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By NASA
NASA NASA astronaut Franklin Chang-Diaz works with a grapple fixture during a June 2002 spacewalk outside of the International Space Station. He was partnered with CNES (Centre National d’Etudes Spatiales) astronaut Philippe Perrin for the spacewalk – one of three that occurred during the STS-111 mission. Chang-Diaz was part of NASA’s ninth class of astronaut candidates. He became the first Hispanic American to fly in space.
Image credit: NASA
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By NASA
3 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Earth scientist Compton J. Tucker has been elected to the National Academy of Sciences for his work creating innovative tools to track the planet’s changing vegetation from space. It’s research that has spanned nearly 50 years at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, where he is a visiting scientist after retiring in March.
Tucker’s research began with identifying wavelengths of light that are absorbed or reflected as plants undergo photosynthesis, and has evolved into calculating the health and productivity of vegetation over time with satellites.
“I’m honored and surprised,” Tucker said of his election. “There were opportunities at the Goddard Space Flight Center that have enabled this work that couldn’t be found elsewhere. There were people who built satellites, who understood satellite data, and had the computer code to process it. All the work I’ve done has been part of a team, with other people contributing in different ways. Working at NASA is a team effort of science and discovery that’s fun and intellectually rewarding.”
Earth scientist Compton Tucker, who has studied remote sensing of vegetation at NASA Goddard for 50 years, has been elected to the National Academy of Sciences.Courtesy Compton Tucker Tucker earned his master’s and doctoral degrees from Colorado State University, where he worked on a National Science Foundation-funded project analyzing spectrometer data of grassland ecosystems. In 1975, he came to NASA Goddard as a postdoctoral fellow and used what he learned in his graduate work to modify the imager on National Oceanic and Atmospheric Administration (NOAA) meteorological satellites and modify Landsat’s thematic mapper instrument.
He became a civil servant at the agency in 1977, and continued work with radiometers to study vegetation – first with handheld devices, then with NOAA’s Advanced Very High Resolution Radiometer satellite instruments. He has also used data from Landsat satellites, Moderate Resolution Imaging Spectroradiometer instruments, and commercial satellites. His scientific papers have been cited 100,000 times, and one of his recent studies mapped 10 billion individual trees across Africa’s drylands to inventory carbon storage at the tree level.
“The impact of Compton Tucker’s work over the last half-century at Goddard is incredible,” said Dalia Kirschbaum, director of the Earth Sciences Division at NASA Goddard. “Among his many achievements, he essentially developed the technique of using satellites to study photosynthesis from plants, which people have used to monitor droughts, forecast crop shortages, defeat the desert locust, and even predict disease outbreaks. This is a well-deserved honor.”
Goddard scientist Compton Tucker’s work using remote sensing instruments to study vegetation involved field work in Iceland in 1976, left, graduate student research at Colorado State University in the early 1970s, top right, and analyzing satellite data stored on tape reels at Goddard.Courtesy Compton Tucker The National Academy of Sciences was proposed by Abraham Lincoln and established by Congress in 1863, charged with advising the United States on science and technology. Each year, up to 120 new members are elected “in recognition of their distinguished and continuing achievements in original research,” according to the organization.
In addition his role as a visiting scientist at Goddard, Tucker is also an adjunct professor at the University of Maryland and a consulting scholar at the University of Pennsylvania’s University Museum. He was awarded the National Air and Space Collins Trophy for Current Achievement in 1993 and the Vega Medal by the Swedish Society of Anthropology and Geography in 2014. He is a fellow of the American Association for the Advancement of Science and the American Geophysical Union, and won the Senior Executive Service Presidential Rank Award for Meritorious Service in 2017, among other honors.
By Kate Ramsayer
NASA’s Goddard Space Flight Center, Greenbelt, Md.
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Last Updated Jun 05, 2025 EditorErica McNameeContactKate D. Ramsayerkate.d.ramsayer@nasa.govLocationNASA Goddard Space Flight Center Related Terms
Goddard Space Flight Center Earth General Landsat Moderate Resolution Imaging Spectroradiometer (MODIS) View the full article
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By European Space Agency
After an extraordinary six-week voyage from northern Norway, the iconic Norwegian tall ship Statsraad Lehmkuhl has docked in Nice, France, concluding ESA’s 2025 Advanced Ocean Training course. Braving everything from wild storms to calm near-freezing seas, students aboard mastered techniques for collecting ocean measurements and harnessed satellite data to unlock insights into our blue planet.
Led by experts, this real-world expedition offered more than education – it sparked curiosity and a deeper commitment to understanding and protecting our oceans.
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By NASA
6 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
Sunlight reflects off the ocean surface near Norfolk, Virginia, in this 1991 space shuttle image, highlighting swirling patterns created by features such as internal waves, which are produced when the tide moves over underwater features. Data from the international SWOT mission is revealing the role of smaller-scale waves and eddies.NASA The international mission collects two-dimensional views of smaller waves and currents that are bringing into focus the ocean’s role in supporting life on Earth.
Small things matter, at least when it comes to ocean features like waves and eddies. A recent NASA-led analysis using data from the SWOT (Surface Water and Ocean Topography) satellite found that ocean features as small as a mile across potentially have a larger impact on the movement of nutrients and heat in marine ecosystems than previously thought.
Too small to see well with previous satellites but too large to see in their entirety with ship-based instruments, these relatively small ocean features fall into a category known as the submesoscale. The SWOT satellite, a joint effort between NASA and the French space agency CNES (Centre National d’Études Spatiales), can observe these features and is demonstrating just how important they are, driving much of the vertical transport of things like nutrients, carbon, energy, and heat within the ocean. They also influence the exchange of gases and energy between the ocean and atmosphere.
“The role that submesoscale features play in ocean dynamics is what makes them important,” said Matthew Archer, an oceanographer at NASA’s Jet Propulsion Laboratory in Southern California. Some of these features are called out in the animation below, which was created using SWOT sea surface height data.
This animation shows small ocean features — including internal waves and eddies — derived from SWOT observations in the Indian, Atlantic, and Pacific oceans, as well as the Mediterranean Sea. White and lighter blue represent higher ocean surface heights compared to darker blue areas. The purple colors shown in one location represent ocean current speeds.
NASA’s Scientific Visualization Studio “Vertical currents move heat between the atmosphere and ocean, and in submesoscale eddies, can actually bring up heat from the deep ocean to the surface, warming the atmosphere,” added Archer, who is a coauthor on the submesoscale analysis published in April in the journal Nature. Vertical circulation can also bring up nutrients from the deep sea, supplying marine food webs in surface waters like a steady stream of food trucks supplying festivalgoers.
“Not only can we see the surface of the ocean at 10 times the resolution of before, we can also infer how water and materials are moving at depth,” said Nadya Vinogradova Shiffer, SWOT program scientist at NASA Headquarters in Washington.
Fundamental Force
Researchers have known about these smaller eddies, or circular currents, and waves for decades. From space, Apollo astronauts first spotted sunlight glinting off small-scale eddies about 50 years ago. And through the years, satellites have captured images of submesoscale ocean features, providing limited information such as their presence and size. Ship-based sensors or instruments dropped into the ocean have yielded a more detailed view of submesoscale features, but only for relatively small areas of the ocean and for short periods of time.
The SWOT satellite measures the height of water on nearly all of Earth’s surface, including the ocean and freshwater bodies, at least once every 21 days. The satellite gives researchers a multidimensional view of water levels, which they can use to calculate, for instance, the slope of a wave or eddy. This in turn yields information on the amount of pressure, or force, being applied to the water in the feature. From there, researchers can figure out how fast a current is moving, what’s driving it and —combined with other types of information — how much energy, heat, or nutrients those currents are transporting.
“Force is the fundamental quantity driving fluid motion,” said study coauthor Jinbo Wang, an oceanographer at Texas A&M University in College Station. Once that quantity is known, a researcher can better understand how the ocean interacts with the atmosphere, as well as how changes in one affect the other.
Prime Numbers
Not only was SWOT able to spot a submesoscale eddy in an offshoot of the Kuroshio Current — a major current in the western Pacific Ocean that flows past the southeast coast of Japan — but researchers were also able to estimate the speed of the vertical circulation within that eddy. When SWOT observed the feature, the vertical circulation was likely 20 to 45 feet (6 to 14 meters) per day.
This is a comparatively small amount for vertical transport. However, the ability to make those calculations for eddies around the world, made possible by SWOT, will improve researchers’ understanding of how much energy, heat, and nutrients move between surface waters and the deep sea.
Researchers can do similar calculations for such submesoscale features as an internal solitary wave — a wave driven by forces like the tide sloshing over an underwater plateau. The SWOT satellite spotted an internal wave in the Andaman Sea, located in the northeastern part of the Indian Ocean off Myanmar. Archer and colleagues calculated that the energy contained in that solitary wave was at least twice the amount of energy in a typical internal tide in that region.
This kind of information from SWOT helps researchers refine their models of ocean circulation. A lot of ocean models were trained to show large features, like eddies hundreds of miles across, said Lee Fu, SWOT project scientist at JPL and a study coauthor. “Now they have to learn to model these smaller scale features. That’s what SWOT data is helping with.”
Researchers have already started to incorporate SWOT ocean data into some models, including NASA’s ECCO (Estimating the Circulation and Climate of the Ocean). It may take some time until SWOT data is fully a part of models like ECCO. But once it is, the information will help researchers better understand how the ocean ecosystem will react to a changing world.
More About SWOT
The SWOT satellite was jointly developed by NASA and CNES, with contributions from the Canadian Space Agency (CSA) and the UK Space Agency. Managed for NASA by Caltech in Pasadena, California, JPL leads the U.S. component of the project. For the flight system payload, NASA provided the Ka-band radar interferometer (KaRIn) instrument, a GPS science receiver, a laser retroreflector, a two-beam microwave radiometer, and NASA instrument operations. The Doppler Orbitography and Radioposition Integrated by Satellite 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 satellite platform, and ground operations were provided by CNES. The KaRIn high-power transmitter assembly was provided by CSA.
To learn more about SWOT, visit:
https://swot.jpl.nasa.gov
News Media Contacts
Jane J. Lee / Andrew Wang
Jet Propulsion Laboratory, Pasadena, Calif.
626-491-1943 / 626-379-6874
jane.j.lee@jpl.nasa.gov / andrew.wang@jpl.nasa.gov
2025-070
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Last Updated May 15, 2025 Related Terms
SWOT (Surface Water and Ocean Topography) Jet Propulsion Laboratory Oceanography Oceans Explore More
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