Members Can Post Anonymously On This Site
-
Similar Topics
-
By NASA
6 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
The SWOT satellite is helping scientists size up flood waves on waterways like the Yellowstone River, pictured here in October 2024 in Montana. SWOT measures the height of surface waters, including the ocean, and hundreds of thousands of rivers, lakes, and reservoirs in the U.S. alone.NPS In a first, researchers from NASA and Virginia Tech used satellite data to measure the height and speed of potentially hazardous flood waves traveling down U.S. rivers. The three waves they tracked were likely caused by extreme rainfall and by a loosened ice jam. While there is currently no database that compiles satellite data on river flood waves, the new study highlights the potential of space-based observations to aid hydrologists and engineers, especially those working in communities along river networks with limited flood control structures such as levees and flood gates.
Unlike ocean waves, which are ordinarily driven by wind and tides, and roll to shore at a steady clip, river waves (also called flood or flow waves) are temporary surges stretching tens to hundreds of miles. Typically caused by rainfall or seasonal snowmelt, they are essential to shuttling nutrients and organisms down a river. But they can also pose hazards: Extreme river waves triggered by a prolonged downpour or dam break can produce floods.
“Ocean waves are well known from surfing and sailing, but rivers are the arteries of the planet. We want to understand their dynamics,” said Cedric David, a hydrologist at NASA’s Jet Propulsion Laboratory in Southern California and a coauthor of a new study published May 14 in Geophysical Research Letters.
SWOT is depicted in orbit in this artist’s concept, with sunlight glinting off one of its solar panels and both antennas of its key instrument — the Ka-band Radar Interferometer (KaRIn) — extended. The antennas collect data along a swath 30 miles (50 kilometers) wide on either side of the satellite.CNES Measuring Speed and Size
To search for river waves for her doctoral research, lead author Hana Thurman of Virginia Tech turned to a spacecraft launched in 2022. The SWOT (Surface Water and Ocean Topography) satellite is a collaboration between NASA and the French space agency CNES (Centre National d’Études Spatiales). It is surveying the height of nearly all of Earth’s surface waters, both fresh and salty, using its sensitive Ka-band Radar Interferometer (KaRIn). The instrument maps the elevation and width of water bodies by bouncing microwaves off the surface and timing how long the signal takes to return.
“In addition to monitoring total storage of waters in lakes and rivers, we zoom in on dynamics and impacts of water movement and change,” said Nadya Vinogradova Shiffer, SWOT program scientist at NASA Headquarters in Washington.
Thurman knew that SWOT has helped scientists track rising sea levels near the coast, spot tsunami slosh, and map the seafloor, but could she identify river height anomalies in the data indicating a wave on the move?
She found that the mission had caught three clear examples of river waves, including one that arose abruptly on the Yellowstone River in Montana in April 2023. As the satellite passed overhead, it observed a 9.1-foot-tall (2.8-meter-tall) crest flowing toward the Missouri River in North Dakota. It was divided into a dramatic 6.8-mile-long (11-kilometer-long) peak followed by a more drawn‐out tail. These details are exciting to see from orbit and illustrate the KaRIn instrument’s uniquely high spatial resolution, Thurman said.
Sleuthing through optical Sentinel-2 imagery of the area, she determined that the wave likely resulted from an ice jam breaking apart upstream and releasing pent-up water.
The other two river waves that Thurman and the team found were triggered by rainfall runoff. One, spotted by SWOT starting on Jan. 25, 2024, on the Colorado River south of Austin, Texas, was associated with the largest flood of the year on that section of river. Measuring over 30 feet (9 meters) tall and 166 miles (267 kilometers) long, it traveled around 3.5 feet (1.07 meters) per second for over 250 miles (400 kilometers) before discharging into Matagorda Bay.
The other wave originated on the Ocmulgee River near Macon, Georgia, in March 2024. Measuring over 20 feet (6 meters) tall and extending more than 100 miles (165 kilometers), it traveled about a foot (0.33 meters) per second for more than 124 miles (200 kilometers).
“We’re learning more about the shape and speed of flow waves, and how they change along long stretches of river,” Thurman said. “That could help us answer questions like, how fast could a flood get here and is infrastructure at risk?”
Complementary Observations
Engineers and water managers measuring river waves have long relied on stream gauges, which record water height and estimate discharge at fixed points along a river. In the United States, stream gauge networks are maintained by agencies including the U.S. Geological Survey. They are sparser in other parts of the world.
“Satellite data is complementary because it can help fill in the gaps,” said study supervisor George Allen, a hydrologist and remote sensing expert at Virginia Tech.
If stream gauges are like toll booths clocking cars as they pass, SWOT is like a traffic helicopter taking snapshots of the highway.
The wave speeds that SWOT helped determine were similar to those calculated using gauge data alone, Allen said, showing how the satellite could help monitor waves in river basins without gauges. Knowing where and why river waves develop can help scientists tracking changing flood patterns around the world.
Orbiting Earth multiple times each day, SWOT is expected to observe some 55% of large-scale floods at some stage in their life cycle. “If we see something in the data, we can say something,” David said of SWOT’s potential to flag dangerous floods in the making. “For a long time, we’ve stood on the banks of our rivers, but we’ve never seen them like we are now.”
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. NASA’s Jet Propulsion Laboratory, managed for the agency by Caltech in Pasadena, California, 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.
News Media Contacts
Jane J. Lee / Andrew Wang
Jet Propulsion Laboratory, Pasadena, Calif.
818-354-0307 / 626-379-6874
Written by Sally Younger
2025-074
Share
Details
Last Updated May 21, 2025 Related Terms
SWOT (Surface Water and Ocean Topography) Jet Propulsion Laboratory Explore More
3 min read Devil’s in Details in Selfie Taken by NASA’s Mars Perseverance Rover
Article 2 hours ago 5 min read NASA’s Perseverance Mars Rover to Take Bite Out of ‘Krokodillen’
Article 2 days ago 6 min read NASA, French SWOT Satellite Offers Big View of Small Ocean Features
Article 6 days ago Keep Exploring Discover Related Topics
Missions
Humans in Space
Climate Change
Solar System
View the full article
-
By Space Force
128 Air Force Reserve Professionals who will transfer into the Space Force in a full-time capacity.
View the full article
-
By NASA
4 min read
Preparations for Next Moonwalk Simulations Underway (and Underwater)
The Starling swarm’s extended mission tested advanced autonomous maneuvering capabilities.NASA/Daniel Rutter As missions to low Earth orbit become more frequent, space traffic coordination remains a key element to efficiently operating in space. Different satellite operators using autonomous systems need to operate together and manage increasing workloads. NASA’s Starling spacecraft swarm recently tested a coordination with SpaceX’s Starlink constellation, demonstrating a potential solution to enhance space traffic coordination.
Led by the Small Spacecraft Technology program at NASA’s Ames Research Center in California’s Silicon Valley, Starling originally set out to demonstrate autonomous planning and execution of orbital maneuvers with the mission’s four small spacecraft. After achieving its primary objectives, the Starling mission expanded to become Starling 1.5, an experiment to demonstrate maneuvers between the Starling swarm and SpaceX’s Starlink satellites, which also maneuver autonomously.
Coordination in Low Earth Orbit
Current space traffic coordination systems screen trajectories of spacecraft and objects in space and alert operators on the ground of potential conjunctions, which occur when two objects exceed an operator’s tolerance for a close approach along their orbital paths. Spacecraft operators can request notification at a range of probabilities, often anywhere from a 1 in 10,000 likelihood of a collision to 1 in 1,000,000 or lower.
Conjunction mitigation between satellite operators requires manual coordination through calls or emails on the ground. An operator may receive a notification for a number of reasons including recently maneuvering their satellite, nearby space debris, or if another satellite adjusts its orbit.
Once an operator is aware of a potential conjunction, they must work together with other operators to reduce the probability of a collision. This can result in time-consuming calls or emails between ground operations teams with different approaches to safe operations. It also means maneuvers may require several days to plan and implement. This timeline can be challenging for missions that require quick adjustments to capture important data.
“Occasionally, we’ll do a maneuver that we find out wasn’t necessary if we could have waited before making a decision. Sometimes you can’t wait three days to reposition and observe. Being able to react within a few hours can make new satellite observations possible,” said Nathan Benz, project manager of Starling 1.5 at NASA Ames.
Improving Coordination for Autonomous Maneuvering
The first step in improving coordination was to develop a reliable way to signal maneuver responsibility between operators. “Usually, SpaceX takes the responsibility to move out of the way when another operator shares their predicted trajectory information,” said Benz.
SpaceX and NASA collaborated to design a conjunction screening service, which SpaceX then implemented. Satellite operators can submit trajectories and receive conjunction data quickly, then accept responsibility to maneuver away from a potential conjunction.
“For this experiment, NASA’s Starling accepted responsibility to move using the screening service, successfully tested our system’s performance, then autonomously planned and executed the maneuver for the NASA Starling satellite, resolving a close approach with a Starlink satellite,” said Benz.
Through NASA’s Starling 1.5 experiment, the agency helped validate SpaceX’s Starlink screening service. The Office of Space Commerce within the U.S. Department of Commerce also worked with SpaceX to understand and assess the Starlink screening service.
Quicker Response to Changes on Earth
The time it takes to plan maneuvers in today’s orbital traffic environment limits the number of satellites a human operator can manage and their ability to collect data or serve customers.
“A fully automated system that is flexible and adaptable between satellite constellations is ideal for an environment of multiple satellite operators, all of whom have differing criteria for mitigating collision risks,” said Lauri Newman, program officer for NASA’s Conjunction Assessment Risk Analysis program at the agency’s headquarters in Washington.
Reducing the time necessary to plan maneuvers could open up a new class of missions, where quick responses to changes in space or on Earth’s surface are possible. Satellites capable of making quicker movements could adjust their orbital position to capture a natural disaster from above, or respond to one swarm member’s interesting observations, moving to provide a more thorough look.
“With improved access and use of low Earth orbit and the necessity to provide a more advanced space traffic coordination system, Starling 1.5 is providing critical data. Starling 1.5 is the result of a successful partnership between NASA, the Department of Commerce, and SpaceX, maturing technology to solve such challenges,” said Roger Hunter, program manager of the Small Spacecraft Technology program. “We look forward to the sustained impact of the Starling technologies as they continue demonstrating advancements in spacecraft coordination, cooperation, and autonomy.”
NASA Ames leads the Starling projects. NASA’s Small Spacecraft Technology program within the Space Technology Mission Directorate funds and manages the Starling mission.
Share
Details
Last Updated Mar 26, 2025 LocationAmes Research Center Related Terms
Ames Research Center General Small Spacecraft Technology Program Space Technology Mission Directorate Explore More
2 min read The Sky’s Not the Limit: Testing Precision Landing Tech for Future Space Missions
Article 58 seconds ago 2 min read NASA Cloud Software Helps Companies Find their Place in Space
Article 20 hours ago 5 min read NASA Demonstrates New Wildland Fire Airspace Management System
Article 22 hours ago Keep Exploring Discover More Topics From NASA
Ames Research Center
Space Technology Mission Directorate
Conjunction Assessment (CA Home)
Starling
View the full article
-
By NASA
6 Min Read NASA’s Webb Captures Neptune’s Auroras For First Time
At the left, an enhanced-color image of Neptune from NASA’s Hubble Space Telescope. At the right, that image is combined with data from NASA’s James Webb Space Telescope. Credits:
NASA, ESA, CSA, STScI, Heidi Hammel (AURA), Henrik Melin (Northumbria University), Leigh Fletcher (University of Leicester), Stefanie Milam (NASA-GSFC) Long-sought auroral glow finally emerges under Webb’s powerful gaze
For the first time, NASA’s James Webb Space Telescope has captured bright auroral activity on Neptune. Auroras occur when energetic particles, often originating from the Sun, become trapped in a planet’s magnetic field and eventually strike the upper atmosphere. The energy released during these collisions creates the signature glow.
In the past, astronomers have seen tantalizing hints of auroral activity on Neptune, for example, in the flyby of NASA’s Voyager 2 in 1989. However, imaging and confirming the auroras on Neptune has long evaded astronomers despite successful detections on Jupiter, Saturn, and Uranus. Neptune was the missing piece of the puzzle when it came to detecting auroras on the giant planets of our solar system.
“Turns out, actually imaging the auroral activity on Neptune was only possible with Webb’s near-infrared sensitivity,” said lead author Henrik Melin of Northumbria University, who conducted the research while at the University of Leicester. “It was so stunning to not just see the auroras, but the detail and clarity of the signature really shocked me.”
The data was obtained in June 2023 using Webb’s Near-Infrared Spectrograph. In addition to the image of the planet, astronomers obtained a spectrum to characterize the composition and measure the temperature of the planet’s upper atmosphere (the ionosphere). For the first time, they found an extremely prominent emission line signifying the presence of the trihydrogen cation (H3+), which can be created in auroras. In the Webb images of Neptune, the glowing aurora appears as splotches represented in cyan.
Image A:
Neptune’s Auroras – Hubble and Webb
At the left, an enhanced-color image of Neptune from NASA’s Hubble Space Telescope. At the right, that image is combined with data from NASA’s James Webb Space Telescope. The cyan splotches, which represent auroral activity, and white clouds, are data from Webb’s Near-Infrared Spectrograph (NIRSpec), overlayed on top of the full image of the planet from Hubble’s Wide Field Camera 3. NASA, ESA, CSA, STScI, Heidi Hammel (AURA), Henrik Melin (Northumbria University), Leigh Fletcher (University of Leicester), Stefanie Milam (NASA-GSFC) “H3+ has a been a clear signifier on all the gas giants — Jupiter, Saturn, and Uranus — of auroral activity, and we expected to see the same on Neptune as we investigated the planet over the years with the best ground-based facilities available,” explained Heidi Hammel of the Association of Universities for Research in Astronomy, Webb interdisciplinary scientist and leader of the Guaranteed Time Observation program for the Solar System in which the data were obtained. “Only with a machine like Webb have we finally gotten that confirmation.”
The auroral activity seen on Neptune is also noticeably different from what we are accustomed to seeing here on Earth, or even Jupiter or Saturn. Instead of being confined to the planet’s northern and southern poles, Neptune’s auroras are located at the planet’s geographic mid-latitudes — think where South America is located on Earth.
This is due to the strange nature of Neptune’s magnetic field, originally discovered by Voyager 2 in 1989 which is tilted by 47 degrees from the planet’s rotation axis. Since auroral activity is based where the magnetic fields converge into the planet’s atmosphere, Neptune’s auroras are far from its rotational poles.
The ground-breaking detection of Neptune’s auroras will help us understand how Neptune’s magnetic field interacts with particles that stream out from the Sun to the distant reaches of our solar system, a totally new window in ice giant atmospheric science.
From the Webb observations, the team also measured the temperature of the top of Neptune’s atmosphere for the first time since Voyager 2’s flyby. The results hint at why Neptune’s auroras remained hidden from astronomers for so long.
“I was astonished — Neptune’s upper atmosphere has cooled by several hundreds of degrees,” Melin said. “In fact, the temperature in 2023 was just over half of that in 1989.”
Through the years, astronomers have predicted the intensity of Neptune’s auroras based on the temperature recorded by Voyager 2. A substantially colder temperature would result in much fainter auroras. This cold temperature is likely the reason that Neptune’s auroras have remained undetected for so long. The dramatic cooling also suggests that this region of the atmosphere can change greatly even though the planet sits over 30 times farther from the Sun compared to Earth.
Equipped with these new findings, astronomers now hope to study Neptune with Webb over a full solar cycle, an 11-year period of activity driven by the Sun’s magnetic field. Results could provide insights into the origin of Neptune’s bizarre magnetic field, and even explain why it’s so tilted.
“As we look ahead and dream of future missions to Uranus and Neptune, we now know how important it will be to have instruments tuned to the wavelengths of infrared light to continue to study the auroras,” added Leigh Fletcher of Leicester University, co-author on the paper. “This observatory has finally opened the window onto this last, previously hidden ionosphere of the giant planets.”
These observations, led by Fletcher, were taken as part of Hammel’s Guaranteed Time Observation program 1249. The team’s results have been published in Nature Astronomy.
The James Webb Space Telescope is the world’s premier space science observatory. Webb is solving mysteries in our solar system, looking beyond to distant worlds around other stars, and probing the mysterious structures and origins of our universe and our place in it. Webb is an international program led by NASA with its partners, ESA (European Space Agency) and CSA (Canadian Space Agency).
Downloads
Click any image to open a larger version.
View/Download all image products at all resolutions for this article from the Space Telescope Science Institute.
Read the research results published in Nature Astronomy.
Media Contacts
Laura Betz – laura.e.betz@nasa.gov
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Hannah Braun- hbraun@stsci.edu
Space Telescope Science Institute, Baltimore, Maryland
Christine Pulliam – cpulliam@stsci.edu
Space Telescope Science Institute, Baltimore, Md.
Science
Henrik Melin (Northumbria University)
Related Information
View more: Webb images of Neptune
Watch: Visualization of Neptune’s tilted magnetic axis
Learn more : about Neptune
More Webb News
More Webb Images
Webb Science Themes
Webb Mission Page
Related For Kids
About Neptune
About the Solar System
What is the Webb Telescope?
SpacePlace for Kids
En Español
Ciencia de la NASA
NASA en español
Space Place para niños
Keep Exploring Related Topics
James Webb Space Telescope
Webb is the premier observatory of the next decade, serving thousands of astronomers worldwide. It studies every phase in the…
Neptune
Neptune Stories
Our Solar System
Share
Details
Last Updated Mar 25, 2025 Editor Stephen Sabia Contact Laura Betz laura.e.betz@nasa.gov Related Terms
James Webb Space Telescope (JWST) Astrophysics Goddard Space Flight Center Neptune Planetary Science Planets Science & Research The Solar System View the full article
-
By European Space Agency
Image: ESA's Atomic Clock Ensemble in Space at NASA's Kennedy Space Center View the full article
-
-
Check out these Videos
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.