Motivation:
International scientific and commercial interests in exploration missions to solar system bodies such as the Moon, asteroids and comets have increased significantly during the last two decades and will continue to increase in the future. One major environmental constraint during exploration missions is the presence of charged dust-like particles.
The effects of lunar dust on Extra-Vehicular Activity systems:
- external vision obscuration, false instrument readings, dust coating and contamination,
- loss of traction, clogging of mechanisms, abrasion, thermal control problems or seal failures.
One of the most serious effects is the compromising of astronaut health by irritation and inhalation of lunar dust. Dust exposure and inhalation could have a range of toxic effects on human lunar explorers, especially if longer exposure times become the norm during future manned exploration missions.
Objectives
The goal of DUSTER is to investigate in detail the charging and cohesion of the dust grain in the regolith, which is crucial to understanding the dust transport at the surface of airless bodies.
It addresses key questions about the surfacing of airless bodies as observed by telescopes and scientific probes, such as the formation of dust ponds and the dust haze at the limb of the moon observed by the astronaut during the Apollo missions.
It also addresses more engineering-oriented concerns regarding the adhesion of dust particles to man-made surfaces (spacecraft, instruments, spacesuits, solar panels, etc.). It also constitutes a first step toward a sensitive surface cleaning device.
Scientific objectives:
- Characterise dust particle charging as a function of their environment and properties (UV, plasma, dust particle properties) both theoretically and experimentally.
- Characterise dust particle transport due to electrostatic forces as a function of their environment and properties (UV, plasma, E-field, dust particle properties) both theoretically and experimentally (in laboratory).
- Determine the E-field needed to move charged dust particles depending on the particle and environmental properties. Improve existing dust particle charging and transportation models
- Develop the algorithms to retrieve the desired parameters from the instrument raw data
Intermediate steps
The physical quantities that will be measured by the instrument will be estimated by analytical models and/or simulation software. Then, using this theoretical data set and the experimental data acquired, the technical requirements and interfaces for the instrument will be defined.
The hardware sub-units and units that will constitute the breadboard instrument (front end electronics, High Voltage Power Supply unit, Low Voltage Power Supply unit, control and processing unit (including firmware), electrodes/probes, mechanical enclosure of the instrument) will be designed.
The breadboard software will be developed and the mechanical box will be designed and manufactured. Once the electronic units and sub-units have been designed, tested and validated, the goal will be to integrate the complete instrument (both mechanically and electronically) and validate its functionality and performance.
The test facility will be developed, the physical quantity ranges will be validated and the instrument will be tested. The test facility will consist of equipment that is able simulate an environment representative for the conditions on the Moon in terms of dust charging and transportation. It will allow to measure the electric field needed to move charged dust particles, the current resulting from their impact onto the dust electrodes and the charging level of those particles.
