser-receiving array has evolved from the solar-receiving Stretched Lens Array (SLA). The laser-receiving version of SLA is being developed for space power applications when or where sunlight is not available (e.g., the eternally dark lunar polar craters). The laser-receiving SLA can efficiently collect and convert beamed laser power from orbiting spacecraft or other sources (e.g., solar-powered lasers on the permanently illuminated ridges of lunar polar craters). A dual-use version of SLA can produce power from sunlight during sunlit portions of the mission, and from beamed laser light during dark portions of the mission. SLA minimizes the cost and mass of photovoltaic cells by using gossamer-like Fresnel lenses to capture and focus incoming light (solar or laser) by a factor of 8.5X, thereby providing a cost-effective, ultra-light space power system

Modular, Reconfigurable, High-Energy Technology Development

The modular, reconfigurable high-energy (MRHE) technology demonstrator project was to have been a series of ground-based demonstrations to mature critical technologies needed for in-space assembly of a high-power high-voltage modular spacecraft in low Earth orbit, enabling the development of future modular solar-powered exploration cargo-transport vehicles and infrastructure. MRHE was a project in the high energy space systems (HESS) program, within NASAs Exploration Systems Research and Technology (ESR&T) Program. NASA participants included Marshall Space Flight Center (MSFC), the Jet Propulsion Laboratory (JPL), and Glenn Research Center (GRC). Contractor participants were the Boeing Phantom Works in Huntsville, AL, Lockheed Martin Advanced Technology Center in Palo Alto, CA, ENTECH, Inc. in Keller, TX, and the University of AL Huntsville (UAH). This paper presents an overview of the MRHE Phase I activities at MSFC and its contractor partners. The assembly demonstration in the Lockheed Martin Advanced Technology Center (LMATC) Robot-Satellite facility was a major Phase I accomplishment. Three robot-satellites successfully demonstrated rendezvous & docking, self-assembly, reconfiguration, adaptable GN&C, deployment, and interfaces between modules. ENTECHs Phase I technology maturation accomplishments include material recommendations for radiation-hardened Stretched Lens Array (SLA) concentrator lenses, and a design concept and test results for a hi-voltage PV receiver. UAHs accomplishments include Supertube heat-pipe test results, which support estimates of thermal conductivities at 30,000 times that of an equivalent silver rod. MSFC performed systems trades and developed a preliminary concept design for a lOOkW-class modular reconfigurable solar electric propulsion transport vehicle. Boeing Phantom Works in Huntsville performed assembly and rendezvous and docking trades and launch vehicles and orbit analysis. A concept animation video was produced by SAIC, which showed rendezvous and docking and SLA-square-rigger (SLASR) deployment in LEO.