Investigations on solidifying transparent model alloys have served frequently to gain knowledge on physical phenomena occurring during solidification of metallic alloys. However, quantitative results were only possible to obtain in thin samples where convection can successfully be suppressed. Quantitative studies on three dimensional phenomena not being affected by natural convection are thus only possible under microgravity conditions. Therefore, the European Space Agency (ESA) is planning to launch a new insert for the Material Science Glovebox (MSG) on board of the International Space Station (ISS) for studies on solidification phenomena in thick samples. Four different classes of transparent model alloys will be used to address the following scientific topics: (i) Columnar to Equiaxed Transition in Solidification Processing, (ii)Novel Peritectic Structures and In-Situ Composites; (iii) Solidification alongan Eutectic Path in Binary Alloys; and (iv) Solidification along an Eutectic Path in Ternary Alloys. Here, we give details on the scientific objectives and the operational features ESA's new solidification device will offer.