SpaceX has launched the Surface Water and Ocean Topography (SWOT) radar satellite for NASA on December 16, 2022. Data from SWOT will be used to study how oceans absorb atmospheric heat and carbon dioxide.
In a move that rapidly became standard procedure for SpaceX, it landed the first stage booster of the Falcon 9 rocket and can refurbish it for another mission. This move helps SpaceX keep costs down as opposed to simply discarding rocket stages in the ocean after each launch – something that SWOT’s backers might appreciate because it reduces space launch-related litter in the ocean.
Current estimates show that oceans absorb 90% of the heat trapped in the atmosphere by greenhouse gases. This has helped keep temperatures under control despite the amount of greenhouse gases pumped into the atmosphere by industrial activity.
Scientists have expressed concern about a possible “tipping point” at which oceans would begin to release the heat trapped within them rather than absorbing heat. SWOT will help them make more accurate predictions about where that tipping point is.
SWOT is capable of conducting radar sweeps of most of Earth’s surface twice every 21 days. The data produced will help make ocean circulation models more accurate. It will also improve the accuracy of weather forecasts and assist with managing the water supply in regions impacted by drought. SWOT can also measure small differences in surface elevations where smaller currents and eddies exist. Scientists believe that a lot of the oceans’ heat absorption happens in these small currents and eddies.
Combined with data from other satellites, data from SWOT can also assist studies of the impact of changing ocean levels on coastal areas.
SWOT can also take measurements of more than a million lakes and reservoirs on Earth’s surface. It will also take measurements of rivers that are wider than 100 meters (330 feet). These measurements will provide data to scientists studying seasonal fluctuations of lake and river levels and the impact of harsh weather events on lakes and rivers.
Unlike most satellites, SWOT is capable of taking measurements through cloud cover and map them in two dimensions. Previous satellites could only take measurements at specific points and map them in a single dimension.
The SWOT team has plans for a three-year mission for the satellite. It will send down the first research data within months.
The NASA-funded Jet Propulsion Laboratory (JPL) built most of the components for SWOT. Canada and Britain also contributed to the SWOT mission. France’s space agency, CNES, helped track SWOT’s deployment and reported receiving the expected first signals from the satellite, indicating that it is fully operational.
SWOT was one of 15 NASA missions listed as priorities by the National Research Council when mission planners started working on it twenty years ago. The National Research Council regularly updates its priorities, which are often consistent with the U.S. government’s current science-related policies.