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In recent years there has been an increasing interest in CubeSats platforms. Due to their low cost and flexibility, these platforms have been used for different missions such as Earths environmental protection, agriculture monitoring, prevention of natural disasters, homeland security, and border control. Other applications include scientific experiments or technology, space exploration, observation of the universe, astrophysics, biology, or physical sciences in microgravity. In order to make this technology affordable to universities, research centers, and space companies, the recovery and reuse of these platforms are of fundamental importance. However, the design and development of a platform capable of surviving an atmospheric entry is a challenging problem. Special care has to be taken so that the entry vehicle can decelerate sufficiently and dissipate the large heat load experienced from traveling through the atmosphere. In order to accomplish this goal, external insulation materials composed of a rigid aeroshell have been commonly used in spacecraft. Reinforced carbon-carbon, low- and high-temperature reusable surface insulation tiles, and felt reusable surface insulation blankets are just some of the materials that have been employed to protect the space vehicles during the harsh re-entry environment. With the advance of manufacturing processes and the development of flexible high-temperature materials, a new trend has emerged: the use of Inflatable Aerodynamic Decelerators (IAD). IAD technology is of great interest because such devices inflate to their full size in space and are not directly constrained by the launch vehicle payload shroud diameter nor inflation conditions like parachutes. Nonetheless, as the inflation or deployment of IAD devices occurs at high altitudes, continuum-based models or high enthalpy ground test facilities have limitations in the prediction of the correct flowfield physics and aerothermodynamic characterization of these devices. At rarefied atmosphere, the particulate-like behavior of the gas becomes more important, and specialized computational techniques that are derived from the statistical mechanics representation of the behavior of the individual particles are necessary to solve a flow around the reentry object. The most successful of these techniques is direct simulation Monte Carlo (DSMC) method. In this scenario, the present work aims to investigate the impact of rarefied hypersonic flows over three different configuration IAD configuration using the DSMC method. The correct understanding of the aerodynamic forces and heating fluxes have a direct impact on the development of IAD systems for CubeSats reentry and recovery. The primary goal of this work is to investigate the influence of reentry altitude on the flowfield structure, aerodynamic properties, shock wave structure, as well as the wake region, formed downstream of the vehicle. |
