Deployment of inflatable space structures - A review of recent developments

This paper reviews recent advances and future challenges in analytical and experimental methods for understanding and verifying the deployment of inflatable structures in space. Concepts for free and controlled deployments are discussed and examples are cited. Prior experiences with ground and flight experiments are examined and the promise of predictive analytical models is reviewed. In the early stage of inflatable developments, analytical simulations of deployment were noticeably lagging because of the high degree of problem complexity. However, recent experiences with a number of engineering and phenomenological models show that these models are particularly useful in explaining the physics of deployment. The paper concludes with likely future directions on the best use of deployment tests and analytical simulations to enhance the low mass and volume advantages of inflatables with greater deployment reliability, and at the same time, minimize the use of massive complex control devices

Rarefied Pure Gas Transport in Non-Isothermal Porous Media: Effective Transport properties from Homogenization of the Kinetic Equation

Viscous flow, effusion, and thermal transpiration are the main gas transport modalities for a rarefied gas in a macro-porous medium. They have been well quantified only in the case of simple geometries. This paper develops a model based on the homogenization of kinetic equations producing effective transport properties (permeability, Knudsen diffusivity, thermal transpiration ratio) in any porous medium sample, as described e. g. by a digitized 3D image. The homogenization procedure -- neglecting the effect of gas density gradients on heat transfer through the solid -- leads to macroscopic transfer relations, and to closure problems in R^6 for the obtention of effective properties. Coherence of the approach with previous literature on the subject is discussed. The asymptotic limits of the model (rarefied and continuum regimes) are also studied. One of the main results is that the effect of the geometry on thermal transpiration has to be described by a tensor which is distinct from the permeability and Knudsen diffusion tensors