Simulating The Surface Morphology Of A Carbonaceous Chondrite Asteroid

• Main Authors: Covey, S. D., Lewis, J. S., Metzger, P. T., Britt, D. T., Wiggins, S. E.
• Format: Text
• Language: unknown
• Published: STARS 2016
• Subjects: Tagish; Tagish Lake
• Online Access: https://stars.library.ucf.edu/scopus2015/4204

One portion of our NASA contract "Task-Specific Asteroid Simulants for Ground Testing" was replicating the expected textures and morphology of asteroid materials. This paper reports preliminary results and procedures for the production of a prototype simulant. An asteroid analogue starts with an appropriate mixture of minerals. Our initial simulant was based upon the compositional analysis by Bland et al. (2004) of the Tagish Lake meteorite. These minerals were to be mixed and bound into the needed final form. The possible forms are those seen in the meteorite collection and photographic evidence from asteroid missions. These include (1) strongly consolidated cobbles or boulders; (2) weakly bound "dirt clod"-like structures; and (3) loose regolith soil with an appropriate particle size distribution. During the course of the project, we conducted a survey and an Asteroid Simulants Workshop to gather feedback from the simulants user community. One result of the survey and workshop was that our initial target meteorite type was changed to a CI chondrite, and specifically the Orgueil meteorite. We ground the source materials to particle sizes reported in meteorites and mixed them. At this stage, we had an acceptable "loose regolith" analog. Consolidation options included gentle consolidation to mimic a "dirt clod" hardness (perhaps 1 MPa). More strongly consolidated materials would mimic strong (compressive strengths >20 MPa) materials on asteroids. One challenge was in replicating the desiccation of millenia in space without over-heating the material and changing its chemistry; final drying included vacuum drying. Simulants were produced as loose regolith, small cobbles/boulders, or flat surfaces depending upon the simulant need. For some uses, a combination of the above was appropriate.