Digital system design in the presence of single event upsets

The authors consider the effects of single event upsets (SEUs) on digital systems, and show techniques for designing reliable systems with current levels of SEU protection. Three main systems are discussed: main memory, logic, and cache memory. A design for the main and cache memory subsystems that are SEU protected is also described. With SEU defined in bit days p, and using single error correction, it is shown that for all subsystems considered, an effective upset rate which is proportional to the product of p² and the time between corrections, or scrub time, can be obtained. Data for memory chip size and performance derived from the gallium-arsenide (GaAs) pilot lines funded by the Defense Advanced Research Projects Agency (DARPA) throughout the 1980s are used     

Space technology in the third world : Commercialization and the spread of ballistic missiles

The recent enthusiastic initiatives in the USA to commercialize space activities are also likely to facilitate and accelerate Third World ventures in space. This article outlines the history of Third World space activities and points to the danger that these nations will use satellite launch technology for military applications. Competitive economic and political pressures are aiding the migration of older missile technology to Third World Nations. The author argues for the establishment of an International Missile Technology Regime, which would limit the transfer of space launch technology to nations which are in full compliance with the 1968 Nuclear Non-Proliferation Treaty.