A report proposes devices containing electrorheological fluids (ERFs) damper for controlling deployments of lightweight, flexible structures in outer space. The structures would include spring members that could be wound or compressed for compact stowage during transport. The ERF based damper would keep the structures compacted and/or regulate the speeds with which the structures would spring out for deployment. After deployment, ERF based dampening mechanism could be used to rigidize the structures or damp their vibrations. The report describes several potential variations on the basic concept of an ERF-controlled structural member, including compartmentalization of the interior volume to prevent total loss of the ERF in case of a leak and the use of multiple, individually addressable electrode pairs to enable more localized control.
This work was done by Yoseph Bar-Cohen, Zensheu Chang, Moktar Salama, Xiaoqi Bao, and Stewart Sherrit of Caltech; Christopher Jenkins of SDSM&T; and Aleksandra Vinogradov of Montana State University for NASA's Jet Propulsion Laboratory.
This Brief includes a Technical Support Package (TSP).
Using ERF Devices To Control Deployments of Space Structures
(reference NPO-30587) is currently available for download from the TSP library.
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Overview
The document is a technical support package prepared under the sponsorship of NASA, detailing the use of electro-rheological fluids (ERF) in controlling the deployment of ultra-lightweight compliant space structures, such as antennas. The report, identified as NASA Technical Brief Vol. 27, No. 2, was published on February 1, 2003, and is associated with JPL New Technology Report NPO-30587.
The primary focus of the document is on a novel active control mechanism that enhances the deployment rates and stability of lightweight space structures. These structures, often made from flexible membranes, are crucial for various space applications, including antennas, solar sails, and telescopes. The report identifies a significant problem in the current deployment methods, which predominantly rely on passive control strategies, such as the use of "carpenter tape" and Velcro. These methods have limitations, including lack of control once deployed and potential for uneven deployment.
The innovative ERF-based mechanism offers several advantages over traditional methods. It allows for active control of deployment rates, vibration damping, and shape control, which are essential for maintaining structural integrity during deployment. The mechanism can also create artificial struts, enhancing the rigidity of the structures when needed. The use of compartmentalized cells within the ERF system ensures durability, even if one cell is damaged, and allows for controlled distribution of mass and stiffness.
The document emphasizes the low power requirements and the well-researched electromechanical response of ERF, which can be manipulated through electrical fields to achieve desired performance characteristics. This active control mechanism is positioned as a significant advancement in the field, providing solutions to the challenges faced by current passive deployment strategies.
In summary, the report presents a groundbreaking approach to the deployment of ultra-lightweight space structures, showcasing the potential of ERF technology to revolutionize how these structures are managed in space missions. The work was conducted at the Jet Propulsion Laboratory, California Institute of Technology, under a contract with NASA, highlighting its importance in advancing aerospace engineering and technology.
