Method for Inflating Uniformly Stiff Tubular Booms

Marshall Space Flight Center, Alabama

NASA's Marshall Space Flight Center (MSFC) developed a foam-rigidized, inflatable, tubular space boom that can be transported, deployed, and inflated at remote locations. The lightweight device consists of an inner and outer sleeve and, in its non-pressurized state, can be accordion-folded into a small storage canister. This allows for simple and compact transportation at a low cost.

Foam is injected between the inner and outer polyimide sleeves, while the inner cavity is pressurized. After the foam cures to rigidity, pressure is released, and the boom holds its shape.

The boom has a unique gas venting mechanism, allowing excess air and gas bubbles that form during the foam injection to escape without affecting the end product's hardened shape. The technology was initially created to build light, rigid structures for in-space applications, but can be used in other environments due to its naturally portable design, low weight, and low packaging volume requirements. Given its tubular shape, multiple boom structures can be combined to create complex structures such as a tripod, wall, or large rectangular prism.

The tubular boom has already been trialed and tested. Several articles have been fabricated at MSFC and tested for deployment, foam injection, and structural properties. The device consists of an inner bladder and an outer sleeve. These can be constructed with several materials, including polyimide film or a robust fabric with polymer lining. The tube includes two ends that are capped by lightweight polymer end plugs. The front-end plug has two or more input ports, and the back-end plug has two or more output ports. The first input leads to the internal bladder, where pumped-in air creates a core pressure. The second input leads to the outer sleeve, where liquid foam is injected and hardens.

As the foam enters, outputs at the back of the structure serve two purposes. First, they enable any residual air that remains in the outer sleeve to escape once the injection begins. Second, they vent any trapped gas formed while the foam cures, allowing the material to fill the tube and create a uniformly stiff structure. Once this process is finished, the internal pressure is released, and the boom is operational. The boom is thus able to retain its rigid structure without the need to sustain any internal pressure. Scalability is a major benefit of this technology, given that the boom diameter, wall thickness, and foam density can be customized for specific design requirements.

NASA's Technology Transfer Program offers commercial licensing agreements to ensure its pioneering research finds secondary uses that benefit the economy, create jobs, and improve quality of life. For more information about licensing, please contact Clark Darty at This email address is being protected from spambots. You need JavaScript enabled to view it. or 256-544-2728.