September 2004 saw release of the Strategic Plan for the US Integrated Earth Observation System. The plan states that Earth Observations (EO) gained through sensors on orbiting systems constitute critical input for resolving issues related to protecting the global environment, including global warming and dust storms, and for reducing loss of life and property caused by nature or/and human-induced disaster. In the meantime, new EO strategies have emerged aimed at further improving our ability to monitor, understand and predict changes in weather, climate, oceans, atmosphere, water, land, geodynamics, natural resources, ecosystems, and natural and human-induced hazards. At about the same time, the author and co-workers on the Strategic Plan presented the architecture and concept of future intelligent earth observing satellites (FIEOS); see the International Journal of Remote Sensing; 25; 14; 2667-2685).

FIEOS consists of multiple orbiting satellites organised within an architecture enabling close co-operation and data exchange. Onboard the satellites are not only EO sensors, as in conventional architectures, but also data processors and communication links. The dynamic integration of these diverse components allows for observation of the Earth's environment in an adaptable and seamless manner for a variety of purposes. Each satellite independently collects, analyses and interprets data using its own sensors and onboard processors. Data indicating changes having occurred in the Earth's environment is first processed and then transmitted to ground users via ground stations or geostationary satellites.

When change such as a forest fire has been detected, the satellite sensing system is rotated into position and its coverage area altered by adjusting its system parameters to bring the event into focus. Meanwhile the sensing-satellite instructs member-satellites in its group to adjust their sensors to simultaneously acquire the event, resulting in multi-angle, multi-sensor, multi-resolution and multispectral observations. The data collected is transmitted to a geostationary satellite, where the diverse datasets are merged and analysed. Priority levels are assigned according to the changes detected. Following progressive compression, data is available for transmission to other geostationary satellites, and the communication links between them provide the capability for worldwide coverage and real-time processing.

Meanwhile the geostationary satellite further processes the data to develop value-added products, such as predictions of fire extent, weather influence on the fire, and the pollution it causes, and then transmits these products to users. FIEOS will perform much of the event detection and response processing that is presently performed by ground-based systems. Of course, many technical challenges are involved in building an EO system which is intelligent, comprehensive, integrated and sustained.