Technology Assessment and Development of Large Deployable Antennas

A National Aeronautics and Space Administration (NASA) research and technology program called the large deployable antenna (LDA) program was initiated in early 1989 by NASA Langley Research Center to investigate and demonstrate the availability of critical technologies for passive microwave imagers. The NASA Office of Aeronautics, Exploration, and Technology (OAET) sponsored this research program to provide advanced sensor technologies for mission to planet Earth remote sensing applications. The goal of the OAET program is to provide the technology needed to enable and enhance the long‐term observations, documentation, and understanding of the Earth as a system. The LDA program involved university, industry, and NASA researchers and technologists with a range of skills and experience from electromagnetic theory to advanced materials and deployable structures. The study approach involved determining basic operational parameters and configurations for a geosynchronous wide‐scanning radiometer from which specific structural requirements were used as goals (rather than specifications) with which specific technologies could be evaluated. The study team performed a detailed technology review, evaluated the feasibility and technology readiness for a large dual‐reflector radiometer, and developed a system concept for a 25 m deployable radiometer. This paper describes the science objectives, reviews the current state of the art, presents electromagnetic configurations under consideration, and discusses the mechanical systems development effort.