1 Measuring the Fidelity of Asteroid Regolith and Cobble Simulants Philip T. Metzger, Florida Space Institute, University of Central Florida, Orlando, Florida, USA, Philip.T.Metzger@ucf.edu Daniel T. Britt, Department of Physics, University of Central Florida, Orlando, Florida, USA Stephen Covey, Deep Space Industries, Inc., 6557 Hazeltine National Dr., Orlando, FL 32822 Cody Schultz, Department of Physics, University of Central Florida, Orlando, Florida, USA Kevin M. Cannon, Department of Physics, University of Central Florida, Orlando, Florida, USA Kevin D. Grossman, Granular Mechanics and Regolith Operations, Engineering and Technology Directorate, NASA Kennedy Space Center James G. Mantovani, Granular Mechanics and Regolith Operations, Engineering and Technology Directorate, NASA Kennedy Space Center Robert P. Mueller, Granular Mechanics and Regolith Operations, Engineering and Technology Directorate, NASA Kennedy Space Center Abstract NASA has developed a “Figure of Merit” method to grade the fidelity of lunar simulants for scientific and engineering purposes. Here we extend the method to grade asteroid simulants, both regolith and cobble variety, and we apply the method to the newly developed asteroid regolith and cobble simulant UCF/DSI-CI-2. The reference material that is used to evaluate this simulant for most asteroid properties is the Orgueil meteorite. Those properties are the mineralogical and elemental composition, grain density, bulk density of cobbles, magnetic susceptibility, mechanical strength of cobbles, and volatile release patterns. To evaluate the regolith simulant’s particle sizing we use a reference model that was based upon the sample returned from Itokawa by Hayabusa, the boulder count on Hayabusa, and four cases of disrupted asteroids that indicate particle sizing of the subsurface material. Compared to these references, the simulant has high figures of merit, indicating it is a good choice for a wide range of scientific and engineering applications. We recommend this methodology to the wider asteroid community and in the near future will apply it to additional asteroid simulants currently under development. Keywords: Asteroids, surfaces; Regoliths; Meteorites. I. Introduction Extraterrestrial Simulants are simulated space materials: geological materials of extraterrestrial bodies including crystalline solids in the form of dust, regolith, boulders, and ice. Simulants are used because there is a large gap between the amount of space materials needed for research and technology development and the amount actually available in the meteorite collection or sample return. Simulants are beneficial for more than one reason. The obvious one is that a simulant can