The Demand for In Situ Metrology in Microgravity R&D—Redefining Dynamic Processes and Technology Innovation

R&D in space provides a unique opportunity to benefit life by advancing science and technology in ways not possible in unit gravity conditions. For a decade, research on the International Space Station (ISS) has unveiled alternate outcomes of physicochemical phenomena from those known to occur on Earth. For instance, it is well established that the microgravity environment nearly eliminates density-driven segregation in dynamic processes that can result in nucleation processes with better monodispersity, more uniform structures<u>,</u> and homogenous materials leading to superior properties. Similarly, buoyancy-driven convection is negligible in microgravity making diffusion the predominant transport process. All the above affects interfacial energies and dynamics resulting in different surface energies, surface tension, heat and mass transport rates, crystallization kinetics, multiphase system dynamics, fluid dynamics, etc.; yielding novel materials structures and scientific possibilities.<br/>Analytical capabilities are key to understanding and controlling the dynamics of materials synthesis and assembly that result in some of the most advanced science and products developed in space. In this account<u>,</u> the ISS National Laboratory presents examples of technological breakthroughs that were realized by in-situ characterization, data analysis and process optimization on orbit. From industrial applications such as advanced optical systems and additive manufacturing to biomedical applications like protein crystal growth and tissue engineering, the need for in-situ characterization and in-situ process metrology has become essential for the success and acceleration of projects flown to station. Moreover, capabilities to enable in-situ surface and microanalysis, chemical analysis, spectroscopy, and other advanced imaging techniques are discussed.