Abstract: An improved fuel tank for a lifting body re-entry vehicle having a particular external shape comprising four elongated lobes each having an external surface, each of the external surfaces having selected cylindrical and conical shapes, the lobes being selectively mateable to form a combined external configuration having a multiplicity of cylindrical and conical shapes conformable to at least a portion of the external shape of the vehicle. The cylindrical and conical shapes have variable radii at selected cross-sections thereof, such radii being selected for forming the external configuration. In a particular embodiment, the fuel tank has an initial portion, a midsection portion and a final portion and the cross-sectional shape of the initial portion of the fuel tank is that of two overlapping circles whose centers are positioned above one another, each of the circles being formed by two of the four lobes.