NASA Administrator Charles Bolden, left, and Centre National d'Études Spatiales (CNES) President Jean-Yves Le Gall sign an agreement to move from feasibility studies to implementation of the Surface Water and Ocean Topography (SWOT) mission, Friday, May 2, 2014 at NASA Headquarters in Washington.
NASA-CNES Move Forward with Global Water and Ocean Surface Mission
NASA and the French space agency Centre National d'Études Spatiales (CNES) have agreed to jointly build, launch, and operate a spacecraft to conduct the first-ever global survey of Earth's surface water and to map ocean surface height with unprecedented detail.
NASA Administrator Charles Bolden and CNES President Jean-Yves Le Gall signed an agreement Friday at NASA Headquarters in Washington to move from feasibility studies to implementation of the Surface Water and Ocean Topography (SWOT) mission. The two agencies began initial joint studies on the mission in 2009 and plan to complete preliminary design activities in 2016, with launch planned in 2020.
"With this mission, NASA builds on a legacy of Earth science research and our strong relationship with CNES to develop new ways to observe and understand our changing climate and water resources," said NASA Administrator Charles Bolden. "The knowledge we'll gain from SWOT will help decision makers better analyze, anticipate, and act to influence events that will affect us and future generations."
SWOT is one of the NASA missions recommended in the National Research Council's 2007 decadal survey of Earth science priorities. The satellite will survey 90 percent of the globe, studying Earth's lakes, rivers, reservoirs and ocean to aid in freshwater management around the world and improve ocean circulation models and weather and climate predictions.
This new agreement covers the entire life cycle of the mission, from spacecraft design and construction through launch, science operations, and eventual decommissioning. NASA will provide the SWOT payload module, the Ka-band Radar Interferometer (KaRIn) instrument, the Microwave Radiometer (MR) with its antenna, a laser retroreflector array, a GPS receiver payload, ground support, and launch services.
CNES will provide the SWOT spacecraft bus, the KaRIn instrument’s Radio Frequency Unit (RFU), the dual frequency Ku/C-band Nadir Altimeter, the Doppler Orbitography and Radiopositioning Integrated by Satellite (DORIS) receiver package, satellite command and control, and data processing infrastructure.
NASA and CNES began collaborating on missions to monitor ocean surface changes in the 1980s. From the TOPEX/Poseidon mission launched in 1992 to the Jason-1 mission launched in 2001 to the Jason-2/Ocean Surface Topography Mission launched in 2008, the collaboration has produced critical information on sea-level rise as well as El Niño causing world-wide impact.
The SWOT mission will use wide swath altimetry technology to produce high-resolution elevation measurements of the ocean surface and the surface of lakes, reservoirs, and wetlands. A more complete inventory of Earth's lakes and the changing amount of water they hold will yield improved assessments of how climate-induced changes can impact freshwater resources worldwide. Only 15 percent of lakes around the world are currently measured from space. SWOT will inventory a majority of medium to large lakes as well as the discharge volumes of rivers.
SWOT will be able to measure the ocean's surface with 10 times the resolution of current technologies. This will allow scientists to study small-scale features that are key components of how heat and carbon are exchanged between the ocean and atmosphere. The higher resolution of SWOT observations also will enable researchers to compute the velocity and energy of ocean circulation. A better understanding of small-scale ocean currents and eddies is also important to impacts on coastal regions such as navigation, erosion and dispersing pollutants.
Testing, Testing: Space-Bound US-European Water Mission Passes Finals
A rigorous testing program is the best way to ensure that every part of the Surface Water and Ocean Topography mission, down to the ball bearings, will work smoothly in orbit.
Before any NASA mission is launched, the spacecraft goes through weeks of harsh treatment. It’s strapped to a big table that shakes as hard as the pounding of a rocket launch. It’s bombarded with louder noise than a stadium rock concert. It’s frozen, baked, and irradiated in a vacuum chamber that simulates the extremes of space. The Surface Water and Ocean Topography mission (SWOT), a collaborative U.S.-French mission to monitor all the water on Earth’s surface, has passed these major tests. Now, except for a few final checks, SWOT is ready for its December launch.
Some of SWOT’s engineers at NASA’s Jet Propulsion Laboratory in Southern California have invested almost a decade in designing, building, and assembling this complex mission. Watching the instruments they’ve labored over go through the latest round of tests has been stressful, but the team has taken the process in stride. That’s because every part of SWOT, down to nuts and bolts, had been tested multiple times before the satellite entered the thermal vacuum chamber for the last time. The engineers say the earlier tests produced far more anxiety.
The solar panels on the Surface Water and Ocean Topography (SWOT) satellite unfold as part of a test in January 2022 at a Thales Alenia Space manufacturing facility near Cannes, France. The SWOT mission is being jointly led by NASA and the French space agency Centre National d'Études Spatiales (CNES), with contributions from the Canadian Space Agency and the United Kingdom Space Agency.
Many of SWOT's radar instruments were built at NASA's Jet Propulsion Laboratory in Southern California before being transported to France, where Thales Alenia is assembling the full satellite. Following a series of tests, SWOT will be transported to Vandenberg Space Force Base in Southern California for launch in November 2022. In orbit, SWOT will collect information of unprecedented detail on sea-level height, which will help scientists study the role of ocean currents in moderating climate change, as well as the elevations of fresh water bodies, which will enable researchers for the first time to take inventory of the planet's rivers, lakes, reservoirs, and other surface water.
JPL, which is managed for NASA by Caltech in Pasadena, California, leads the U.S. component of the mission. For the flight system payload, NASA is providing the KaRIn instrument, a GPS science receiver, a laser retroreflector, a two-beam microwave radiometer, and NASA instrument operations. CNES is providing the Doppler Orbitography and Radioposition Integrated by Satellite (DORIS) system, nadir altimeter, the KaRIn RF subsystem (with support from the UK Space Agency), the platform, and ground control segment. CSA is providing the KaRIn high-power transmitter assembly. NASA is providing the launch vehicle and associated launch services.
Phoebe Rhodes-Wickett, a mechatronics engineer at JPL, has spent a quarter of her life working on SWOT. She initially focused on a small component used to deploy the antennas on the spacecraft’s main instrument. “The first time I tested my mechanism, I was terrified,” she said. About as big as a box of tissues, the component was tested on a full-size shaker table. “It was just this little mechanism sitting by itself. The test is loud, and you can see the mechanism moving,” added Rhodes-Wickett. “We had a failure in our first round of testing. We had to redesign and retest the mechanism in a few months’ time to get it certified as spaceworthy.”
After passing that retest, the mechanism was connected to larger and larger systems that were finally integrated into the complete SWOT spacecraft. Every phase of spacecraft assembly creates new connections and presents another avenue for human error to creep in, so it ends with another round of tests. Rhodes-Wickett’s mechanism passed vibration testing three more times since that first experience. “Each test you pass is a relief,” she said, “but by the time you get to the third or fourth test, your stress level is much lower.”
The mechanism is part of SWOT’s new radar instrument, which is the first of its kind in space. The Ka-band Radar Interferometer, or KaRIn, has two radar antennas mounted on mechanical arms. Once SWOT is in orbit, the arms will unfold from opposite sides of the spacecraft and extend until the antennas are almost 33 feet (10 meters) apart. Just as the space between your eyes helps you to judge distance and depth better, the space between KaRIn’s two antennas helps the instrument reveal more details about Earth’s water. But if the process isn’t almost perfect – if the mechanical arms don’t extend fully or the antennas are misaligned by even a few thousandths of a degree – KaRIn can’t make the hoped-for measurements.
“It’s a unique part of a career at NASA that we’re always trying to build stuff that’s never been built before,” said JPL’s Eric Slimko, chief mechanical engineer on SWOT. That means every NASA payload starts with an unknown risk factor. Most missions gain some sense of the risk level by deploying prototype instruments on aircraft and in labs, but there’s still the (literally) sky-high additional challenge of adapting the technology to survive launch and work in space. “We don’t have the capability of eliminating all that risk by an analysis on a piece of paper,” he said. “We have to test it.” Even off-the-shelf parts are certified.
Designing tests that could prove the folding arm and antenna assembly will perform as well in orbit as they do on Earth was “very, very challenging,” Slimko said. “For one thing, we can’t turn off gravity. But we developed a verification program that, even though we cannot re-create the exact flight environment on the ground, we still have complete confidence that it will work in space.”
Carrying out the program required dozens of JPL engineers to spend weeks or months at the Thales Alenia Space facility in Toulouse, France, working with colleagues from the French space agency Centre Nationale d’Études Spatiales (CNES) to complete the series of tests as the spacecraft was assembled. The spacecraft includes hardware from not only CNES and NASA but also the United Kingdom and Canadian space agencies, with each team monitoring the performance of its own parts during testing.
Now almost all that remains is the ultimate test: the launch itself. The engineers are more than ready. “It’s fun to have a baby that you literally dreamed up, helped to grow, and now you’re walking it to the finish line,” Rhodes-Wickett said. “It’s really exciting to see something that you’ve poured so much time and effort into go on and make a difference in the world.”
More About the Mission
SWOT is being jointly developed by NASA and CNES, with contributions from the Canadian Space Agency and the United Kingdom Space Agency. JPL, which is managed for NASA by Caltech in Pasadena, California, leads the U.S. component of the project. For the flight system payload, NASA is providing the KaRIn instrument, a GPS science receiver, a laser retroreflector, a two-beam microwave radiometer, and NASA instrument operations. CNES is providing the Doppler Orbitography and Radioposition Integrated by Satellite (DORIS) system, the dual frequency Poseidon altimeter (developed by Thales Alenia Space), the KaRIn radio-frequency subsystem (together with Thales Alenia Space and with support from the UK Space Agency), the platform, and ground control segment. CSA is providing the KaRIn high-power transmitter assembly. NASA is providing the launch vehicle and associated launch services.
NASA Invites Media to Launch of Water-Monitoring Satellite
Media accreditation is now open for the upcoming launch of the Surface Water and Ocean Topography (SWOT) satellite, a pathfinder mission about Earth’s water that will use new technology to address climate change and its impact on our environment.
NASA and SpaceX are targeting no earlier than Monday, Dec. 5, for launch of the Earth-facing satellite on a SpaceX Falcon 9 rocket from Space Launch Complex-4 East at Vandenberg Space Force Base in California.
U.S. and international media interested in attending this launch must apply no later than 5 p.m. EDT on Thursday, Oct. 27. Media accreditation requests should be submitted at:
A copy of NASA’s media accreditation policy is available online. For questions about accreditation, please email: email@example.com. For other mission questions, please contact Kennedy’s newsroom: 321-867-2468.
Para obtener información sobre cobertura en español en el Centro Espacial Kennedy o si desea solicitar entrevistas en español, comuníquese con Antonia Jaramillo at: firstname.lastname@example.org or 321-501-8425.
SWOT is an international satellite mission led by NASA and the French space agency Centre National d’Études Spatiales (CNES) that will survey water on Earth’s surface, observe the fine details of ocean surface topography, and measure how water bodies change over time. The Canadian Space Agency and the UK Space Agency also have contributed to developing SWOT. NASA’s Launch Services Program at Kennedy is managing the launch.
Satellite to Study Earth’s Water Arrives at Launch Site
The international SWOT mission will view Earth’s ocean and surface water on land with unprecedented clarity.
The Surface Water and Ocean Topography (SWOT) satellite arrived at Vandenberg Space Force Base in California, where teams will begin final preparations for the spacecraft’s launch in December on a SpaceX Falcon 9 rocket from Space Launch Center-4 East.
SWOT is the first satellite mission that will observe nearly all water on Earth’s surface, measuring the height of water in the planet’s lakes, rivers, reservoirs, and the ocean. SWOT’s instruments will be able to resolve ocean features like currents and eddies less than 60 miles (100 kilometers) across, lakes and reservoirs larger than 15 acres (6 hectares), and rivers wider than 330 feet (100 meters) across.
NASA’s Jet Propulsion Laboratory in Southern California built the scientific payload. In June 2021, JPL shipped the payload to France, where a multinational team integrated the Ka-band Radar Interferometer (KaRIn) and other finely tuned instruments with the satellite bus.
On Oct. 16, SWOT arrived at Vandenburg from France aboard a U.S. Air Force C-5 Galaxy aircraft and moved to the Astrotech Space Operations facility to begin launch processing. In the coming weeks, SWOT will undergo many steps in preparation for liftoff. Teams must encapsulate the satellite in a protective payload fairing, mate it to the rocket, and transport it to the launch pad before it’s ready to rocket into space.
Once in orbit, SWOT will collect data from the ocean, helping researchers better understand how seawater absorbs atmospheric heat and carbon, a process that affects global temperatures and climate change. This data will also help researchers better understand coastal sea levels and, ultimately, how sea surface height will interact with a changing climate to affect things like storm surges.
SWOT will also provide the first comprehensive global survey of freshwater lakes, rivers, and reservoirs from space. The satellite will measure the height of the water in these water bodies, as well as their surface area, or extent. By helping track changes in water volume over time, the data will better equip scientists and water resource managers to monitor how much water flows into and out of Earth’s freshwater bodies.
SWOT is a collaboration between NASA and the French space agency Centre National d’Études Spatial (CNES), with contributions from the Canadian Space Agency (CSA) and the UK Space Agency. NASA’s Launch Services Program, based at the agency’s Kennedy Space Center in Florida, is managing the launch service.