Earth remote sensing technologies in the twenty-first century

An Earth System Model of increasing capability and predictive power will depend on ever more sophisticated observing systems. These observing systems will require increased resolution in the spatial, spectral, radiometric, and temporal domains. There is a need for improvement of individual system capabilities and for the deployment of large numbers of sensors. Many new technologies will be required to accomplish this. Projecting decades into the future is difficult; however, because fundamental physical limits provide constraints on future progress, it is possible to outline the general form of the future remote sensing systems and the technologies they will rely on. Several trends are expected to continue far into the future: miniaturization and integration of electronics, increases in computational power, progress in large apertures, increases in transmitter power for active systems, miniaturization of optics, and increases in frequency tunability and flexibility. Ultimately, the size of an observing platform will be dictated solely by the physics of its parts. These technology challenges for future global Earth observation can best be met through the combined efforts of the international community.