Abstract: A combined space vehicle fuel cell and modular space station structural building component which provides containment of propellants during launch and thereafter provides one of a plurality of modules which can be interconnected once orbit is achieved for constructing a space station or space platform. The combined space vehicle fuel cell and modular space station structural building component is configured so that a first pressure vessel for containment of one propellant is preferably concentrically positioned within a second pressure vessel for another propellant, which can result in a shorter fuel cell. Intervessel structure is included for interconnecting the pressure vessels but is lightweight due to the concentric configuration of the pressure vessels and is preferably concentrated in the aft end of the fuel cell for providing a rigid structure for receiving thrust through any and all thrust attaches to a spacecraft.