SMAP: Tracking Earth's hidden water
Launch:
Status: Active
NASA's Soil Moisture Active Passive (SMAP) mission measures how much water is stored in Earth's surface soil from space. This moisture plays a key role in helping trees, plants and crops grow and supporting healthy ecosystems.
The satellite collects data continuously and revisits each location on Earth every 2 to 3 days, allowing scientists to monitor changes caused by storms, seasons, and long-term climate variations. Its radiometer instrument can measure moisture in the top 5 cm of soil, even through clouds and moderate vegetation, both day and night.
SMAP's measurements are used to create global maps that help researchers better understand how water, energy, and carbon cycles are connected and how they interact. These observations are especially useful for agriculture, weather forecasting, and environmental monitoring.
SMAP can also observe sea surface salinity, an important factor in understanding ocean circulation and water cycles. The satellite's data is often combined with observations from the European Space Agency's Soil Moisture and Ocean Salinity mission to develop enhanced scientific products.
Artist's conception of SMAP gathering data from orbit. (Credit: NASA)
Canada's role in the mission
Canada supports the SMAP mission through its long-standing collaboration with NASA and international partners. Canadian scientists have contributed for over two decades to advance satellite soil moisture observations and applications.
In collaboration with Environment and Climate Change Canada and Agriculture and Agri-Food Canada, researchers from five Canadian universities participated in the scientific validation of this mission:
- Institut national de la recherche scientifique
- Université de Sherbrooke
- University of Guelph
- University of Manitoba
- University of Toronto
Their work consisted in comparing coordinated observations that were collected on the ground, from aircraft, and from space. The results were used to assess the accuracy of SMAP measurements across a wide range of soils, land cover types, topographic settings, and atmospheric conditions. Such validation is particularly important in Canada, where vast and diverse landscapes change significantly from season to season.
Benefits for Canadians
The Canadian Space Agency supports the development of scientific applications that use SMAP data, through grants to universities, including initiatives such as Research Opportunities in Space Science. These applications contribute to environmental monitoring and forecasting, including droughts, wildfires, floods, crop conditions, forest productivity, and climate change impacts.
This information helps Canadian scientists and decision-makers reduce damage to infrastructure, better manage natural resources, and protect ecosystems and communities across Canada, particularly in the Arctic.
It also supports key Canadian economic sectors, such as agriculture and forestry, by improving their resilience and productivity in a changing environment.
In agriculture, SMAP data helps by:
- monitoring moisture levels in the top layer of soil where crops grow
- tracking seasonal soil freeze-thaw conditions
- providing early indicators of conditions that may favour pest and disease outbreaks
- supporting more informed decisions related to irrigation and crop management
In forestry, SMAP data helps by:
- monitoring soil moisture conditions that affect forest health, growth, and productivity
- supporting wildfire forecasting by detecting dry conditions
- tracking seasonal freeze-thaw cycles and their effects on forest ecosystems over time
SMAP's antenna is fully unfurled during a ground test. (Credit: NASA)
This long-exposure photograph shows a Delta II rocket carrying the SMAP satellite during its launch from Space Launch Complex 2 at Vandenberg Air Force Base in . (Credit: NASA/Bill Ingalls)