NASA Johnson Space Center

2000

The state of the art material and technologies available for the flexible envelope materials for Inflatable systems have been emphasized in this paper. Inflatables such as Aerostats, Radome and Floats and their material property requirements have been discussed. The paper throws some light on the basis of selection of raw materials such as fabric substrate, coating polymer, grades of films for specific applications, based on their property mix. An overview of different sealing techniques used for fabrication of inflatable structures such as heat, RF, adhesive has been discussed along with coating and lamination techniques suitable for manufacturing such fabrics.

Journal of Spacecraft and Rockets, 2011

The Rigidizable Inflatable GetAway Special EXperiment (RIGEX) was run successfully on board STS-123 (Endeavor) in March 2008. RIGEX was built by graduate students at the Air Force Institute of Technology (AFIT) and returned there following the shuttle flight for post-flight analysis. The experiment's objectives were to demonstrate in space the stowage, deployment, and rigidization techniques of carbon fiber composite inflatable rigidizable cylindrical booms. RIGEX was a Canister For All Payloads (CAPE) Space Shuttle cargo bay experiment designed to heat and inflate three 50.8 cm (20 in) long carbon fiber composite booms in a microgravity vacuum environment and measure both the structural characteristics and the deployment accuracy. Pressure, temperature, modal response, and position data were collected successfully on-orbit and are compared here to ground test data. This research is intended to help demonstrate the feasibility of using lightweight and low stowage volume (high packaging ratio) inflatable/rigidizable space structures for space mission applications. NFLATABLE space structures have long been acknowledged as a means of reducing complexity, weight, volume, and cost of large space systems. Beginning with the limited launch capabilities of the early space program, inflatable structures were used successfully in orbit multiple times. 1 Lack of understanding of the deployment processes in space coupled with large increases in space lift capacity led to the early space community to use more familiar metal structures. Spacecraft complexity has increased with increasing demands levied on space systems' performance, which drives increases in spacecraft weight and volume. It can be shown that increasing weight and volume increases overall spacecraft cost and launch cost, while limiting the potential number of space lift providers. 2 As in the early space program, inflatable structures are again being investigated to reduce spacecraft weight, volume, and cost. As before, inflatable space structures still present many challenges, such as maintaining internal pressure for structural integrity. Though recent inflatable space experiments have lasted several years 3 without mission ending pressure loss events, it is conceivable that pressure loss could weaken the entire structure, possibly ending the mission. For a purely inflatable structure-one without any rigid components-there are few means to combat this limitation. An alternative to continual pressurization is to rigidize the structure after inflation. Currently, the majority of the work associated with inflatable/rigidizable space structures has been confined to computer modeling and ground testing of deployment and structural characteristics. 4

Computational Methods in Applied Sciences, 2008

The building materials that help designers or architects achieve their goal of defining and enclosing space are usually concrete, steel, glass or wood. For these materials designers have both empirical data gained from experience and at times complex calculation methods enabling them to use them in their designs in a tangible, reckonable and, consequently, almost risk-free manner. It seems obvious that creating a design with well-known building materials will lead to more or less predictable outcomes. This is a good reason for investigating a design process dealing with air-filled building-elements. Architectural structures look completely different when one employs a “building material” which has been subjected to neither detailed investigations nor sophisticated calculations. The “Smart_Air” Design Studio was devised to take a closer look at the unusual building material “air”, which we have only just begun to explore, and to make it the centre of a focused design exercise. The objective was to use “air”, or, rather, pneumatic technologies, to arrive at structurally sound solutions for enclosing space, which could be considered to be a “roof” in the widest sense of the term.

AccessScience

This review presents the developments in inflatable structure technology that may be utilized as the basis for the construction of a space tower. Conventional construction technology is not appropriate for the construction of a space tower as traditional steel-reinforced concrete structure technology is prohibitively heavy, cumbersome and expensive. By contrast, these new emerging technologies, based on inflatable structure systems can potentially solve design, control and load carrying capacity problems. Successive developments in inflatable land structures and inflatable structures for space applications are reviewed and their applicability for the construction of a space tower is assessed.

Acta Astronautica, 2010

Lightweight, efficient packaging and large operational size in space are the ideal requirements in gossamer structures and membrane materials. Several kinds of these structures were built over the years as demonstrators of spacecraft subsystems. The difficulty to foresee the response of these components during the deployment and/or inflation phase in space or microgravity environments has increased the efforts to simulate their behavior. The aim of this work is to present a collection of analyses performed by finite element approaches on some benchmark cases set up by the European Space Agency. These cases have the purpose of both assessing reliable numerical methods and software packages and providing solutions for some basic engineering problems in this field. The considered cases are listed below and include different phenomena: pressurization and bending deflection of a structure in space in the presence of microgravity environment, deployment analysis of inflated structures, prediction of the wrinkling pattern and the wrinkles amplitude of thin membrane subjected to shear loading along the edges.

In reaction to the prevalent space design paradigm, we would like to explore a combination of transparent polymer laminate membranes and high tensile strength webbing as the envelope of future transparent space habitats. Further study reveals fascinating possibilities in the use a tensegrity structures as the exo-or endoskeleton for such envelopes.

In space we find an extreem vacuum. Human beings need an atmosphere to survive. This makes inflatables most apt for use in human space flight. Savings in weight and packaging volume are perfect for getting them off ground. With the development of TransHab, NASA made a big step forward in proofing the technology-readiness of using inflatables for human space habitat. Protection of micro-meteorites and radiation proofed to be even better than in the aluminium ISS Module. The shape of TransHab was based on a toroid. The sphere is the natural shape of a flexible skin with an inside pressure and naturally combining maximum volume with minimum surface (insulation/protection etc). It is astonishing why this very efficient shape has not been used more often for space applications. This paper will investigate on a concept level the possibilities of a sphere for use in microgravity and planetary habitats. Possibilities for habitats for 1-2 person, 6 persons and up to sixty and more, all using...