What are meteoroids and orbital debris?
Meteoroids are natural particles in orbit about the sun. Their size is considerably smaller than an asteroid and considerably larger than an atom or molecule. Orbital debris is man-made material induced by spacecraft that can be as large as spent rocket motors and as small as the dust particles ejected from the nozzles of maneuvering thrusters. Currently, over 7000 large objects (>10 cm) are being tracked as orbital debris. The graphic shows the number of catalogued space objects in orbit as of 27 September 1991. Meteroids and Orbital Debris Sources? Meteoroids are natural particles that are not individually tracked and catalogued. The vast majority of meteoroids are cometary in nature but some have asteroidal origin as well. Orbiting spacecraft debris is the remains from space missions. The worst particulate pollution for orbital debris occurs when a rocket or spacecraft accidentally explodes at high altitudes. The graphic shows the sources of catalogued debris population. Meteoroids
