  Understanding the properties of particle aggregation and resulting aggregates
under microgravity conditions leads to better insights on the formation of the
early Solar System planetesimals. Simulating such conditions is the main
objective of Interactions in Cosmic and Atmospheric Particle System (ICAPS), a
multi-users facility currently under phase B at ESA for the International Space
Station. First results of light scattering simulations by core-mantle
aggregates of grains with organics and icy mantles are presented to show the
evolution of polarization with aggregation. The Light Scattering Unit is both a
polarization diagnostic tool for ICAPS, and an experiment that will allow the
interpretation of the available light scattering dust observations in terms of
physical properties of the scattering media. This presentation updates the
current approach of the calibration procedures and the innovative experimental
setup (providing a phase angle exploration from about 2{\deg} to 175{\deg}
together with a wavelength exploration from 0.4 to 0.8 micrometer). We also
assess the possibility for the determination of the entire Stokes vector of the
light scattered by the aggregates.
