Since 1957, more than 4900 space launches have led to an orbital population today of more than 23 000 trackable objects with sizes larger than 10 cm. Some 1000 of these are operational satellites. The remaining 94% are space debris – objects that no longer serve any useful purpose.
About 64% of the routinely tracked objects are fragments from some 250 breakups, mainly explosions and collisions of satellites or rocket bodies.
In addition, an estimated 670 000 objects larger than 1 cm and 170 million objects larger than 1 mm are expected to be in orbit.
Owing to relative orbital velocities of up 56 000 km/hr, centimeter sized debris can seriously damage or disable an operational spacecraft. Collisions with objects larger than 10 cm will lead to catastrophic break-ups, releasing hazardous debris clouds of which some fragments can cause further catastrophic collisions that may lead to an unstable debris environment in some orbit regions – the ‘Kessler syndrome’.
Space debris mitigation measures, if properly implemented by spacecraft designers and mission operators, can curtail the growth rate of the debris population. Active debris removal, however, has been shown to be necessary to reverse the debris increase.
Space debris has recently been attracting increasing attention not only due to the growing recognition of the long-term need to protect the commercially valuable low-Earth and geosynchronous orbital zones, but also due to the direct threat that existing debris poses to current and future missions.
While commercial and scientific uses of space have expanded across a wide range of activities, including telecommunications, weather, navigation, Earth observation and science, space debris has continued to accumulate, endangering space operations.
To improve our understanding of the space debris environment, assess related risks, mitigate its growth, and control its stability, a multitude of technical disciplines is required. Most of these will be addressed in the course of this conference by recognised experts in their fields.