The CoPhyLab (Cometary Physics Laboratory) project is designed to study the
physics of comets through a series of earth-based experiments. For these
experiments, a dust analogue was created with physical properties comparable to
those of the non-volatile dust found on comets. This "CoPhyLab dust" is planned
to be mixed with water and CO2 ice and placed under cometary conditions in
vacuum chambers to study the physical processes taking place on the nuclei of
comets. In order to develop this dust analogue, we mixed two components
representative for the non-volatile materials present in cometary nuclei. We
chose silica dust as representative for the mineral phase and charcoal for the
organic phase, which also acts as a darkening agent. In this paper, we provide
an overview of known cometary analogues before presenting measurements of eight
physical properties of different mixtures of the two materials and a comparison
of these measurements with known cometary values. The physical properties of
interest are: particle size, density, gas permeability, spectrophotometry,
mechanical, thermal and electrical properties. We found that the analogue dust
that matches the highest number of physical properties of cometary materials
consists of a mixture of either 60\%/40\% or 70\%/30\% of silica dust/charcoal
by mass. These best-fit dust analogue will be used in future CoPhyLab
experiments
