A pressure vessel composed of a titanium alloy. For a simple estimate, we took the pressure vessel as composed of a titanium alloy. In practice, composite overwrapped pressure vessels (COPVs) are typically used for xenon propellant storage. In a COPV, a gas-impermeable, metallic inner-liner is overwrapped with a strong, permeable carbon fiber overwrap such as Kevlar. The partnership between these materials could allow for a lighter pressure vessel. Residual gas in the adsorbent. A consideration for adsorbed gas storage is the residual gas trapped in the adsorbent at the desorption conditions. Studies on vehicular methane or hydrogen gas storage and delivery via adsorbents use the deliverable/usable capacity of the gas in the material-the density of gas in the material at the storage condition minus that at the discharge condition -as a performance metric for the material. The deliverable capacity accounts for the residual gas trapped in the material at the discharge pressure, which cannot be delivered. We assumed the deliverable/usable capacity of xenon in the adsorbent is equal to the adsorbed xenon density at the storage pressure because, in space, the discharge pressure corresponds to vacuum.