Practical Problems in Design of High-Performance Multilayer Insulation System for Cryogenic Stages
In order to store cryogenic propellants in orbit for any length of time, a high-performance insulation system is required. In this paper an insulation system will be defined as the insulating material, the means of attaching it, and the method to provide the vacuum within the insulation. The insulating material which offers the highest thermal performance is the multilayer type (frequently referred to as superinsulation). Several different kinds of multilayer insulation are available and have been applied to ground dewars. However, the application to space vehicles introduces new problems and requires additional development work. Many insulating schemes using multilayer insulation have been proposed for cryogenic spacecraft. Knoll and Oglebay have evaluated the insulating schemes in terms of their thermal efficiencies and discussed some of their inherent faults. Of the schemes proposed, the evacuated flexible-jacket scheme using a spacer-type multilayer insulation was considered to be in the most advanced state of development. Basic calorimeter data on the thermal properties of the spacer-type insulation material were available and a system employing the flexible-jacket scheme had been applied to experimental tankage [2–3]. The next logical step was the incorporation of this scheme into a workable insulation system for operational, flight-type tankage; therefore, an extensive program was begun to design such a system for a lunar mission stage. The emphasis was placed on solving the practical problems associated with producing a complete insulation system. To solve these problems, a series of flight-type tanks, and supporting experiments were planned. At present, two tanks have been designed and fabricated.
KeywordsInsulation System Lunar Mission Multilayer Insulation Tank Surface Propellant Tank
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