A report describes recent progress in a continuing effort to develop large reflectarray antennas to be deployed in space. Major underlying concepts were reported in two prior NASA Tech Briefs articles: "Inflatable Reflectarray Antennas" (NPO-20433), Vol. 23, No. 10 (October 1999), page 50 and "Tape-Spring Reinforcements for Inflatable Structural Tubes" (NPO-20615), Vol. 24, No. 7 (July 2000), page 58. To recapitulate: An antenna as proposed would include a reflectarray membrane stretched flat on a frame of multiple tubular booms that would be deployed by inflation. The instant report discusses design concepts and relevant basic mechanical principles. Among the concepts are alternative configurations of booms for holding the reflectarray membrane and its radio-frequency feed horn and the use of catenaries and constant-force springs to stretch the reflectarray membrane on the frame at the required tension. Some emphasis is placed on the need to keep the deployed frame rigid without depending on maintenance of inflation in the presence of impinging micrometeors that could cause leaks: for this purpose, the booms could be made as spring-tape-reinforced aluminum laminate tubes like those described in the second-mentioned prior article.
This work was done by Houfei Fang, Michael Lou, and John Huang of Caltech for NASA's Jet Propulsion Laboratory.
NPO-30662
This Brief includes a Technical Support Package (TSP).
Self-Inflatable/Self-Rigidizable Reflectarray Antenna
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Overview
The document is a technical support package from NASA's Jet Propulsion Laboratory (JPL) detailing the development of an inflatable/self-rigidizable reflectarray antenna. This technology aims to address the growing demand for larger apertures in space science missions while overcoming the limitations imposed by launch vehicle size and weight constraints.
The reflectarray antenna represents a significant innovation in antenna design, utilizing a flat surface instead of a traditional parabolic surface to concentrate radio frequency (RF) energy. This flat, thin-membrane surface is easier to manufacture and maintain over long-duration space missions compared to curved surfaces. The key advancement is the use of an innovative "Spring Tape Reinforced (STR)" aluminum laminate boom, which allows the antenna to be packaged into a compact volume for launch. Upon reaching space, the antenna can be inflated and will automatically achieve the necessary rigidity without requiring prolonged pressure, facilitating a straightforward deployment process.
The document outlines the motivation behind this development, emphasizing the need for larger antennas to meet the scientific requirements of modern missions. It highlights the dual benefits of reducing both the weight and volume of the antenna, which can significantly lower launch costs and overall mission expenses. The inflatable technology enables the creation of a lightweight, large-aperture antenna that can be efficiently transported and deployed in space.
The technical disclosure section provides a detailed explanation of the antenna's components, including the inflatable tubular frame that supports and stretches the radiating aperture. The design allows the booms to be easily flattened and rolled up, enhancing the antenna's portability and ease of deployment.
The report also includes references to previous works and presentations related to the technology, showcasing the ongoing research and development efforts in this field. It emphasizes that the work was conducted under NASA's sponsorship and clarifies that any mention of specific commercial products does not imply endorsement by the U.S. Government or JPL.
In summary, this document presents a groundbreaking approach to antenna technology that promises to enhance the capabilities of space missions by enabling the deployment of large, lightweight antennas that are easy to launch and operate in the challenging environment of space.
