The Soil Moisture Active and Passive (SMAP) mission is one of four missions recommended by the U.S. National Research Council Committee on Earth Science and Applications from Space for launch in the 2010-2013 time frame ("Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond," National Academies Press, 2007).

SMAP will use a combined radiometer and high-resolution radar to measure surface soil moisture and freeze-thaw state, providing new opportunities for scientific advances and societal benefits. Direct measurements of soil moisture and freeze/thaw state will aid understanding of regional and global water cycles, ecosystem productivity and the processes that link the water, energy, and carbon cycles. Soil moisture and freeze/thaw state information provided by SMAP at high resolution will enable improvements to weather and climate forecasts, flood prediction and drought monitoring, and measurement of net CO2 uptake in forested regions.