The Genesis Space Probe as a Platform for Materials Education
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THE GENESIS SPACE PROBE AS A PLATFORM FOR MATERIALS EDUCATION Charles C. Hays Division of Engineering and Applied Science California Institute of Technology, Pasadena, CA 91125 ABSTRACT NASA’s Genesis mission provides an interesting opportunity for educational outreach in a wide variety of materials related disciplines. This mission is one the Discovery planetary exploration series, and its purpose is to return to earth quantitative data regarding the composition of the Sun’s solar wind. In doing so, the mission requires a number of materials technology platforms that provide examples of how fundamental questions in science might be answered. Specifically, the Genesis mission provides an educational pathway showing how experiment design and the process of materials selection are combined to realize evidence that will increase our understanding of the cosmological transition from solar nebula to planetary bodies. INTRODUCTION The science of space and the development of space technology have impacted almost every aspect of our lives in today’s world. The exploration of space has been, and continues to be, one of the most visible of collaborative efforts between federal laboratories, industry, and academia. Genesis addresses questions about the materials and processes involved in the origins of the solar system by providing precise knowledge of solar isotopic and elemental compositions. The solar wind is a convenient source of solar matter readily available outside the terrestrial magnetosphere. Solar wind ions of interest (but, not all) are; 1) the lighter elements of the periodic table such as H, He, Li, and Be, 2) gaseous ions such as O, Ne, Xe, and Kr, and 3) elements from the transition series ; e.g., Mg, Ti, and Cr. The key consideration is that we should not expect qualitative 18 16 differences between the solar matter and that found on earth; e.g., all O vs. the O that we breathe on earth. However, there may be detectable differences in the relative isotopic 4 3 ratios of the solar wind ions; e.g., He /He . To quantitatively measure the differences, high-purity materials will be required due to the low abundance of solar wind ions. From an experimental standpoint, the collectors must be extremely pure so that the Genesis scientists can measure quantitatively, the difference between the concentrations of the implanted solar wind ions and the trace impurity levels present in the starting collector materials. Fortunately, solar wind ions have velocities in the well-understood ion implantation regime, and are retained upon striking passive collectors. This was demonstrated by the Apollo solar wind foil experiments [1]. The study of ionimplantation in a wide variety of materials is quite mature, especially in the semiconductor industry [2]. With 100-times longer exposure, and especially purer collector materials as compared to the Apollo foils, Genesis will provide precise solar isotopic compositions and greatly improved solar elemental composition for most of the periodic table. GG2.10.1
MISSION BACKGROUND AND TE
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