Some satellites are powered by small nuclear reactors. Unlike earth-bound reactors, those in space are not shielded, because their radiation is thought to be harmlessly emitted in space. When one of these reactors passes near a satellite which is searching for naturally occurring gamma rays, however, its radiation is not harmless. Satellites record the gamma rays emitted by other satellites, and often miss entirely the naturally occurring gamma ray bursts which they are sent to track down.
Between 1961 and 1977 the USA launched 23 satellites with nuclear reactors in them. Four of them (17%) in into problems, including one that disintegrated on launch, tripling the amount of plutonium 238 in the Earth's environment. The former Soviet Union has launched 39 nuclear reactors on orbiting satellites since 1965, of which 6 (15%) have malfunctioned.
The Encyclopedia of World Problems and Human Potential is a collaboration between UIA and Mankind 2000, started in 1972. It is the result of an ambitious effort to collect and present information on the problems with which humanity is confronted, as well as the challenges such problems pose to concept formation, values and development strategies. Problems included are those identified in international periodicals but especially in the documents of some 60,000 international non-profit organizations, profiled in the Yearbook of International Organizations.
The Encyclopedia includes problems which such groups choose to perceive and act upon, whether or not their existence is denied by others claiming greater expertise. Indeed such claims and counter-claims figure in many of the problem descriptions in order to reflect the often paralyzing dynamics of international debate. In the light of the interdependence demonstrated among world problems in every sector, emphasis is placed on the need for approaches which are sufficiently complex to encompass the factions, conflicts and rival worldviews that undermine collective initiative towards a promising future.
Non-profit, apolitical, independent, and non-governmental in nature, the UIA has been a pioneer in the research, monitoring and provision of information on international organizations, international associations and their global challenges since 1907.