Theoretical and experimental investigations of light scattering by heterogeneous non-spherical cosmic dust grains Dust is ubiquitous in the Universe. It can be found in the Solar system, in the interstellar medium in our and other galaxies, but also in distant quasars. Despite the fact that only 1 per cent of interstellar material is in the form of dust, the very efficient absorption of radiation by dust particles causes it to play an important role in the energy balance of the interstellar medium. Since it provides a surface, it is also important for the chemistry of the interstellar medium and of star forming regions: indeed, dust is a key ingredient in the formation process of new generations of stars and planets. It is therefore essential to constrain the properties of interstellar dust, by means of the study of the interaction of radiation with dust. The purpose of the project is to study this interaction of radiation with small dust particles in astrophysical environments. We will use three main approaches: (i) the development of realistic numerical models to treat scattering of light by small dust particles (tasks 1, 3 and 4); (ii) the experimental verification of these numerical models by laboratory measurements of cosmic dust analogues (tasks 2 and 3); (iii) the application of these numerical techniques and laboratory measurements for the interpretation of astronomical observations of dust (task 5). The tasks refer to those given in the original proposal.