Meteoroid

Meteoroids are between 100 µm and 10m in diameter and move at velocities of 20–27 kms^-1; micro-meteoroids are <100 µm and are largely made of cosmic dust. While the concentrations of both are low, their velocity is such that they pose significant problems when they strike a space vehicle such as a satellite; even the impact of micro-meteorites will have an effect like sand blasting over a period of time.