A large, lightweight, economical, easy-to-manufacture human-habitation module that is well suited to long-term use in outer space has been developed. Modules like this one have potential for commercial applications, including the provision of human habitats for the commercialization of outer space and for shelter against such hostile environments as frigid polar regions, high altitude (airborne or on mountains), and underwater. For government purposes, a module like this one can serve as a "TransHab" (a human-habitation module for transit from the surface of the Earth to low orbit around the Earth), or as a habitation or laboratory module on the International Space Station, the surface of Mars, or the surface of the Moon. Indeed a module like this one could eventually be used as a free-flying laboratory in which to conduct long-duration outer-space research.

The volume of the module is 500 m3 (approximately twice that of the space shuttle payload bay) and can easily be increased. The module is a hybrid of an inflatable shell with a hard central structural core — an advanced structure that exploits the packaging and mass efficiencies of its inflatable structure, and the advantage of preintegration afforded by a hard-structured habitat.

Heretofore, human-habitat modules have included such hard, metallic structures as those of the Skylab, Mir, and other missions. Unfortunately, the designs of these modules have been constrained by considerations of weight and cost. They have also been subject to volume constraints: Because each such habitat module was built from a metallic primary structure, its usable volume was limited because a payload must fit within a specified launch rocket. Hence, whenever mission requirements dictated the need for a large usable volume that exceeded the capability of existing launch rockets, a common solution was to design new launch rockets and facilities. This solution significantly increased the cost associated with unique missions and gave rise to large financial investments in single-use vehicles. Moreover, to counteract the inherent tendency of large structures toward dynamic-load-amplification and buckling failure modes, it was necessary to make these structures even heavier. The resulting increases in weight drove launch-rocket requirements and further exacerbated the problems of the development and costs of new launch rockets.

The present advanced rigid/inflatable hybrid spacecraft habitation module is the product of an attempt to overcome the disadvantages of prior designs. This module contains a fully closed regenerative life-support system, wherein all air and water are reused. Other features of the module include thermal control; crew accommodations; protection against ionizing radiation; avionics; electronic circuitry for command, communications, and control; guidance and navigation equipment; protection against meteoroids and orbital debris (M/OD protection); and an airlock for entry and exit by the human inhabitants. All of the equipment systems that implement these features are stored on lightweight, removable structural shelves, which, collectively, constitute a major structural component of a central structural core.

Prior to launch, an inflatable shell, with an attached M/OD protection, is collapsed and folded around the central structural core. The entire structure is then ready to be strapped onto a lightweight composite carrier that is, for pres-ent purposes, held in the space-shuttle payload bay by payload-retention latches. The space shuttle then transports the module to low orbit around the Earth. Once in orbit, the module is removed from the payload bay and its inflatable shell with M/OD protection inflated to full volume. Once the shell is fully inflated, the various systems and subsystems (e.g., food, crew accommodations, avionics, and the like) that have been stored on the lightweight structural shelves are repositioned to the internal configuration required for a Mars TransHab, the International Space Station, or other application.

As the advanced rigid/inflatable hybrid module has been described thus far, it can readily be seen to offer advantages, over older modules, of lighter weight, larger volume, greater ease of fabrication, and associated lower cost; these advantages are expected to ensure the leading role of modules like this one in long-duration spaceflight. It also offers the additional advantage of reconfigurability. Moreover, notwithstanding its inflatability, the shell is sufficiently thick and stiff that it would maintain its inflated shape in the event of a sudden depressurization.

This work was done by William C. Schneider, Horatio M. De La Fuente, Gregg Edeen, Kriss J. Kennedy, James Lester, Linda Hess, Chin Lin, and Richard H. Malecki of Johnson Space Center and Shalini Gupta of Lockheed Martin.

This invention is owned by NASA, and a patent application has been filed. Inquiries concerning nonexclusive or exclusive license for its commercial development should be addressed to the Patent Counsel, Johnson Space Center, (281) 483-0837. Refer to MSC-22900.

NASA Tech Briefs Magazine

This article first appeared in the January, 2001 issue of NASA Tech Briefs Magazine.

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