Micrometeoroids are natural dust particles with masses between 10
−21
and 10
−9
kg (0.01–100 μm). In contrast to space debris, their sources are bodies in the solar system like comets, asteroids or planetary environments.
Although comets are the most obvious source of interplanetary dust in the inner solar system, there exist a variety of dusty phenomena and dust sources.
An recent summary about interplanetary dust was given by gruen 2001. Our current knowledge is based on remote sensing observations (light scattering, thermal emissions),
in‐situ
dust experiments, (Pioneer, Giotto, Helios, Heos, Nozomi, Gorid, Galileo, Cassini, Ulysses, Stardust, New Horizon), crater studies of moon rocks or of planetary moon surfaces, meteor radar studies and laboratory sample analysis. (dust extracted from polar ices, dust collected in the stratosphere, dust returned by Stardust, dust and space debris impact residues of returned satellite parts).
The following sections describe the measurement techniques of micrometeoroids, the properties of interplanetary dust (mass flux, dynamics, or composition) and the dust sources like comets, asteroids, or planetary environments. Two later sections give examples of laboratory simulation facilities. Finally, hazards related to hyper‐velocity micrometeoroid impacts are discussed.