Dependence between volume filling factor and compressive pressure for dust aggregate, dust, and water-ice layers measured inthe laboratory (SC15: Schräpler et al. 2015; GU09: Güttler et al. 2009; LO16: Lorek et al. 2016). The experimental results for dust and ice layers have been extrapolated for lower volume filling factors (dashed lines). The derived compression range for the surface contacts of Philae are depicted by the vertical blue area. Measurements from Kofman et al. (2015; K), Pätzold et al. (2016; F), and Fulle et al. (2016; P) have been used to determine the possible range for the volume filling factor.