Martian Dust Transport

Participants: Jonathan Merrison, Haraldur Pall Gunnlaugsson, Per Nørnberg

Background

Mars seen from Hubble telescope

Mars is covered by fine red dust. It gives the planet its characteristic colour. The dust is ever present in the atmosphere, dominating the weather and sometimes becoming so thick that it plunges the planet into darkness. Its origin, its physical, chemical and geological properties have all yet to be fully understood.

With the help of simulators, modelling and the development of new instrumentation, researchers can get a deeper understanding of the dusty environment on Mars and help to solve some of the mysteries of the planet.

Experimental Facilities

Central to this research has been the development of two unique re-circulating wind tunnels housed in environmental chambers. Here parameters such as: gas pressure, gas composition, temperature and wind conditions can be controlled to reproduce those found on Mars, importantly special analogue dust can be injected to simulate the Martian atmospheric aerosol. Experiments can be set up or flight instruments can be exposed to the dusty conditions like observed on the Martian surface. Physical properties of analogue dust can be studied with a variety of techniques.

A third environmental chamber can be used for studying other properties of the Martian surface. The atmosphere and temperature can be controlled and monitored using a rest gas analyzer. A variety of coloured diodes and an ultra violet lamp can simulate the hard solar radiation, which penetrates the thin Martian atmosphere. Chemical and mineralogical processes can be studied, for example oxidation of Iron II compounds. Transport of heat and water vapour can be measured using modified sensors.

Objectives
By developing better analogues and simulations of the Martian surface it is hoped to improve our understanding of the physical processes at work. This has been shown to be vital in interpreting observations made on Mars as well as pioneering the next generation of experiments to be flown. Specific research projects underway are:

Electrical Dust Charging (discharging)

Magnetic Properties Experiments (past and present)

Dust Adhesion/Cohesion

These are not just of scientific interest, but can be crucial for securing the safety and performance of instrumentation Mars´surface, where the dust is also a dangerous environmental factor.

Beagle 2 materials testing from wind tunnel

Dust loading at the surface affects water transport and therefore the possibility of life. Evidence for recent flow of liquid water (Mars Express, Mars Global Surveyor and Mars Reconnaissance Orbiter) has prompted speculation as to the possibility of stable liquid water close to the surface of Mars. In fact at temperatures and pressures common on Mars the presence of liquid water can be stable given high humidity. Deposited dust makes water diffusion extremely slow and can therefore act as a barrier to escaping humidity.