Spying From Above: How the Atmosphere Helped Shape Our Modern Surveillance Systems.

The energy required to boost a satellite, particularly a large photoreconnaissance or other ISR satellite, through the atmosphere into space is immense, requiring large rockets loaded with hundreds of thousands of pounds of high energy, potentially explosive fuel. For the United States, much the science of boosting satellites into orbit began with Operation Paperclip, where agents of the United States secreted leaders of Nazi Germany's ballistic missile program into America. The satellite orbited the earth 17 times, including eight passes over the Soviet Union, allowing coverage of 1.5 million square miles of the country, far more than all coverage of the U-2's overflights of the U.S.S.R. combined. The Soviets unknowingly provided a continuous feed of weather information that the NRO used in real time to turn on reconnaissance satellite cameras over cloud free targets and then turn them off over cloud-covered areas, saving precious film. [Extracted from the article]