This report reviews the main problems encountered in the research and development of cryogenic materials for aerospace vehicles and superconducting machines. The problems are divided into three items: (1) the requirements to be considered for material selection, (2) the structural alloys recently developed for cryogenic service, (3) the mechanical behavior and structural stability of metals and alloys at cryogenic temperatures.
Recently, international activities have been developed in order to establish the international temperature scale (IPTS) in the region below 13.81K, i.e., the downward extension of fhe IPTS. This article gives a short survey of these efforts; -Main points of arguements at the Comité Consultatif de Thermométrie and its Working Groups, the present state of our knowledge of thermodynamic temperatures in the region under investigation, and survey of practical thermometers as candidates for the standard thermometer.
The largest space simulation chamber in Japan was completed last year at the Tsukuba Space Center of National Space Development Agency (NASDA). This chamber will be used for thermal-vacuum environmental test of artificial satellites planned to launch by NASDA hereafter. Chamber vessel is constructed by 304 stainless steel having inside diameter of 8.5m, height of 25m and volume of 1, 350m3. Cryopump at 20K was adopted as the main pump of vacuum pumping system together with titanium sublimation pumps and sputter ion pumps for preventing oil contamination. There are two cryopumps, namely main-cryopump and sub-crypoump, having pumping speed of 3×1061/sec and 2×1051/sec respectively. Pumping speed of subcryopump is adjustable in wide range. 2 sets of 5×1041/sec titamium pumps and 3 sets of 8001/sec ion pumps were installed. The chamber is evacuated to 10-9Torr within 8 hours by using these pumps. The OFF-AXIS type solar simulation system consists of 19 sets of 30Kw Xe arc lamps and a 5.5m parabolic collimating mirror. This solar simulator has the leading performance in the world. Many kinds of cryogenics, namely shroud cooled to 100K with liquid nitrogen for simulating cold and darkness of space, helium refrigerators for cryopump, play a major role in the space chamber system. In this paper the outline of the Tsukuba space chamber is explained placing emphasis on its cryogenic systems.