MaTErIals SCIENCE& ENGINEERING A ELSEVIER Materials Science and Engineering A 413-414 (2005) 592-597 www.elsevier.com/locate/msea Processing of lunar soil simulant for space exploration applications Subhayu Sen a,*, Chandra S. Ray b, Ramana G. Reddy c a BAE SYS/NASA Marshall Space Flight Center, Huntsville, AI 35801,USA b NASA Marshall Space Flight Center, Huntsville, Al 35801, USA The University of Alabama, Tuscaloosa, Al 35487, USA Received in revised form 22 July 2005 Abstract NASA's long-term vision for space exploration includes developing human habitats and conducting scientific investigations on planetary bodies, especially on Moon and Mars. To reduce the level of upmass, processing and utilization of planetary in situ resources is recognized as an important element of this vision. Within this scope and context, we have undertaken a general effort aimed primarily at extracting and refining metals, developing glass, glass-ceramic or traditional ceramic type materials using lunar soil simulants. In this paper we will present the preliminary results on our effort on carbothermal reduction of oxides for elemental extraction and zone refining for obtaining high-purity metals. In addition, we will demonstrate the possibility of developing glasses from lunar soil simulant for fixing the nuclear waste from potential nuclear power generators on planetary bodies. Compositional analysis, X-ray diffraction patterns and differential thermal analysis (DTA) of processed samples are presented. 2005 Elsevier B.V. All rights reserved. Keywords:In situ resource utilization; Regolith; Simulant; Extraction; Purification; Glass fabrication 1. Introduction Since at the present time a long-duration human presence on the Moon appears to be the stated priority of the space explo- The new solar system exploration initiative has chartered ration vision, a brief discussion on the resources available on the NASA to establish a self-sufficient, affordable and safe human Moon is mandated. The lunar atmosphere is often described as a and roboticpresence outsidethe low earth orbit includingthe hard vacuum since the gas concentration varies between 105 to Moon and Mars [1]. Some of the essential items required for 104 molecules/cm3 [4]. This is approximately 14 orders of mag- a self-sufficient extra-terrestrial habitat include materials for nitude less than in the earth's atmosphere. In the absence of any crew life support, power generation and habitat construction. atmosphere,thelunarregolithbecomestheprimary sourcefor In this context processing and utilization of in situ resources on the in situ resources. The term regolith is used to define the first a nonterrestrial body becomes an integral part of the exploration 4-15 m of lunar soil that has been derived from fragmentation vision.This approach would reduce the upmass significantly of the bedrock by large and small meteoritic impacts [5]. The that would otherwise have to be transferred from earth. Using major components of the lunar regolith consist of the fragments the Si present in the lunar soil or regolith to fabricate thin-film of rocks, minerals and glasses. The samples returned from the solarcellsforelectricalpowergenerationisonesuchexam- Apollo and Luna missions were predominantly from two geolog- ple [2]. In the case of lunar nuclear power, immobilizing the ical terrains of the Moon, namely the maria or the great flat plains nuclear waste generated from the nuclear power plants in a glass and highlands or mountainous regions [4,5]. The major group preparedfromlunarregolithisanothersuchexample.Thepossi- ofmineralsfoundonthelunarsurfaceconsistsofsilicateminer- bility of extracting structurai metais and producing refractories ais, namely olivine, pyroxene and piagiociase, and non-silicate andglassesfromnonterrestrialresourceshas alsobeenproposed minerals, such as ilmenite [5]. The average soil composition of [3]. these two terrains is summarized in Table 1 and shows that there is diversityin