A report discusses a 7-meter-diameter reflectarray antenna that has been conceived in a continuing effort to develop large reflectarray antennas to be deployed in outer space. Major underlying concepts were reported in three prior NASA Tech Briefs articles: "Inflatable Reflectarray Antennas" (NPO-20433), Vol. 23, No. 10 (October 1999), page 50; "Tape-Spring Reinforcements for Inflatable Structural Tubes" (NPO- 20615), Vol. 24, No. 7 (July 2000), page 58; and "Self-Inflatable/Self-Rigidizable Reflectarray Antenna" (NPO-30662), Vol. 28, No. 1 (January 2004), page 61. Like previous antennas in the series, the antenna now proposed would include a reflectarray membrane stretched flat on a frame of multiple inflatable booms. The membrane and booms would be rolled up and folded for compact stowage during transport. Deployment in outer space would be effected by inflating the booms to unroll and then to unfold the membrane, thereby stretching the membrane out flat to its full size. The membrane would achieve the flatness for a Ka-band application. The report gives considerable emphasis to designing the booms to rigidify themselves upon deployment: for this purpose, the booms could be made as spring-tape-reinforced aluminum laminate tubes like those described in two of the cited prior articles.
This work was done by Houfei Fang, John Huang, and Michael Lou of Caltech for NASA's Jet Propulsion Laboratory. For further information, access the Technical Support Package (TSP) free on-line at www.techbriefs.com/tsp under the Mechanics category. NPO-41083
This Brief includes a Technical Support Package (TSP).
Large Deployable Reflectarray Antenna
(reference NPO-41083) is currently available for download from the TSP library.
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Overview
The document presents the development of a 7-meter inflatable/self-rigidizable reflectarray antenna intended for space communication applications. This innovative antenna architecture utilizes beam scanning and circular polarization technology, allowing for a flat surface design instead of a traditional parabolic shape. The flat surface is easier to fabricate, package, and maintain, making it suitable for various space missions.
The project builds on previous experiences with smaller reflectarray antennas, including a one-meter X-band model and a three-meter Ka-band model. The three-meter antenna, shaped like a horseshoe, demonstrated excellent radiation pattern characteristics during RF testing. Its design facilitates compact packaging, as the inflatable structure can be deflated and rolled onto a rigid tube assembly without significant wrinkling of the membrane.
A key feature of the 7-meter antenna is its deployment mechanism, which employs a “movie screen” scheme. This involves two inflatable booms that deploy the reflectarray surface similarly to how a movie screen unfolds. The booms utilize a JPL-developed technology known as the Spring Tape Reinforced Aluminum Laminate Boom. This self-rigidizable boom automatically becomes rigid after inflation, requiring no additional space power or curing agents to maintain its structure. This technology enhances the antenna's reliability and simplifies its deployment process.
The document also addresses the challenges associated with scaling up to a larger aperture, which is over five times the size of the previous model. The larger size necessitates folding for stowage within conventional launch vehicle fairings, making the deployment process more complex. The deployment sequence involves the feed moving out of the way, followed by the unrolling of the membrane and inflation of the booms, culminating in the full deployment of the antenna.
Overall, the development of the 7-meter inflatable reflectarray antenna represents a significant advancement in space communication technology. Its innovative design and deployment mechanisms promise to enhance the capabilities of future space missions, making it a valuable asset for NASA and other space exploration endeavors. The document serves as a technical support package, providing insights into the engineering and technological advancements that underpin this cutting-edge antenna system.
