Currently existing approaches for deployment of large, ultra-lightweight gossamer structures in space rely typically upon electromechanical mechanisms and mechanically expandable or inflatable booms for deployment and to maintain them in a fully deployed, operational configuration. These support structures, with the associated deployment mechanisms, launch restraints, inflation systems, and controls, can comprise more than 90 percent of the total mass budget. In addition, they significantly increase the stowage volume, cost, and complexity.

A CHEM (cold hibernated elastic memory) membrane structure without any deployable mechanism and support booms/structure is deployed by using shape memory and elastic recovery. The use of CHEM micro-foams reinforced with carbon nanotubes is considered for thin-membrane structure applications. In this advanced structural concept, the CHEM membrane structure is warmed up to allow packaging and stowing prior to launch, and then cooled to induce hibernation of the internal restoring forces. In space, the membrane remembers its original shape and size when warmed up. After the internal restoring forces deploy the structure, it is then cooled to achieve rigidization. For this type of structure, the solar radiation could be utilized as the heat energy used for deployment and space ambient temperature for rigidization.

The overall simplicity of the CHEM self-deployable membrane is one of its greatest assets. In present approaches to space-deployable structures, the stowage and deployment are difficult and challenging, and introduce a significant risk, heavy mass, and high cost. Simple procedures provided by CHEM membrane greatly simplify the overall end-to-end process for designing, fabricating, deploying, and rigidizing large structures. The CHEM membrane avoids the complexities associated with other methods for deploying and rigidizing structures by eliminating deployable booms, deployment mechanisms, and inflation and control systems that can use up the majority of the mass budget.

In addition, highly integrated multifunctional CHEM membranes with embedded thin-film electronics, sensors, actuators, and power sources could be used to perform other spacecraft functions such as a communication, navigation, science gathering, and power generation.

This advanced membrane concept represents the introduction of a new generation of self-deployable structures. This technology will introduce a new paradigm for defining configurations for space-based structures and for defining future mission architectures. It will provide new standards for fabricating, stowing, deploying, and rigidizing large deployable structures in a simple, straightforward process.

A number of deployable structures are used for space robotics and other support deployable structures for solar sails, telecommunication, power, sensing, thermal control, impact, and radiation protection systems. A self-deployable membrane structure could be used on some of these space applications with a big improvement.

Although the space community is the major beneficiary, potential commercial applications are foreseen for this technology. It could be applied to deployable shelters, storage places, and camping tents. Other potential applications are seen in self-deployable house construction, thermal insulation, automotive, packaging, and biomedical.

This work was done by Witold M. Sokolowski and Paul B. Willis of Caltech and Seng C. Tan of Wright Materials Research Co. for NASA’s Jet Propulsion Laboratory. For more information, contact This email address is being protected from spambots. You need JavaScript enabled to view it.. NPO-41759

NASA Tech Briefs Magazine

This article first appeared in the September, 2010 issue of NASA Tech Briefs Magazine.

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