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The reason we perform materials science experiments in space is straightforward. It is because we want to improve materials that are made on Earth. The significantly reduced gravity environment of space allows unique science experiments to be performed. In most cases, these experiments cannot be done on the ground.

On Earth, a number of gravity-driven phenomena are operative which often lead to some unwanted or deleterious effects during materials processing.The phenomena being referred to are buoyancy, convection, sedimentation and hydrostatic pressure variation and they affect virtually all processes involving fluid phases. To find out more about these physical phenomena, please click on the four pictures below.

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In a reduced gravity environment, onboard the International Space Station for example, the four physical phenomena shown above are significantly suppressed. This means that objects do not experience any buoyancy forces when immersed in liquid, heavy solid particles do not sediment in a liquid, gravity-driven convection does not occur when a liquid is heated and the pressure in a liquid column does not increase with depth.

Under these very different conditions, it is possible to perform carefully controlled scientific experiments that will give us greater insight into the way that crystalline and amorphous materials form. Researchers will then truly understand how the detailed microstructure of metals develop (see picture below) and how gravity influences industrial processes, such as casting of alloys or semiconductor crystal growth.