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2 Min Read Why NASA Is a Great Place to Launch Your Career
Students at NASA's Jet Propulsion Laboratory pose for photos around the laboratory wearing their eclipse glasses. Credits: NASA/JPL-Caltech Recently recognized as the most prestigious internship program by Vault.com, NASA has empowered countless students and early-career professionals to launch careers in science, technology, engineering, and mathematics (STEM) fields. NASA interns make real contributions to space and science missions, making it one of the best places to start your career.
“NASA internships give students the chance to work on groundbreaking projects alongside experts, providing impactful opportunities for professional growth,” said Mike Kincaid, associate administrator for NASA’s Office of STEM Engagement. “Since starting my career as an intern at NASA’s Johnson Space Center in Houston, I’ve experienced firsthand how NASA creates lasting connections and open doors—not just for me, but for former interns who are now colleagues across the agency. These internships build STEM skills, confidence, and networks, preparing the next generation of innovators and leaders.”
NASA interns achieve impressive feats, from discovering new exoplanets to becoming astronauts and even winning Webby Awards for their science communication efforts. These valuable contributors play a crucial role in NASA’s mission to explore the unknown for the benefit of all. Many NASA employees start their careers as interns, a testament to the program’s lasting impact.
Students congratulate the 23rd astronaut class at NASA’s Johnson Space Center in Houston on March 5, 2024.NASA/Josh Valcarcel Additionally, NASA is recognized as one of America’s Best Employers for Women and one of America’s Best Employers for New Graduates by Forbes, reflecting the agency’s commitment to fostering a diverse and inclusive environment. NASA encourages people from underrepresented groups to apply, creating a diverse cohort of interns who bring a wide range of perspectives and ideas to the agency.
“My internship experience has been incredible. I have felt welcomed by everyone I’ve worked with, which has been so helpful as a Navajo woman as I’ve often felt like an outsider in male-dominated STEM spaces,” said Tara Roanhorse, an intern for NASA’s Office of STEM Engagement.
If you’re passionate about space, technology, and making a difference in the world, NASA’s internship program is the perfect place to begin your journey toward a fulfilling and impactful career.
To learn more about NASA’s internship programs, visit: https://www.intern.nasa.gov/
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By NASA
Hubble Space Telescope Home NASA’s Hubble Finds… Hubble Space Telescope Hubble Home Overview About Hubble The History of Hubble Hubble Timeline Why Have a Telescope in Space? Hubble by the Numbers At the Museum FAQs Impact & Benefits Hubble’s Impact & Benefits Science Impacts Cultural Impact Technology Benefits Impact on Human Spaceflight Astro Community Impacts Science Hubble Science Science Themes Science Highlights Science Behind Discoveries Hubble’s Partners in Science Universe Uncovered Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts News Hubble News Hubble News Archive Social Media Media Resources Multimedia Multimedia Images Videos Sonifications Podcasts E-books Lithographs Fact Sheets Glossary Posters Hubble on the NASA App More Online Activities 5 Min Read NASA’s Hubble Finds Sizzling Details About Young Star FU Orionis
An artist’s concept of the early stages of the young star FU Orionis (FU Ori) outburst, surrounded by a disk of material. Credits:
NASA-JPL, Caltech In 1936, astronomers saw a puzzling event in the constellation Orion: the young star FU Orionis (FU Ori) became a hundred times brighter in a matter of months. At its peak, FU Ori was intrinsically 100 times brighter than our Sun. Unlike an exploding star though, it has declined in luminosity only languidly since then.
Now, a team of astronomers has wielded NASA’s Hubble Space Telescope‘s ultraviolet capabilities to learn more about the interaction between FU Ori’s stellar surface and the accretion disk that has been dumping gas onto the growing star for nearly 90 years. They find that the inner disk touching the star is extraordinarily hot — which challenges conventional wisdom.
The observations were made with the telescope’s COS (Cosmic Origins Spectrograph) and STIS (Space Telescope Imaging Spectrograph) instruments. The data includes the first far-ultraviolet and new near-ultraviolet spectra of FU Ori.
“We were hoping to validate the hottest part of the accretion disk model, to determine its maximum temperature, by measuring closer to the inner edge of the accretion disk than ever before,” said Lynne Hillenbrand of Caltech in Pasadena, California, and a co-author of the paper. “I think there was some hope that we would see something extra, like the interface between the star and its disk, but we were certainly not expecting it. The fact we saw so much extra — it was much brighter in the ultraviolet than we predicted — that was the big surprise.”
A Better Understanding of Stellar Accretion
Originally deemed to be a unique case among stars, FU Ori exemplifies a class of young, eruptive stars that undergo dramatic changes in brightness. These objects are a subset of classical T Tauri stars, which are newly forming stars that are building up by accreting material from their disk and the surrounding nebula. In classical T Tauri stars, the disk does not touch the star directly because it is restricted by the outward pressure of the star’s magnetic field.
The accretion disks around FU Ori objects, however, are susceptible to instabilities due to their enormous mass relative to the central star, interactions with a binary companion, or infalling material. Such instability means the mass accretion rate can change dramatically. The increased pace disrupts the delicate balance between the stellar magnetic field and the inner edge of the disk, leading to material moving closer in and eventually touching the star’s surface.
This is an artist’s concept of the early stages of the young star FU Orionis (FU Ori) outburst, surrounded by a disk of material. A team of astronomers has used the Hubble Space Telescope’s ultraviolet capabilities to learn more about the interaction between FU Ori’s stellar surface and the accretion disk that has been dumping gas onto the growing star for nearly 90 years. They found that the inner disk, touching the star, is much hotter than expected—16,000 kelvins—nearly three times our Sun’s surface temperature. That sizzling temperature is nearly twice as hot as previously believed. NASA-JPL, Caltech
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The enhanced infall rate and proximity of the accretion disk to the star make FU Ori objects much brighter than a typical T Tauri star. In fact, during an outburst, the star itself is outshined by the disk. Furthermore, the disk material is orbiting rapidly as it approaches the star, much faster than the rotation rate of the stellar surface. This means that there should be a region where the disk impacts the star and the material slows down and heats up significantly.
“The Hubble data indicates a much hotter impact region than models have previously predicted,” said Adolfo Carvalho of Caltech and lead author of the study. “In FU Ori, the temperature is 16,000 kelvins [nearly three times our Sun’s surface temperature]. That sizzling temperature is almost twice the amount prior models have calculated. It challenges and encourages us to think of how such a jump in temperature can be explained.”
To address the significant difference in temperature between past models and the recent Hubble observations, the team offers a revised interpretation of the geometry within FU Ori’s inner region: The accretion disk’s material approaches the star and once it reaches the stellar surface, a hot shock is produced, which emits a lot of ultraviolet light.
Planet Survival Around FU Ori
Understanding the mechanisms of FU Ori’s rapid accretion process relates more broadly to ideas of planet formation and survival.
“Our revised model based on the Hubble data is not strictly bad news for planet evolution, it’s sort of a mixed bag,” explained Carvalho. “If the planet is far out in the disk as it’s forming, outbursts from an FU Ori object should influence what kind of chemicals the planet will ultimately inherit. But if a forming planet is very close to the star, then it’s a slightly different story. Within a couple outbursts, any planets that are forming very close to the star can rapidly move inward and eventually merge with it. You could lose, or at least completely fry, rocky planets forming close to such a star.”
Additional work with the Hubble UV observations is in progress. The team is carefully analyzing the various spectral emission lines from multiple elements present in the COS spectrum. This should provide further clues on FU Ori’s environment, such as the kinematics of inflowing and outflowing gas within the inner region.
“A lot of these young stars are spectroscopically very rich at far ultraviolet wavelengths,” reflected Hillenbrand. “A combination of Hubble, its size and wavelength coverage, as well as FU Ori’s fortunate circumstances, let us see further down into the engine of this fascinating star-type than ever before.”
These findings have been published in The Astrophysical Journal Letters.
The observations were taken as part of General Observer program 17176.
The Hubble Space Telescope has been operating for over three decades and continues to make ground-breaking discoveries that shape our fundamental understanding of the universe. Hubble is a project of international cooperation between NASA and ESA (European Space Agency). NASA’s Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope and mission operations. Lockheed Martin Space, based in Denver, also supports mission operations at Goddard. The Space Telescope Science Institute in Baltimore, which is operated by the Association of Universities for Research in Astronomy, conducts Hubble science operations for NASA.
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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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5 Min Read Making Mars’ Moons: Supercomputers Offer ‘Disruptive’ New Explanation
A NASA study using a series of supercomputer simulations reveals a potential new solution to a longstanding Martian mystery: How did Mars get its moons? The first step, the findings say, may have involved the destruction of an asteroid.
The research team, led by Jacob Kegerreis, a postdoctoral research scientist at NASA’s Ames Research Center in California’s Silicon Valley, found that an asteroid passing near Mars could have been disrupted – a nice way of saying “ripped apart” – by the Red Planet’s strong gravitational pull.
The team’s simulations show the resulting rocky fragments being strewn into a variety of orbits around Mars. More than half the fragments would have escaped the Mars system, but others would’ve stayed in orbit. Tugged by the gravity of both Mars and the Sun, in the simulations some of the remaining asteroid pieces are set on paths to collide with one another, every encounter further grinding them down and spreading more debris.
Many collisions later, smaller chunks and debris from the former asteroid could have settled into a disk encircling the planet. Over time, some of this material is likely to have clumped together, possibly forming Mars’ two small moons, Phobos and Deimos.
To assess whether this was a realistic chain of events, the research team explored hundreds of different close encounter simulations, varying the asteroid’s size, spin, speed, and distance at its closest approach to the planet. The team used their high-performance, open-source computing code, called SWIFT, and the advanced computing systems at Durham University in the United Kingdom to study in detail both the initial disruption and, using another code, the subsequent orbits of the debris.
In a paper published Nov. 20 in the journal Icarus, the researchers report that, in many of the scenarios, enough asteroid fragments survive and collide in orbit to serve as raw material to form the moons.
“It’s exciting to explore a new option for the making of Phobos and Deimos – the only moons in our solar system that orbit a rocky planet besides Earth’s,” said Kegerreis. “Furthermore, this new model makes different predictions about the moons’ properties that can be tested against the standard ideas for this key event in Mars’ history.”
Two hypotheses for the formation of the Martian moons have led the pack. One proposes that passing asteroids were captured whole by Mars’ gravity, which could explain the moons’ somewhat asteroid-like appearance. The other says that a giant impact on the planet blasted out enough material – a mix of Mars and impactor debris – to form a disk and, ultimately, the moons. Scientists believe a similar process formed Earth’s Moon.
The latter explanation better accounts for the paths the moons travel today – in near-circular orbits that closely align with Mars’ equator. However, a giant impact ejects material into a disk that, mostly, stays close to the planet. And Mars’ moons, especially Deimos, sit quite far away from the planet and probably formed out there, too.
“Our idea allows for a more efficient distribution of moon-making material to the outer regions of the disk,” said Jack Lissauer, a research scientist at Ames and co-author on the paper. “That means a much smaller ‘parent’ asteroid could still deliver enough material to send the moons’ building blocks to the right place.”
It’s exciting to explore a new option for the making of Phobos and Deimos – the only moons in our solar system that orbit a rocky planet besides Earth’s.
Jacob Kegerreis
Postdoctoral research scientist at NASA’s Ames Research Center
Testing different ideas for the formation of Mars’ moons is the primary goal of the upcoming Martian Moons eXploration (MMX) sample return mission led by JAXA (Japan Aerospace Exploration Agency). The spacecraft will survey both moons to determine their origin and collect samples of Phobos to bring to Earth for study. A NASA instrument on board, called MEGANE – short for Mars-moon Exploration with GAmma rays and Neutrons – will identify the chemical elements Phobos is made of and help select sites for the sample collection. Some of the samples will be collected by a pneumatic sampler also provided by NASA as a technology demonstration contribution to the mission. Understanding what the moons are made of is one clue that could help distinguish between the moons having an asteroid origin or a planet-plus-impactor source.
Before scientists can get their hands on a piece of Phobos to analyze, Kegerreis and his team will pick up where they left off demonstrating the formation of a disk that has enough material to make Phobos and Deimos.
“Next, we hope to build on this proof-of-concept project to simulate and study in greater detail the full timeline of formation,” said Vincent Eke, associate professor at the Institute for Computational Cosmology at Durham University and a co-author on the paper. “This will allow us to examine the structure of the disk itself and make more detailed predictions for what the MMX mission could find.”
For Kegerreis, this work is exciting because it also expands our understanding of how moons might be born – even if it turns out that Mars’ own formed by a different route. The simulations offer a fascinating exploration, he says, of the possible outcomes of encounters between objects like asteroids and planets. These events were common in the early solar system, and simulations could help researchers reconstruct the story of how our cosmic backyard evolved.
This research is a collaborative effort between Ames and Durham University, supported by the Institute for Computational Cosmology’s Planetary Giant Impact Research group. The simulations used were run using the open-source SWIFT code, carried out on the DiRAC (Distributed Research Utilizing Advanced Computing) Memory Intensive service (“COSMA”), hosted by Durham University on behalf of the DiRAC High-Performance Computing facility.
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By NASA
5 min read
NASA’s Swift Reaches 20th Anniversary in Improved Pointing Mode
After two decades in space, NASA’s Neil Gehrels Swift Observatory is performing better than ever thanks to a new operational strategy implemented earlier this year. The spacecraft has made great scientific strides in the years since scientists dreamed up a new way to explore gamma-ray bursts, the most powerful explosions in the universe.
“The idea for Swift was born during a meeting in a hotel basement in Estes Park, Colorado, in the middle of a conference,” said John Nousek, the Swift mission director at Pennsylvania State University in State College. “A bunch of astrophysicists got together to brainstorm a mission that could help us solve the problem of gamma-ray bursts, which were a very big mystery at the time.”
Watch to learn how NASA’s Neil Gehrels Swift Observatory got its name.
NASA’s Goddard Space Flight Center Gamma-ray bursts occur all over the sky without warning, with about one a day detected on average. Astronomers generally divide these bursts into two categories. Long bursts produce an initial pulse of gamma rays for two seconds or more and occur when the cores of massive stars collapse to form black holes. Short bursts last less than two seconds and are caused by the mergers of dense objects like neutron stars.
But in 1997, at the time of that basement meeting, the science community disagreed over the origin models for these events. Astronomers needed a satellite that could move quickly to locate them and move to point additional instruments at their positions.
What developed was Swift, which launched Nov. 20, 2004, from Complex 17A at what is now Cape Canaveral Space Force Station in Florida. Originally called the Swift Observatory for its ability to quickly point at cosmic events, the mission team renamed the spacecraft in 2018 after its first principal investigator Neil Gehrels.
Swift uses several methods for orienting and stabilizing itself in space to study gamma-ray bursts.
Sensors that detect the Sun’s location and the direction of Earth’s magnetic field provide the spacecraft with a general sense of its location. Then, a device called a star tracker looks at stars and tells the spacecraft how to maneuver to keep the observatory precisely pointed at the same position during long observations.
Swift uses three spinning gyroscopes, or gyros, to carry out those moves along three axes. The gyros were designed to align at right angles to each other, but once in orbit the mission team discovered they were slightly misaligned. The flight operations team developed a strategy where one of the gyros worked to correct the misalignment while the other two pointed Swift to achieve its science goals.
The team wanted to be ready in case one of the gyros failed, however, so in 2009 they developed a plan to operate Swift using just two.
Swift orbits above Earth in this artist’s concept. NASA’s Goddard Space Flight Center Conceptual Image Lab Any change to the way a telescope operates once in space carries risk, however. Since Swift was working well, the team sat on their plan for 15 years.
Then, in July 2023, one of Swift’s gyros began working improperly. Because the telescope couldn’t hold its pointing position accurately, observations got progressively blurrier until the gyro failed entirely in March 2024.
“Because we already had the shift to two gyros planned out, we were able to quickly and thoroughly test the procedure here on the ground before implementing it on the spacecraft,” said Mark Hilliard, Swift’s flight operations team lead at Omitron, Inc. and Penn State. “Actually, scientists have commented that the accuracy of Swift’s pointing is now better than it was since launch, which is really encouraging.”
For the last 20 years, Swift has contributed to groundbreaking results — not only for gamma-ray bursts but also for black holes, stars, comets, and other cosmic objects.
“After all this time, Swift remains a crucial part of NASA’s fleet,” said S. Bradley Cenko, Swift’s principal investigator at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “The satellite’s abilities have helped pioneer a new era of astrophysics called multimessenger astronomy, which is giving us a more well-rounded view of how the universe works. We’re looking forward to all Swift has left to teach us.”
Swift is a key part of NASA’s strategy to look for fleeting and unpredictable changes in the sky with a variety of telescopes that use different methods of studying the cosmos.
Goddard manages the Swift mission in collaboration with Penn State, the Los Alamos National Laboratory in New Mexico, and Northrop Grumman Space Systems in Dulles, Virginia. Other partners include the University of Leicester and Mullard Space Science Laboratory in the United Kingdom, Brera Observatory in Italy, and the Italian Space Agency.
Download high-resolution images on NASA’s Scientific Visualization Studio
By Jeanette Kazmierczak
NASA’s Goddard Space Flight Center, Greenbelt, Md.
Media Contact:
Claire Andreoli
301-286-1940
claire.andreoli@nasa.gov
NASA’s Goddard Space Flight Center, Greenbelt, Md.
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Last Updated Nov 20, 2024 Editor Jeanette Kazmierczak Location Goddard Space Flight Center Related Terms
Astrophysics Gamma-Ray Bursts Goddard Space Flight Center Neil Gehrels Swift Observatory The Universe View the full article
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