We investigate the feasibility of an alternative xenon storage strategy, with the objective of reducing the mass of the storage materials required to carry the xenon propellant into space: packing the pressure vessel with a porous adsorbent material to help densify the xenon (i.e, use an adsorbent in combination with pressurization). Activated carbon has been investigated for adsorbed xenon propellant storage, but it does not reduce the mass of the storage system . Newer classes of nanoporous materials, such as metal-organic frameworks (MOFs) , porous organic cages (POCs) , and covalent organic frameworks (COFs) , exhibit very high internal surface areas and have demonstrated promise for gas densification in the context of vehicular hydrogen and methane storage , motivating us to consider these advanced nanoporous materials for adsorbed xenon propellant storage. Moreover, several of these nanoporous materials exhibit a high affinity for xenon, evidenced by their adsorptive selectivity for xenon in the context of separations .