This program focuses on pollution in space and the how it can be managed and controlled. In the most general sense, the term space pollution includes both the natural micro meteoroid and man-made orbital debris components of the space environment’ however, as pollution is generally considered to only man-made orbital debris.Orbital debris poses a threat to both manned and unmanned spacecraft range from surface abrasion due to repeated small-particle impact to a catastrophic fragmentation due to a collision with a large object.
Debris is typically divided into three size ranges, based on the damage it may cause: less than 1 centimeter(cm), 1 to 10 cm, and larger than 10 cm. Objects less than 1 cm may be shielded against, but they still have the potential to damage most satellites. Debris in the 1 to 10 cm range is not shielded against, cannot easily be observed and could destroy a satellite. Finally, collisions with objects larger than 10 cm can break up a satellite. Of these size ranges,only objects 10 cm and regularly tracked and cataloged by surveillance networks.
Remediation takes two courses: protection and mitigation. Protection seeks to shield spacecraft and utilize intelligent design practices to minimize the effects of debris impact. Mitigation attempts to prevent debris from being created. Active mitigation techniques include collision avoidance between tracked and maneuverable objects and the intentional reentry of objects over the oceans. Passive techniques include venting residual fuels or pressurized vessels aboard rockets and spacecraft, retaining operational debris and placing spacecraft into disposal orbits at the end of a mission. Space salvage or retrieval, while an option is currently too expensive to employ on a regular basis.
Remediation strategies have resulted in a decline in the rate of debris growth in the 1990s although the overall population continues to grow. Continued work is necessary, however, to reduce the orbital debris hazard for future generations and continue the safe, economical utilization of space.