Abstract: A vehicle-mounted double-walled ellipsoidal cryogenic storage vessel includes an inner vessel enclosed by an outer shell to form an insulation chamber therebetween. Both the inner vessel and the outer shell are formed in the same manner. An elliptical pressure head of circular cross-section is cut along a diameter to form two end halves. An end wall is secured between the two end halves to form an end, which is secured to an end of a wall like cross-section. This process is repeated with another pressure head to form the other end of the storage vessel. Storage vessels may be constructed of any size desired to allow sufficient ground clearance when mounted under a vehicle.