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By NASA
Illustration of the main asteroid belt, orbiting the Sun between Mars and JupiterNASA NASA’s powerful James Webb Space Telescope includes asteroids on its list of objects studied and secrets revealed.
A team led by researchers at the Massachusetts Institute of Technology (MIT) in Cambridge repurposed Webb’s observations of a distant star to reveal a population of small asteroids — smaller than astronomers had ever detected orbiting the Sun in the main asteroid belt between Mars and Jupiter.
The 138 new asteroids range from the size of a bus to the size of a stadium — a size range in the main belt that has not been observable with ground-based telescopes. Knowing how many main belt asteroids are in different size ranges can tell us something about how asteroids have been changed over time by collisions. That process is related to how some of them have escaped the main belt over the solar system’s history, and even how meteorites end up on Earth.
“We now understand more about how small objects in the asteroid belt are formed and how many there could be,” said Tom Greene, an astrophysicist at NASA’s Ames Research Center in California’s Silicon Valley and co-author on the paper presenting the results. “Asteroids this size likely formed from collisions between larger ones in the main belt and are likely to drift towards the vicinity of Earth and the Sun.”
Insights from this research could inform the work of the Asteroid Threat Assessment Project at Ames. ATAP works across disciplines to support NASA’s Planetary Defense Coordination Office by studying what would happen in the case of an Earth impact and modeling the associated risks.
“It’s exciting that Webb’s capabilities can be used to glean insights into asteroids,” said Jessie Dotson, an astrophysicist at Ames and member of ATAP. “Understanding the sizes, numbers, and evolutionary history of smaller main belt asteroids provides important background about the near-Earth asteroids we study for planetary defense.”
Illustration of the James Webb Space TelescopeNASA The team that made the asteroid detections, led by research scientist Artem Burdanov and professor of planetary science Julien de Wit, both of MIT, developed a method to analyze existing Webb images for the presence of asteroids that may have been inadvertently “caught on film” as they passed in front of the telescope. Using the new image processing technique, they studied more than 10,000 images of the star TRAPPIST-1, originally taken to search for atmospheres around planets orbiting the star, in the search for life beyond Earth.
Asteroids shine more brightly in infrared light, the wavelength Webb is tuned to detect, than in visible light, helping reveal the population of main belt asteroids that had gone unnoticed until now. NASA will also take advantage of that infrared glow with an upcoming mission, the Near-Earth Object (NEO) Surveyor. NEO Surveyor is the first space telescope specifically designed to hunt for near-Earth asteroids and comets that may be potential hazards to Earth.
The paper presenting this research, “Detections of decameter main-belt asteroids with JWST,” was published Dec. 9 in Nature.
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).
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Members of the news media interested in covering this topic should reach out to the NASA Ames newsroom.
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By NASA
NASA’s Dawn spacecraft captured this image of Vesta as it left the giant asteroid’s orbit in 2012. The framing camera was looking down at the north pole, which is in the middle of the image.NASA/JPL-Caltech/UCLA/MPS/DLR/IDA Known as flow formations, these channels could be etched on bodies that would seem inhospitable to liquid because they are exposed to the extreme vacuum conditions of space.
Pocked with craters, the surfaces of many celestial bodies in our solar system provide clear evidence of a 4.6-billion-year battering by meteoroids and other space debris. But on some worlds, including the giant asteroid Vesta that NASA’s Dawn mission explored, the surfaces also contain deep channels, or gullies, whose origins are not fully understood.
A prime hypothesis holds that they formed from dry debris flows driven by geophysical processes, such as meteoroid impacts, and changes in temperature due to Sun exposure. A recent NASA-funded study, however, provides some evidence that impacts on Vesta may have triggered a less-obvious geologic process: sudden and brief flows of water that carved gullies and deposited fans of sediment. By using lab equipment to mimic conditions on Vesta, the study, which appeared in Planetary Science Journal, detailed for the first time what the liquid could be made of and how long it would flow before freezing.
Although the existence of frozen brine deposits on Vesta is unconfirmed, scientists have previously hypothesized that meteoroid impacts could have exposed and melted ice that lay under the surface of worlds like Vesta. In that scenario, flows resulting from this process could have etched gullies and other surface features that resemble those on Earth.
To explore potential explanations for deep channels, or gullies, seen on Vesta, scientists used JPL’s Dirty Under-vacuum Simulation Testbed for Icy Environments, or DUSTIE, to simulate conditions on the giant asteroid that would occur after meteoroids strike the surface.NASA/JPL-Caltech But how could airless worlds — celestial bodies without atmospheres and exposed to the intense vacuum of space — host liquids on the surface long enough for them to flow? Such a process would run contrary to the understanding that liquids quickly destabilize in a vacuum, changing to a gas when the pressure drops.
“Not only do impacts trigger a flow of liquid on the surface, the liquids are active long enough to create specific surface features,” said project leader and planetary scientist Jennifer Scully of NASA’s Jet Propulsion Laboratory in Southern California, where the experiments were conducted. “But for how long? Most liquids become unstable quickly on these airless bodies, where the vacuum of space is unyielding.”
The critical component turns out to be sodium chloride — table salt. The experiments found that in conditions like those on Vesta, pure water froze almost instantly, while briny liquids stayed fluid for at least an hour. “That’s long enough to form the flow-associated features identified on Vesta, which were estimated to require up to a half-hour,” said lead author Michael J. Poston of the Southwest Research Institute in San Antonio.
Launched in 2007, the Dawn spacecraft traveled to the main asteroid belt between Mars and Jupiter to orbit Vesta for 14 months and Ceres for almost four years. Before ending in 2018, the mission uncovered evidence that Ceres had been home to a subsurface reservoir of brine and may still be transferring brines from its interior to the surface. The recent research offers insights into processes on Ceres but focuses on Vesta, where ice and salts may produce briny liquid when heated by an impact, scientists said.
Re-creating Vesta
To re-create Vesta-like conditions that would occur after a meteoroid impact, the scientists relied on a test chamber at JPL called the Dirty Under-vacuum Simulation Testbed for Icy Environments, or DUSTIE. By rapidly reducing the air pressure surrounding samples of liquid, they mimicked the environment around fluid that comes to the surface. Exposed to vacuum conditions, pure water froze instantly. But salty fluids hung around longer, continuing to flow before freezing.
The brines they experimented with were a little over an inch (a few centimeters) deep; scientists concluded the flows on Vesta that are yards to tens of yards deep would take even longer to refreeze.
The researchers were also able to re-create the “lids” of frozen material thought to form on brines. Essentially a frozen top layer, the lids stabilize the liquid beneath them, protecting it from being exposed to the vacuum of space — or, in this case the vacuum of the DUSTIE chamber — and helping the liquid flow longer before freezing again.
This phenomenon is similar to how on Earth lava flows farther in lava tubes than when exposed to cool surface temperatures. It also matches up with modeling research conducted around potential mud volcanoes on Mars and volcanoes that may have spewed icy material from volcanoes on Jupiter’s moon Europa.
“Our results contribute to a growing body of work that uses lab experiments to understand how long liquids last on a variety of worlds,” Scully said.
Find more information about NASA’s Dawn mission here:
https://science.nasa.gov/mission/dawn/
News Media Contacts
Gretchen McCartney
Jet Propulsion Laboratory, Pasadena, Calif.
818-287-4115
gretchen.p.mccartney@jpl.nasa.gov
Karen Fox / Molly Wasser
NASA Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov
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Last Updated Dec 20, 2024 Related Terms
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By NASA
Earth (ESD) Earth Home Explore Climate Change Science in Action Multimedia Data For Researchers 14 Min Read NASA’s Brad Doorn Brings Farm Belt Wisdom to Space-Age Agriculture
This image shows corn cultivation patterns across the U.S. Midwest in 2020, with lands planted in corn marked in yellow. Credits:
NASA Earth Observatory/ Lauren Dauphin Bradley Doorn grew up in his family’s trucking business, which hauled milk and animal feed across the sprawling plains of South Dakota. Home was Mitchell, a small town famous for its Corn Palace, where murals crafted from corn kernels and husks have adorned its facade since 1892—a tribute to the abundance of the surrounding farmland.
Trucking was often grueling work for the family, the day breaking early and ending in headlights. Like farming, driving a truck wasn’t just a job; it was the engine of daily life, thrumming through nearly every conversation and decision.
Brad loved the outdoors, and by the time he started college in the early 1980s, studying geological engineering felt like a natural fit. “I wanted to be out in the field somewhere, working under the big skies of the West,” Brad recalled. But in his sophomore year at the South Dakota School of Mines and Technology, the tuition money dried up.
Dean Doorn, Brad Doorn’s father, stands beside a milk truck used in the family’s business of hauling milk across South Dakota in the 1960s and ’70s. Credit: B. Doorn Doorn found himself at a crossroads familiar to many in rural America: return to the certainty of a family trade or chart a new route. “That’s when the Army stepped in,” he said. The ROTC program offered a way to continue with school and a path into the world of remote sensing—a field that would come to define his career.
Brad’s choice to join the Army would eventually place him at the forefront of a mapping revolution, equipping him to see and analyze Earth in ways never possible before the advent of satellites. But more than the technical skills, the military showed him the allure of a life anchored to mission and team.
Even as his career took him far from Mitchell, Doorn would remain connected to his rural America roots. Today, he leads NASA’s agriculture programs within the agency’s Earth Science Division. “My family wasn’t made up of farmers, but farming was a part of everything growing up,” said Brad. “Even now, working with NASA, that connection to the land—the sense of how weather, crops, and people are tied together—it’s still in everything I do.”
Amid the dazzle of NASA’s feats exploring the solar system and universe, it’s easy to miss the agency’s quiet work in fields of soy and wheat. But for more than 60 years, the agency has harnessed the power of its satellites to deliver crucial data on temperature, precipitation, crop yields, and more to farmers, policymakers, and food security experts worldwide.
The Landsat 9 satellite captured this false-color image of Louisiana rice fields in February 2023. Dark blue shows flooded areas, while green indicates vegetation. Grid-like levees separate fields pre-planting. Louisiana is the third largest producer of rice in the U.S. Credit: NASA Earth Observatory/ Lauren Dauphin From orbit, satellites beam down streams of data—numbers and pixels that, when paired with farmers’ knowledge of the land, can guide growers as they adjust irrigation levels or plan for the next planting. But the satellites don’t just yield data; they tell stories that call for action, enabling nations to brace for droughts, floods, and the prospect of empty grain silos.
“Under Brad’s guidance, NASA’s agriculture program has become a global leader for satellite-driven solutions, tackling food security and sustainability head-on,” said Lawrence Friedl, the senior engagement officer for NASA Earth Science. Reflecting on years of collaboration, he added: “I am so impressed and grateful for what he and his teams have accomplished.”
Boots Meet Satellites in the First Gulf War
Long before Brad began guiding NASA’s agricultural initiatives, he was already navigating tricky terrain, both literal and figurative, with satellite imagery. His career in remote sensing didn’t start with crops, but with the deserts of Iraq and Kuwait.
As part of the Army’s 18th Airborne Corps, Brad led a company at Fort Bragg (now Fort Liberty) in North Carolina that had just returned from operations in the First Gulf War, in the early 1990s. “I loved being part of a unit, part of something bigger than just me,” Brad recalled. “It felt good to have that purpose and mission.”
Far from the combat zone, Doorn’s company became cartographers of the invisible. Their task: merge data from the Landsat satellite with the gritty reality of desert warfare depicted on military maps.
Brad Doorn, then a U.S. Army officer, sits at his desk during his early career in remote sensing. His military experience would later shape his work at NASA, applying satellite technology to real-world challenges. Credit: B. Doorn Landsat, a civilian satellite built by NASA and operated by the U.S. Geological Survey, could see what the soldiers on the ground could not. Its thermal infrared sensor—a camera with a penchant for temperature and moisture—read the desert floor like an ancient script, picking out the cold, soggy signature of mud lurking beneath the desert’s deceptive crust. Each pixel of satellite data became a brushstroke in a new kind of map, keeping tanks out of the mire and the missions on track.
“It was so neat to see the remote sensing techniques I’d learned about in school actually making a difference,” Doorn said.
With this knowledge, he helped guide his unit’s shift from analog maps—paper grids and grease pencils—to the emerging world of digital mapping, a leap that sharpened the military’s ability to read the landscape and steer clear of trouble.
From Desert Muck to Farm Fields
Brad’s military experience gave him an early look at how satellite data could address tangible, on-the-ground challenges. In the Army, he saw how integrating satellite data into military maps could offer soldiers critical information. That experience set the foundation for his later work at NASA, where he would help develop technology with lasting, practical impacts.
Consider OpenET, a NASA-funded initiative that uses Landsat data to give farmers insights into water use and irrigation needs at field scale. The ET in OpenET stands not for the little alien who phoned home, but for evapotranspiration. It’s a combination of water evaporating from the ground and water released by plants into the air.
The program relies on the same thermal technology Doorn used during the Gulf War. Just as cooler, wetter areas in the desert hint at muddy spots, cooler patches in farm fields show where there’s more moisture or plants are releasing more water. These data are key to managing water resources wisely and keeping crops healthy.
“OpenET has transformed our understanding of water demand,” explained Doorn.
To better manage water, state officials and farmers in California are using satellite data through OpenET to track evapotranspiration. Here, the colors represent total evapotranspiration for 2023 as the equivalent depth of water in millimeters. Dark blue regions have higher evapotranspiration rates, such as in the Central Valley. Credit: NASA Earth Observatory using openetdata.org In the late 2000s, when a new generation of Landsat satellites was being planned, the thermal infrared imagers were initially left off the drawing board. “Landsat 8’s design caused a lot of consternation in some Western states that were beginning to use the instrument for measuring and monitoring water use,” said Tony Willardson, the executive director of the Western States Water Council, a government entity that advises western governors on water policy.
Brad played a key role in conveying to NASA the critical need for this technology, both for agriculture and water management, Willardson said. The thermal imager was eventually reinstated and has since “helped to close a gap in western water management.”
“A lot of the technologies that we are using more and more were developed by NASA,” said Willardson. “We need NASA to be doing even more in Earth science.”
Sowing Global Food Stability from Space
Brad ended up serving in the Army for nearly a decade. “You hit that 10-year mark in the military, and you sort of have to decide if you’re staying in for 20 or if you’re getting out,” said Brad. “My wife, Kristen, was able to manage her career as a registered dietician through the first four moves in six years, but eventually it was too much. So, I told her: ‘Your choice. You decide where we go next.’”
She chose southern Pennsylvania to be closer to her family. Brad was 32 years old, and the couple had two small children at the time—one of whom had had open-heart surgery at 6 weeks old to fix a heart defect. They would go on to have another child.
In the late 1990s, within a few years of leaving the military, Doorn found himself someplace he had never imagined: sitting behind a desk at the U.S. Department of Agriculture. For a boy who had grown up driving trucks across the plains of South Dakota—who had vowed never to work in an office, much less live east of the Mississippi—this was an unexpected detour. But he had long since learned that the best paths are often the ones you don’t see coming.
At USDA, he moved forward not with a grand plan, but with an instinctive trust in where curiosity and challenge might lead. He rose through the ranks, from a programmer to directing the agency’s international food production analysis program. He was increasingly driven by a conviction that satellite data, if used the right way, could transform how we see the land and the way we feed the world.
While at USDA, and later at NASA, which he joined in 2009, Brad was instrumental in developing and overseeing the Global Agricultural Monitoring (GLAM) system. This real-time interactive satellite platform delivers massive amounts of ready-to-use satellite data directly to USDA crop analysts, eliminating the burden of data processing and enabling them to focus on rapid crop analysis across the globe. It was a pioneering tool, said Inbal Becker-Reshef, a research professor at University of Maryland’s Department of Geographical Sciences, who played a central role in developing the GLAM system.
At a 2022 Kansas gathering, Brad Doorn presents to farmers about NASA’s Earth Science Division and its activities supporting agriculture. Credit: A. Whitcraft GLAM set the stage for GEOGLAM, a separate, international initiative launched in 2011 by agriculture ministers from the G20—a group of the world’s major economies—partly as a response to global food price volatility. GEOGLAM, which stands for Group on Earth Observations Global Agricultural Monitoring, uses satellite data to monitor global crop conditions, from drought stress to excessive rain, around the world.
Joseph Glauber, a former USDA chief economist, noted that there was initial uncertainty within USDA about the initiative’s longevity, but he credited Brad’s background with rallying support. Today, GEOGLAM’s monthly crop assessments, produced by over 40 organizations including USDA and NASA, serve as a global consensus on crop conditions, helping governments and humanitarian organizations anticipate food shortages.
“Even today, the G20 points to GEOGLAM and its sister initiative, the Agricultural Market Information System—which tracks how crop conditions affect markets—as major successes,” Glauber said.
Harvesting Data Amid Conflict
Doorn’s work crosses continents. When war broke out between Russia and Ukraine in 2022, it rattled global food markets. The Ukrainian government turned to NASA Harvest—a global food security and agriculture consortium led by the University of Maryland and funded by NASA—for help. As manager of NASA’s agriculture program, Brad was a driving force behind the launch of NASA Harvest in 2017, envisioning it as a program that would harness satellite data to provide timely, actionable insights for global agriculture.
From orbit, satellites could observe the sown and the harvested wheat, sunflowers, and barley, offering some of the only reliable estimates for fields in the war zone. Satellite imagery revealed that, despite the conflict, more cropland had been planted and harvested in Ukraine than anyone had expected, a finding that helped stabilize volatile global food prices.
“Brad and the team recognized that providing that type of rapid agricultural assessment for policy support is what NASA Harvest exists for,” said Becker-Reshef, who is the director of the consortium.
NASA Harvest’s reach stretches well beyond Europe. In sub-Saharan Africa, the consortium collaborates with local and international partners, tracking the health of crops and the creeping spread of drought. This information helps equip governments, aid organizations, and farmers to act before disaster strikes, making each data point a crucial defense against hunger.
NASA Harvest has since been joined by NASA Acres, founded in 2023 to provide satellite data and tools that help farmers make well-informed decisions for healthier crops and soil in the United States. One project, for example, involves working with farmers in Illinois to manage nitrogen use more effectively, leveraging satellite data to enhance crop yields while reducing environmental impact.
This image shows corn cultivation patterns across the U.S. Midwest in 2020, with lands planted in corn marked in yellow. The map was built from the Cropland Data Layer product provided by the National Agricultural Statistics Service, which includes data from the USGS National Land Cover Database and from satellites such as Landsat 8. Credit: NASA Earth Observatory/ Lauren Dauphin Friedl noted that Doorn understands the missions of both NASA and the USDA, and with his agricultural roots, he knows the needs of farmers and agricultural businesses firsthand. “Often in meetings, Brad would remind us that the margins for a farmer are in the pennies,” Friedl said. “They wouldn’t be able to afford remote sensing,” so making sure NASA’s satellite information was free and accessible was that much more important.
“It’s hard to imagine that NASA would have the agriculture program it does without somebody like Brad continuing to advocate and push for this to exist,” said Alyssa Whitcraft, the director of NASA Acres. “He knows how critical it is for satellite data to be accessible and useful to those on the ground. He makes sure we never lose sight of that.”
An Emissary Between Worlds
Colleagues say Doorn’s strength lies in his ability to bridge worlds, whether it’s making connections between agencies like NASA and USDA, or connecting such agencies to state water councils or farming communities. His fluency in translating complex science into simple terms makes him equally at ease in whichever world he finds himself.
“There’s NASA language and there’s farm language,” says Lance Lillibridge, who farms about 1,400 acres of corn and soybeans in Benton County, Iowa, and has helped lead the Iowa Corn Growers Association. “Sometimes you need an interpreter, and Brad’s that guy.” He recalled a meeting where some farmers were skeptical, wary of NASA’s “big brother” eyes in the sky, “but Brad had a way of putting people at ease, keeping everyone focused on the shared goal of better data for better decisions.”
Brad Doorn speaks during NASA’s “Space for Ag” roadshow in Iowa, July 2023, highlighting NASA’s role in supporting sustainable farming practices. Credit: N. Pepper “One of my favorite memories of Brad,” said Forrest Melton, the OpenET project scientist at NASA’s Ames Research Center, “is an afternoon spent visiting with farmers in western Nebraska, drinking iced tea and talking with them about the challenges facing their family farm.”
Colleagues describe Brad as a nearly unflappable guide, one who knows the agricultural landscape so well that he makes the impossible seem manageable. They say his calm, approachable style, paired with a ready smile, puts people at ease whether in Washington conference rooms or Midwestern barns. And he listens closely to understand where there may be opportunities to help.
“Few people in the water and agriculture communities, from the small-scale farmer to the federal government appointee, aren’t familiar with some aspect of the work Brad has enabled over the decades,” said Sarah Brennan, a former deputy program manager for NASA’s water resources programs. “He has supported the development of some of the greatest advancements in using remote sensing in these communities.”
It’s About the People and the Team
Doorn’s leadership is less about issuing directives, colleagues say, and more about cultivating growth—in crops, in data systems, and in people. Like a farmer tending to his fields, he nurtures the potential in every project and person he encounters. “Almost everyone who has worked for Brad can point back to the opportunities he provided them that launched their successful careers,” said Brennan.
Over the years, he’s added layers to this work of creating paths for others to succeed: as president of the American Society of Photogrammetry and Remote Sensing, as an adjunct professor at Penn State, and as a youth basketball league director.
“What I’ve learned, probably in the military and I’ve carried it forward, is that it’s the people that matter,” Brad said. “I had great mentors who believed it’s just as important to help others grow as it is to meet the day’s demands. Those roles shift your focus toward the people around you, and often, the more you give of your time, the more you end up getting back.”
Young Brad Doorn (front center) stands with his siblings, capturing a family moment in 1960s South Dakota. His youngest brother isn’t pictured. Credit: B. Doorn It has been a long journey from hauling milk and animal feed across the South Dakota plains to surveying them now as a scientist. The tools of his career have changed—from truck routes to satellite orbits, from paper maps to digital data—but his mission remains the same: helping farmers feed the world.
“Growing up in South Dakota, I saw firsthand the challenges farmers face. Today, I’m proud to help provide the tools and data that can make a real difference in their lives,” Doorn added. “Whether it’s a farmer, an economist, or a military analyst, if you give them the right tools, they’ll take them to places you never even thought about. That’s what excites me—seeing where they go.”
By Emily DeMarco
NASA’s Earth Science Division, Headquarters
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Last Updated Nov 20, 2024 Related Terms
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By European Space Agency
The two CubeSat passengers aboard ESA’s Hera mission for planetary defence have exchanged their first signals with Earth, confirming their nominal status. The pair were switched on to check out all their systems, marking the first operation of ESA CubeSats in deep space.
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