246. Weight Advantages of Pressure Supported Structures in Current and Future Space Vehicles

Paper

Abstract

This paper examines the advantages of pressure-supported structures in space vehicles. Large energy demands by spacecraft causes a need for huge propellant tanks that must be pressurized to meet engine requirements. Since this pressurization is built-in, the lightest weight tankage assembly is that which utilizes this pressure for structural rigidity under static as well as flight conditions.
This paper is concerned, chiefly, with that of lightest possible weight. The paper cover the structural build up of a cylindrical vessel that must bear high payloads under high accelerations, must absorb high thrust loads and large amounts of sonic vibration and more, and at the same time, this vessel must be lightweight as possible. It also covers best practices in bulkhead design, which close the ends of the tanks, tank lengthening for the purpose of carrying more propellant or tank sizing due to a need of currying propellants of different relative densities. Other topics touched on are the use of lamination of virtually all fasteners by employing the use of resistance welding, the reparability as another weight saver and also the future spacecraft called on to lift much higher loads from earth’s surface.
In conclusion, and only to support the contentions made in the paper, a comparison of Atlas with its major competitor discloses that the ratio between total propellant weights vs. total tank weight is 110 to 1 for Atlas and 50 to 1 for this competitor.