Laboratory investigations of triboelectric charging of dust by rover wheels

Abstract

The dusty plasma environments of airless bodies present challenges for both exploration and science missions to their surfaces. Objects moving on the surface, such as rover wheels, transfer charges onto regolith dust due to the triboelectric effect. The charged dust particles can readily stick to spacesuits as well as the optical, electronic, and mechanical components of equipment and instruments, causing their degradation. This effect is more pronounced in permanently shadowed regions (PSRs) of the Moon, where the charge dissipation rate is low due to a lack of ambient plasma. Here we report the first results of an experimental investigation of the tribocharging effect between dust and rover wheels. Various wheel surface materials along the triboelectric series are selected. The effects of varying wheel speeds and dust types are explored. Results indicate that charge distributions conform to the triboelectric properties of the dust and material it comes into contact with. High charges of up to ∼2 pC are measured on dust grains ∼100 μm in diameter, which is equivalent to a surface potential of few hundred volts. Results also suggest that higher wheel speeds may result in more dust-dust interactions, changing the charging behavior of the dust grains. These findings indicate a need for future studies to better understand tribocharging in various exploration scenarios in order to design effective dust mitigation strategies and methods.