How are the numbers of orbital debris determined?
Large orbital debris (> 10 cm) are tracked routinely by the U.S. Space Surveillance Network. Objects as small as 3 mm can be detected by ground-based radars, providing a basis for a statistical estimate of their numbers. Assessments of the population of orbital debris smaller than 1 mm can be made by examining impact features on the surfaces of returned spacecraft, although this has been limited to spacecraft operating in altitudes below 600 km.
Large orbital debris (> 10 cm) are tracked routinely by the U.S. Space Surveillance Network. Objects as small as 3 mm can be detected by ground-based radars, providing a basis for a statistical estimate of their numbers. Assessments of the population of orbital debris smaller than 1 mm can be made by examining impact features on the surfaces of returned spacecraft, although this has been limited to spacecraft operating in altitudes below 600 km. 5).
