Measures to reduce the growth or decrease the space debris population

The increasing threat posed by space debris to active satellites urges the space community to react. Numerous authors demonstrated that without very e ffective measures, space pollution will become a major problem within the c oming decades. To improve the situation, four ways can be followed : collisions can be avoided by prediction and maneuvers; this measure is unfo rtunately limited to catalogued objects, i.e. less than 10% of the dangerou s population satellites can be protected against the effects of collisions; shields can be added, satellite layout can be optimized or operational constraints can be applied, all measures leading to severe operational impact for the satel lite (mass, complexity, cost,...) removal of existing space debris can be considered; several removal systems have been proposed, acting from ground or from space, but they are either very costly or far to advanced technologically to be baselined seriously a drastic reduction of the number of debris generated in the future can be aimed at; most of the space faring agencies now propose "space debris mitig ation standards", applicable to any new space project under their responsib ility. The paper focusses mainly on this last measure, describing the highlights o f the CNES standard, given as an example. Last, the paper gives a brief ove rview of the current efforts at international level to come out with widely agreed rules. (C) 2000 Bonnal-Alby-CNES. Published by Elsevier Science Ltd .