The curation of extraterrestrial samples (astromaterials) obtained by sample-return missions takes place at facilities specially designed to preserve both the sample integrity and protect the Earth. Astromaterials are classified as either non-restricted or restricted, depending on the nature of the Solar System body. Non-restricted samples include the Moon, asteroids, comets, solar particles and space dust. Restricted bodies include planets or moons suspected to have either past or present habitable environments to microscopic life, and therefore must be treated as extremely biohazardous. Source: Wikipedia (en)