Extracting Respirable Particles from Lunar Regolith for Toxicology Studies B. L. Cooper 1 , .D.S. McKay 2 , L.A. Taylor 3 , H. Kawamoto 4 , L.M. Riofrio 1 , and C.P. Gonzalez 5 1 Oceaneering Space Systems, Houston TX 77058; PH (281) 686-6821; email: bonnie.l.cooper@nasa.gov ; 2 NASA Lyndon B. Johnson Space Center, 2101 NASA Parkway, Houston TX 77058; 3 Planetary Geosciences Institute, University of Tennessee, Knoxville TN; 4 Waseda University, Tokyo, Japan; 5 Jacobs ESCG, Houston TX ABSTRACT The Lunar Airborne Dust Toxicity Assessment Group (LADTAG) is working to determine the permissible limits for exposure to lunar dust. This standard will guide the design of airlocks and ports for EVA, as well as the requirements for filtering and monitoring the atmosphere in habitable vehicles and other modules. Rodent toxicity testing will be done using the respirable fraction of actual lunar soils (particles with physical size of less than 2.5 micrometers). We are currently separating this fine material from the coarser material that comprises >95% of the mass of each soil sample. Sieving is not practical in this size range, so a new system was developed for this task. Collection and separation efficiencies are tracked as development and tests proceed. LADTAG’s recommendation for permissible exposure limits will be delivered to the Constellation Program in 2010. LADTAG RESEARCH During the Apollo missions, crewmembers were briefly exposed to dust in the lunar module, brought in after extravehicular activity. When the lunar ascent module returned to micro-gravity, the dust that had settled on the floor now floated into the air and caused eye discomfort and occasional respiratory symptoms. When the dust was bothersome, the crew donned their helmets and waited for the air revitalization system to remove the dust. Because our goal is to set an exposure standard for 6 months of episodic exposure to lunar dust (presumably after each EVA), the brief astronaut exposures of a few days are not conclusive. Based on experience with industrial minerals such as sandblasting quartz, an exposure of several months may cause serious damage, while a short exposure may cause none. WHY RESPIRABLE PARTICLES MUST BE SEPARATED PRIOR TO TESTING The equipment that is used for inhalation toxicology studies is designed to accommodate particles of respirable size. Larger particles mixed in with the smaller ones would block the flow lines used in the animal tests, and the tests would not be directly comparable with published data on other kinds of respirable material, used in silicosis and nanoparticle toxicity studies. Thus it is necessary for us to separate out the respirable fraction of lunar dust (particles less than 2.5 m diameter) from a bulk sample of lunar 66 Earth and Space 2010: Engineering, Science, Construction, and Operations in Challenging Environments © 2010 ASCE