ABSTRACT
Soon after the beginning of the space age, satellites began to collect information about activities on Earth. This information from the unique vantage point of space has become prominent in enhancing effective deployment and management of military, intelligence, telecommunications, and scientific resources. This chapter focuses on one of these types of information, that from Earth observing satellites. The United States and some 30 other countries own and operate, unilaterally or cooperatively, about 78 civilian Earth observing spacecraft carrying 125 instruments. 1 The estimated total cost of investment in these systems is between $50 billion and $80 billion. 2 The spacecraft serve both research and management objectives by measuring and monitoring land use, air quality, freshwater supplies, the health of oceans, renewable energy resources, seismic conditions and related geology, natural events such as volcanic eruptions and weather extremes, and a wide range of additional variables comprising Earth’s climate and global carbon cycles. Additional and complementary Earth observations are collected by instruments on aircraft, on the ground, and at sea. National security observing networks also gather data on natural and environmental resources for defense deployment and operations, and, in some cases, to support civilian environmental and disaster response requirements.
