This proposal discloses an innovative, economically feasible technique to capture and re-liquefy the hydrogen boil-off by using carbon nanotube adsorption prior to liquefaction. The hydrogen boil- off involves an average of 10,300 SCFM of hydrogen vapor at pressures below 17 psia for a period of an hour. The configuration disclosed in the proposal significantly reduces the size of the liquefaction equipment and this translates into a substantial reduction in cost for the system. Preliminary calculations have indicated that a payback period of less than 12 months (based on the current cost of hydrogen and the use rate at KSC when shuttles return to flight). The Phase I effort will also experimentally demonstrate the performance of a carbon nanotube coated (CNC) adsorption bed in Phase I. This proposal discloses a patent-pending approach which makes this technology feasible, safe and affordable. The Phase I effort is significant, in that an extensive demonstration of the performance, cost, durability, and simplicity of the CNC adsorption bed as well as a demonstration of the economic benefits of the hydrogen capture system for NASA/KSC will both be achieved before proceeding to Phase II.