NASA's strategic goal in Earth science is motivated by the fundamental question: "How is the Earth
changing and what are the consequences for life on Earth?" NASA's mission in Earth science, as
mandated by the Space Act, is to "... conduct aeronautical and space activities so as to contribute
materially to ...the expansion of human knowledge of the Earth and of phenomena in the atmosphere and
space". Therefore NASA's role is unique and highly complements those of other U.S. Federal agencies
(such as the National Oceanic and Atmospheric Administration, National Science Foundation, U.S.
Geological Survey, and Environmental Protection Agency) by continually advancing Earth system science
from space, creating new remote sensing capabilities, and enhancing the operational capabilities of other
agencies and collaborating with them to advance national Earth science goals. Continuous global
observations of variability and change are required to reveal natural variability and the forces involved, the
nature of the underlying processes and how these are coupled within the Earth system. NASA's Earth
Science Division (ESD) provides these observations through its orbital and suborbital Flight Programs. In
the decade 2007-2016, ESD will develop and demonstrate new sensors and interacting constellations of
satellites to address critical science questions and enable advances in operational capabilities in response to
the National Research Council's Decadal Survey of Earth Science and Applications.