"The Earth Resources Technology Satellite, ERTS-1 (recently renamed LANDSAT-1), and its successor, LANDSAT-2, are providing the world with a revolutionary form of electro-optical overhead imagery at very low cost to the consumer. ERTS products are freely available for purchase from the United States, and a growing number of countries are building their own ground receiving stations. ERTS data could be a source of strategic intelligence for countries that do not have access to overhead reconnaissance systems but do have strategic missile-targeting and other military requirements. Because of the growing usage of ERTS data and de-centralization of dissemination centers, the difficult of detecting foreign military intelligence use of that data is increasing rapidly. This study reveals little evidence that foreign countries are exploiting the military and strategic intelligence potential of purchased ERTS data; but the Peoples Republic of China, which has shown interest in ERTS data and has made a considerable effort to obtain geodetic information and maps covering the Soviet Union and other areas, appears to be a possible user of ERTS data for such applications. An assessment of standard ERTS multi-spectral film coverage of selected Soviet areas indicates that the Chinese could now use it to identify and target large cities, airports, port facilities and transportation routes. ERTS digital images and data, supplemented by collateral information, could be used to map and target even smaller features, such as the larger Soviet SAM [surface-to-air missile] sites and soft ICBM [intercontinental ballistic missile] sites."
National Security Archive at George Washington University: http://www.gwu.edu/~nsarchiv/