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.
NASA intends to send astronauts to a near Earth object (NEO) in or around 2025. This is expected to involve a six month mission with a few weeks stay-time at the NEO. Problems with this concept include lack of abort modes, vulnerability to solar flares, and lack of resupply opportunities. Studies by the authors (the Asteroid Mining Group) and a recent workshop at JPL organized by the Keck Institute opens the door to an alternative that addresses these problems and creates additional opportunities. Both groups investigated the feasibility of bringing one of more small NEOs into Earth or Lunar orbit. Particularly for High Earth Orbits (HEO) or High Lunar Orbits (HLO), this appears feasible with near-term technology, especially high-propellant-velocity, low-thrust solar electric propulsion (SEP) inspace vehicles. This paper compares the currently planned mission with an alternative: bringing one or more NEOs into HEO or HLO using SEP and lunar gravity assist. An astronaut mission to the NEO is then similar to a mission to the Moon without a landing. Trip times are measured in days, the NEO can be used for solar flare protection for most of the mission, and resupply within a few days is practical. Furthermore, materials derived from the NEO, e.g., propellant, water, radiation shielding, metals, silicon, and others, are available for projects in cis-lunar space, including satellite refueling, habitats, and space solar power. The alternative mission also develops much of the technology, experience, and infrastructure needed to protect Earth from potentially hazardous NEOs. As an outcome of these studies we are proposing a process whereby early missions can lead to large-scale industrialization of cis-lunar space based on solar energy and asteroidal resources.
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