Method for making a cryogenic tank joint

The present invention relates to joints for cryogenic liquid propellant tanks, and more particularly relates to a lightweight joint for carrying and transmitting high structural loads in multi-lobe cryogenic tanks. Improved joints for cryogenic liquid-containing tanks are disclosed. The joints include a support plate, a lower arm mounted on the support plate, an upper arm mounted on the support plate spaced from the lower arm, and tank skins extending into the space between the lower and upper arms. Sealing layers are provided between the tank skins and the joint arms. The joints are particularly useful for space launch vehicle cryogenic liquid propellant tanks which must be lightweight, withstand high structural loads and maintain leak-free conditions.