Regolith Instability Caused By Gas Diffusion: A Case Study Of The Asteroid Redirect Mission

Abstract

Exhaust-regolith interactions are a particular concern for any mission operating near a small body. Ejected soil can damage sensitive systems such as solar panels or cameras. We seek to quantify risk to the NASA's Asteroid Redirect Mission (ARM) should thrusting near the target's surface become necessary. We have developed a program to model gas diffusion into asteroid regolith and determine potential instability from resulting pressure gradients. This behavior is calculated using Darcy's Law, which governs gas diffusion in a porous medium. Soil instability occurs when gas pressure gradients overcome weight and cohesive forces. We term the cohesion value necessary to maintain regolith stability critical cohesion. Due to uncertainty in asteroid properties, this value is calculated for a wide range of regolith parameters. For a nominal engine starting height of 7 meters, actual soil cohesion must be 0.4 Pa to prevent soil ejection. Since this value is two orders of magnitude below best estimates of actual regolith cohesion, we judge hazardous plume effects to be highly unlikely.

Publication Date

1-1-2016

Publication Title

Earth and Space 2016: Engineering for Extreme Environments - Proceedings of the 15th Biennial International Conference on Engineering, Science, Construction, and Operations in Challenging Environments

Number of Pages

67-73

Document Type

Article; Proceedings Paper

Personal Identifier

scopus

DOI Link

https://doi.org/10.1061/9780784479971.008

Socpus ID

85025703301 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/85025703301

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