Triboelectric charging of Lunar Dust by Rover Wheels
Abstract
The presence of dust on the lunar surface has been identified as one of the key challenges for landed mission sand for establishing long-term human habitats. The risk of dust accumulation on photovoltaic and other mechanical or optical surfaces goes beyond mere coverage as the electrostatic charge buildup can affect the operations and lifetime of electrical components.
The dayside lunar regolith is exposed to solar UV radiation and the flow of solar wind plasma resulting in electrostatic charging of the surface. Small dust particles can collect sufficiently large charges, that combined with intense localized electric fields, are capable of overcoming adhesion and mobilizing or transporting the dust particles. In addition to plasma charging processes, grains can also become charged due to mechanical processes that generate triboelectric processes. For example, walking astronauts or turning wheels can generate unexpectedly large electric fields due to tribocharging, the efficient separation of positive and negative charges in the extremely dry lunar environment. This process is expected to be most efficient in unlit regions where the contributions of UV and plasma exposure are inefficient to provide discharging currents to limit the buildup of intense electric fields. Hence, missions visiting the resource rich permanently shadowed lunar regions will have to be prepared to mitigate the effects of tribocharging. In this presentation we report on the initial experimental investigation of the interaction between a rover wheel and two different lunar regolith simulants. We used the NASA AMES dust bed facility, a small remote-controlled rover with rubber wheels, and a calibrated Faraday Cup (FC) on the surface to measure the charge distribution of dust particles landing in our FC. We find that the dust particles forming the so-called "rooster tails", the cloud of particles forming behind the spinning wheels of a rover, are positively charged. We will report on the measure charge distribution and suggest ways to mitigate the triboelectric effects for rovers designed to explore lunar permanently shadowed regions to gauge their availability for in-situ resource utilization.- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.P33C..10Y
- Keywords:
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- 6205 Asteroids;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS;
- 6230 Martian satellites;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS;
- 6250 Moon;
- PLANETARY SCIENCES: SOLAR SYSTEM OBJECTS