Spacecraft must be analyzed for their ability to survive hypervelocity impacts (HVI) by orbital debris, as the collision of a space vehicle with even a millimeter-sized object traveling at a typical orbital speed (7 km/s and higher) can be detrimental for both the spacecraft and the orbital environment. Due to the high cost of the physical HVI experiments, numerical modeling plays a significant role in conducting such analyses. With the extensive use of advanced lightweight materials with complex mesostructure in space engineering, it is important to find a rational way of representing them in numerical simulations. This study reports the results of numerical modeling of two distinct types of lightweight materials often employed in space structures, namely open-cell foams and fiber-reinforced composites. For foams, explicit representation of their complex mesoscopic architecture was achieved by filling the STL exteriors (generated using X-ray computed tomography) with SPH particles. For laminated composites, ply-wise representation was obtained using finite elements that could locally and adaptively transform to SPH particles when the elements become highly distorted and inefficient. Results of HVI simulations involving foams and composites were compared with available experimental data. The advantages and limitations of the modeling techniques are discussed.