Paperback. This publication contains 36 papers taken from three symposia of COSPAR Scientific Commission B, which took place during the Thirty-first COSPAR Scientific Assembly, held in Birmingham, UK, during July 1996. The major areas covered by the symposia and which form this volume are as follows: the particulate space environment, problems in comparative planetology, and laboratory investigations relevant to planetology. Papers on the particulate space environment reflect advances in evaluation of the space environment, the deeper understanding of hypervelocity impact phenomena, and hold interest for the understanding of the natural environment and space debris. Papers on problems in comparative planetology investigate differences in impact melting on the surfaces of different planets, the geology of Alba Petra on Mars and attempts to interpret the geology of that region in terms of the geology of corona structures found on Venus. Papers concerning la

"This volume contains a sizable suite of contributions dealing with regional impact records (Australia, Sweden), impact craters and impactites, early Archean impacts and geophysical characteristics of impact structures, shock metamorphic investigations, post-impact hydrothermalism, and structural geology and morphometry of impact structures - on Earth and Mars"--

The thesis presents a tool to create rubble pile asteroid simulants for use in numerical impact experiments, and provides evidence that the asteroid disruption threshold and the resultant fragment size distribution are sensitive to the distribution of internal voids. This thesis represents an important step towards a deeper understanding of fragmentation processes in the asteroid belt, and provides a tool to infer the interior structure of rubble pile asteroids. Most small asteroids are 'rubble piles' – re-accumulated fragments of debris from earlier disruptive collisions. The study of fragmentation processes for rubble pile asteroids plays an essential part in understanding their collisional evolution. An important unanswered question is “what is the distribution of void space inside rubble pile asteroids?” As a result from this thesis, numerical impact experiments can now be used to link surface features to the internal structure and therefore help to answer this question. Applying this model to asteroid Šteins, which was imaged from close range by the Rosetta spacecraft, a large hill-like structure is shown to be most likely primordial, while a catena of pits can be interpreted as evidence for the existence of fracturing of pre-existing internal voids.