This experiment will establish the structural changes that occur in Amorphous Solid Water (ASW), a porous material that can be formed by vapour-depositing water onto a cold plate. We will study the temperature and temporal evolution of this metastable condensed-matter material, particularly in an astrophysical context, looking at how the pores within the ice change size, shape and spacing, depending on the temperature. The experiment exploits the unique Q-range capabilities of NIMROD, capable of determining both the micro- and meso-scale structure of samples concurrently. The results will be of importance in understanding the properties of ASW, the most commonly encountered form of water in the universe, and how the ice structure at low temperatures impacts on the chemistry and physics that can be occurring during planet and star formation.