# Small Solar System Bodies as granular media

## TL;DR

This paper explores the physical properties and structure of small Solar System bodies, emphasizing their granular, rubble-pile nature, which is crucial for understanding their origin, evolution, and potential for space missions and planetary defense.

## Contribution

It provides a comprehensive analysis of the granular media characteristics of small bodies, integrating recent mission data and theoretical models to enhance understanding of their mechanical behavior.

## Key findings

- Small bodies are often rubble piles with low internal cohesion.
- Surface and bulk properties vary widely among small bodies.
- Understanding granular behavior is key for future exploration and mitigation.

## Abstract

Asteroids and other Small Solar System Bodies (SSSBs) are of high general and scientific interest in many aspects. The origin, formation, and evolution of our Solar System (and other planetary systems) can be better understood by analysing the constitution and physical properties of small bodies in the Solar System. Currently, two space missions (Hayabusa2, OSIRIS-REx) have recently arrived at their respective targets and will bring a sample of the asteroids back to Earth. Other small body missions have also been selected by, or proposed to, space agencies. The threat posed to our planet by near-Earth objects (NEOs) is also considered at the international level, and this has prompted dedicated research on possible mitigation techniques. The DART mission, for example, will test the kinetic impact technique. Even ideas for industrial exploitation have risen during the last years. Lastly, the origin of water and life on Earth appears to be connected to asteroids. Hence, future space mission projects will undoubtedly target some asteroids or other SSSBs. In all these cases and research topics, specific knowledge of the structure and mechanical behaviour of the surface as well as the bulk of those celestial bodies is crucial. In contrast to large telluric planets and dwarf planets, a large proportion of such small bodies is believed to consist of gravitational aggregates ('rubble piles') with no -- or low -- internal cohesion, with varying macro-porosity and surface properties (from smooth regolith covered terrain, to very rough collection of boulders), and varying topography (craters, depressions, ridges) [...].