Such an impact can have serious consequences, depending on the point of impact and the size of the body. Due to their great speed, the space debris are able to penetrate sheets of metal, plastic or glass and to cause big damage to instruments and vehicle systems. Our knowledge about the consequences of such impacts is mainly derived through studies of similar events in observed in space missions like the SkyLab and the Mir station. Special studies have been conducted in order to estimate the potential hazards of space debris to the International Space Station, which will start to be assembled in space by the end of 1998. Due to the great importance of the Station, the presence of many people on board and the long life-time of the mission, several parts of the Station have been specially designed and built in order to withstand the hazardous environment.
Conclusions There is rather little margin for avoiding the threats posed by space debris.
With regard to meteoroids, we can only minimise the potential danger by designing carefully the space missions. With regard to orbital debris, we must try to produce no new debris and to monitor the existing ones. The last few years several international meetings and discussions have been conducted and a few mitigation measures have been proposed, in order to reduce the rate of increase of orbital debris. 2. movement of useless objects and of vehicles that concluded their mission to orbits that will gradually brought them back to Earth. If this is impossible or too dangerous, movement of these objects to orbits in areas of space that are not normally used for space missions.