Lightweight shape memory self-deployable structures for Gossamer applications

A cold hibernated elastic memory (CHEM) structure technology is the most recent result of the quest for simple, reliable and low-cost expandable structures. The CHEM technology utilizes shape memory polymers in open cellular (foam) structure or sandwich structures made of shape memory polymer foam cores and polymeric composite skins. It takes advantage of polymer’s heat activated shape memory in addition to the foam’s elastic recovery to deploy a compacted structure. The glass transition temperature T g is tailored to rigidize the structure in the fully deployed configuration. The CHEM foam technology provides a simple end-to-end process for stowing, deployment and rigidization that has benefits of low mass, low cost, high reliability and great simplicity. The CHEM foam structures are under development by the California Institute of Technology’s Jet Propulsion Laboratory (JPL) and industry. Presently, the CHEM structure concept is well formulated with clear space and commercial applications. This paper describes these structures and their major advantages over other expandable/deployable structures. Previous experimental and analytical results were very encouraging, confirming the feasibility of this innovative, new class of deployable structure indicating that CHEM foam technology can perform robustly in the Earth environment as well as in space. Some potential space applications were studied under various programs at JPL with promising results. Further improvements in CHEM technology will widen potential space applications. Although space community is the major beneficiary, a lot of potential commercial applications are also foreseen for the Earth environment. These applications are briefly described in this paper as well.