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By NASA
Dr. Steven “Steve” Platnick stepped down from his role at NASA on August 8, 2025, after more than three decades of public service. Steve began his career at NASA as a physical scientist at Goddard Space Flight Center in 2002. He moved to the Earth Science Division in 2009, where he has served in various senior management roles, including as the Earth Observing System (EOS) Senior Project Scientist. In this role, he led the EOS Project Science Office and continued periodic meetings of the EOS Project Scientists, initiated by Michael King during his tenure. Steve expanded these meetings to include representatives of non-EOS Earth observing missions and representatives from Earth Science Mission Operations (ESMO). In addition, Steve was named Deputy Director for Atmospheres in the Earth Science Division in January 2015 and served in this position until July 2024.
Dr. Steve Platnick Image credit: NASA During his time at NASA, Steve played an integral role in the development, sustainability, and advancement of NASA’s Earth Observing System platforms. From January 2003 – February 2010, Steve served as Deputy Project Scientist for Aqua. In this role, he applied his expertise in theoretical and experimental studies of satellite, aircraft, and ground-based cloud remote sensing to improve algorithms to benefit the data gathered from remote observing systems.
Taking the Lead to Improve Algorithms
Steve was actively involved in the Moderate Resolution Imaging Spectroradiometer (MODIS) Science Team, serving as the MODIS Atmosphere Team Lead. Steve helped advance several key components of the MODIS instrument, which flies on NASA’s Terra and Aqua platforms. He led a team that enhanced, maintained, and evaluated MODIS algorithms that support the Level-2 (L2) Cloud Optical/Microphysical Properties components (e.g., COD06 and MYD06) for MODIS on Terra and Aqua. The algorithms were designed to retrieve thermodynamic phase, optical thickness, effective particle radius, and water path for liquid and ice clouds. The team’s work also contributes to L3 products that address cloud mask, aerosols, clouds, and clear sky radiance for data within 1° grids over one-day, eight-day, and one-month repeat cycles. Under Steve’s leadership, the team also developed L2 products (e.g., MODATML2 and MYDATML2) that include essential atmosphere datasets of samples collected at 5–10 km (3–6 mi) that is consistent with L3 products to ease storage requirements of core atmospheric data.
Steve is also a member of the Suomi-National Polar-orbiting Partnership (Suomi NPP) Atmosphere Team, working on operational cloud optical and microphysical products. In this role, he contributed to algorithm development and refinement for the Cloud Product. In particular, he helped address a critical gap in the Visible Infrared Imaging Radiometer Suite (VIIRS) spectral channel, which was not designed to collect information for carbon dioxide (CO2) slicing and water vapor data in the same way as MODIS. Steve and his colleagues developed a suite of L2 algorithms for the spectral channels that were common to both MODIS and VIIRS to address cloud mask and cloud optical/microphysical properties. Through these efforts, the project has established a continuous cloud data record gathered from both instruments from 2017 to the present.
Steve also participated in numerous other working groups during the past 30 years. He participated in the Global Energy and Water Exchanges (GEWEX) Cloud Assessment Working Group (2008–present), Arctic Radiation-Cloud-Aerosol-Surface Interaction Experiment (ARCSIX) Science Team (2023–present), ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES) Earth–Venture Suborbital (EVS)-2 Science Team (2014–2023), Deep Space Climate Observatory (DSCOVR) Science Team (2014–present), Plankton, Aerosol, Cloud, ocean Ecosystem (PACE) Science Team (2014–2023), PACE Science Definition Team, Deputy Chair (2011–2012), Glory Science Team (2010–2014) NASA Observations for Modeling Intercomparison Studies (obs4MIPs) Working Group (2011), Advanced Composition Explorer (ACE) Science Definition Team (2009–2011), and Geostationary Operational Environmental Satellites (GOES) R-series Advanced Baseline Imager (ABI) Cloud Team (2005–2009).
Steve has also participated in numerous major airborne field campaigns in various roles, including: GSFC Lidar Observation and Validation Experiment (GLOVE, 2025), PACE Postlaunch Airborne eXperiment (PAX, 2024), the Westcoast & Heartland Hyperspectral Microwave Sensor Intensive Experiment (WH2yMSIE, 2024), ORACLES Science Team (2015–2019), Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) Science Team (2011–2015), Tropical Composition, Cloud and Climate Coupling (TC4) Management Team (2007), Cirrus Regional Study of Tropical Anvils and Cirrus Layers – Florida Area Cirrus Experiment (CRYSTAL-FACE) Science Management Team (2002), Southern Africa Fire-Atmosphere Research Initiative (SAFARI, 2000), First ISCCP Regional Experiment (FIRE) Arctic Cloud Experiment (ACE) (1998), Mikulski Archive for Space Telescopes (MAST, 1994), and ACE (1992).
Supporting Earth Science Communications
Through his senior leadership roles within ESD Steve has been supportive of the activities of NASA’s Science Support Office (SSO). He has participated in many NASA Science exhibits at both national and international scientific conferences, including serving as a Hyperwall presenter numerous times. He has met with task leaders frequently and has advocated on behalf of the SSO to management at NASA Headquarters, GSFC, and Global Sciences & Technology Inc.
For The Earth Observer newsletter publication team in particular, Steve replaced Michael King as Acting EOS Senior Project Scientist in June 2008, taking over the authorship of “The Editor’s Corner” beginning with the May–June 2008 issue [Volume 20, Issue 3]. The Acting label was removed beginning with the January–February 2010 issue [Volume 22, Issue 1]. Steve has been a champion of continuing to retain a historical record of NASA meetings to maintain a chronology of advances made by different groups within the NASA Earth Science community. He was supportive of the Executive Editor’s efforts to create a series called “Perspectives on EOS,” which ran from 2008–2011 and told the stories of the early years of the EOS Program from the point of view of those who lived them. He also supported the development of articles to commemorate the 25th and 30th anniversary of The Earth Observer. Later, Steve helped guide the transition of the newsletterfrom a print publication – the November–December 2022 issue was the last printed issue – to fully online by July 2024, a few months after the publication’s 35th anniversary. The Earth Observer team will miss Steve’s keen insight, historical perspective, and encouragement that he has shown through his leadership for the past 85 issues of print and online publications.
A Career Recognized through Awards and Honors
Throughout his career, Steve has amassed numerous honors, including the Robert H. Goddard Award for Science: MODIS/VIIRS Cloud Products Science Team (2024) and the William Nordberg Memorial Award for Earth Science in 2023. He received the Verner E. Suomi Award from the American Meteorological Society (AMS) in 2016 and was named an AMS Fellow that same year.
Steve has received numerous NASA Group Achievement Awards, including for the Cloud, Aerosol and Monsoon Processes Philippines Experiment (CAMP2Ex) Field Campaign Team (2020), Fire Influence of Regional to Global Environments and Air Quality (FIREX-AQ) Field Campaign Team (2020), ORACLES Field Campaign Team (2019), obs4MIPs Working Group (2015), SEAC4RS Field Campaign Team (2015), Advanced Microwave Scanning Radiometer for EOS (AMSR-E) Instrument Recovery Team (2013), Climate Absolute Radiance and Refractivity Observatory (CLARREO) Mission Concept Team (2012), Earth Science Constellation Red Team (2011), Science Mission Directorate ARRA Team (2011), TC4 Team (2009), MODIS Science Data Support Team (2007), Aqua Mission Team (2003), CRYSTAL-FACE Science Team (2003), and SAFARI 2000 International Leadership Team (2002).
Steve received two NASA Agency Honor Awards – the Exceptional Service Medal in 2015 and the Exceptional Achievement Medal in 2008. He was also part of the NASA Agency Team Excellence Award in 2017 for his work with the Satellite Needs Assessment Team. The Laboratory for Atmospheres honored him with the Best Senior Author Publication Award in 2001 and the Scientific Research Peer Award in 2005.
Steve received his bachelor’s degree and master’s degree in electrical engineering from Duke University and the University of California, Berkeley, respectively. He earned a Ph.D. in atmospheric sciences from the University of Arizona. He began his career at the Joint Center for Earth Systems Technology (JCET) at University of Maryland Baltimore County in 1996 as a research associate professor. He held this appointment until 2002. Steve has published more than 150 scholarly articles.
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By NASA
While it may sound like the opening to a punchline, this scientific question was at the heart of a research experiment that orbited the Moon aboard Artemis I.NASA astronaut and Expedition 65 Flight Engineer Mark Vande Hei caring for chili peppers aboard the International Space Station. NASA New research uncovers the connection between space agriculture and astronaut health. A study published in npj Microgravity shows how analyzing diverse datasets together can reveal insights that might otherwise be missed — in this case, linking space-grown food quality to astronaut nutrition and gut health.
The paper reviewed previous studies of plants grown aboard the International Space Station. The authors found that some edible plants grown in low Earth orbit have lower concentrations of essential nutrients, like calcium and magnesium, than those grown on Earth.
The reduced levels of these nutrients could make crops not as effective in mitigating the bone loss and reduced immune function that astronauts encounter in space.
Working Groups Uncover Hidden Health Connections
Three Analysis Working Groups from NASA’s Open Science Data Repository collaborated to make this paper possible. These discipline-specific groups typically work independently, but this project sparked conversations among researchers with different specialties.
Researchers combined plant data, crop nutrition profiles, gut studies, and astronaut blood biomarkers — a data integration effort of the Biological and Physical Sciences Division open science model. The work also draws on data from JAXA (Japan Aerospace Exploration Agency).
For NASA, these findings offer new insights into how to feed and support astronauts in space, particularly on long-duration missions to the Moon and Mars.
Seeks Ways to Improve Space Diets
The study also examined increased intestinal permeability — often called “leaky gut” — a condition that can result from poor nutrition and may be exacerbated by the space environment. Intestinal permeability may interfere with how astronauts absorb nutrients and regulate immune responses.
If properly engineered, space-grown crops could offer a solution to these health challenges. The team outlined several potential strategies, including bioengineering plants with higher nutrient content, incorporating more antioxidant-rich species, and designing personalized nutrition plans using astronauts’ genetic information.
The study suggests targeting specific biological pathways, such as using compounds like quercetin, an antioxidant found in certain crops, to address bone health challenges at the molecular level. The approach emphasizes designing nutrition plans based on individual astronaut physiology, including how well their digestive systems can absorb nutrients.
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NASA’s Biological and Physical Sciences Division pioneers scientific discovery and enables exploration by using space environments to conduct investigations not possible on Earth. Studying biological and physical phenomenon under extreme conditions allows researchers to advance the fundamental scientific knowledge required to go farther and stay longer in space, while also benefitting life on Earth.
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By NASA
5 min read
NASA’s Apollo Samples, LRO Help Scientists Predict Moonquakes
This mosaic of the Taurus-Littrow valley was made using images from the Narrow Angle Cameras onboard NASA’s Lunar Reconnaissance Orbiter. The orbiter has been circling and studying the Moon since 2009. The ancient-lava-filled valley is cut by the Lee-Lincoln thrust fault, visible as a sinuous, white line extending from South Massif (mountain in the bottom left corner) to North Massif (mountain in the top center) where the fault abruptly changes direction and cuts along the slope of North Massif. The Lee-Lincoln fault has been the source of multiple strong moonquakes causing landslides and boulder falls on both North and South massifs. The approximate location of the Apollo 17 landing site is indicated to the right of the fault with a white “x”. NASA/ASU/Smithsonian As NASA prepares to send astronauts to the surface of the Moon’s south polar region for the first time ever during the Artemis III mission, scientists are working on methods to determine the frequency of moonquakes along active faults there.
Faults are cracks in the Moon’s crust that indicate that the Moon is slowly shrinking as its interior cools over time. The contraction from shrinking causes the faults to move suddenly, which generates quakes. Between 1969 and 1977, a network of seismometers deployed by Apollo astronauts on the Moon’s surface recorded thousands of vibrations from moonquakes.
Moonquakes are rare, with the most powerful ones, about magnitude 5.0, occurring near the surface. These types of quakes are much weaker than powerful quakes on Earth (magnitude 7.0 or higher), posing little risk to astronauts during a mission lasting just a few days. But their effects on longer-term lunar surface assets could be significant. Unlike an earthquake that lasts for tens of seconds to minutes, a moonquake can last for hours, enough time to damage or tip over structures, destabilize launch vehicles on the surface, or interrupt surface operations.
“The hazard probability goes way up depending on how close your infrastructure is to an active fault,” said Thomas Watters, senior scientist emeritus at the Smithsonian’s National Air & Space Museum in Washington.
Watters is a long-time researcher of lunar geology and a co-investigator on NASA’s LRO (Lunar Reconnaissance Orbiter) camera. Recently, he and Nicholas Schmerr, a planetary seismologist at the University of Maryland in College Park, developed a new method for estimating the magnitude of seismic shaking by analyzing evidence of dislodged boulders and landslides in an area, as the scientists reported on July 30 in the journal Science Advances. Studies like these can help NASA plan lunar surface assets in safer locations.
Unlike an earthquake that lasts for tens of seconds to minutes, a moonquake can last for hours, enough time to damage or tip over structures, destabilize launch vehicles on the surface, or interrupt surface operations.
There are thousands of faults across the Moon that may still be active and producing quakes. Watters and his team have identified these faults by analyzing data from LRO, which has been circling the Moon since 2009, mapping the surface and taking pictures, providing unprecedented detail of features like faults, boulders, and landslides.
For this study, Watters and Schmerr chose to analyze surface changes from quakes generated by the Lee-Lincoln fault in the Taurus-Littrow valley. NASA’s Apollo 17 astronauts, who landed about 4 miles west of the fault on Dec. 11, 1972, explored the area around the fault during their mission.
By studying boulder falls and a landslide likely dislodged by ground shaking near Lee Lincoln, Watters and Schmerr estimated that a magnitude 3.0 moonquake — similar to a relatively minor earthquake — occurs along the Lee Lincoln fault about every 5.6 million years.
“One of the things we’re learning from the Lee-Lincoln fault is that many similar faults have likely had multiple quakes spread out over millions of years,” Schmerr said. “This means that they are potentially still active today and may keep generating more moonquakes in the future.”
The authors chose to study the Lee-Lincoln fault because it offered a unique advantage: Apollo 17 astronauts brought back samples of boulders from the area. By studying these samples in labs, scientists were able to measure changes in the boulders’ chemistry caused by exposure to cosmic radiation over time (the boulder surface is freshly exposed after breaking off a larger rock that would have otherwise shielded it).
This cosmic radiation exposure information helped the researchers determine how long the boulders had been sitting in their current locations, which in turn helped inform the estimate of possible timing and frequency of quakes along the Lee-Lincoln fault.
This 1972 image shows Apollo 17 astronaut Harrison H. Schmitt sampling a boulder at the base of North Massif in the Taurus-Littrow valley on the Moon. This large boulder is believed to have been dislodged by a strong moonquake that occurred about 28.5 million years ago. The source of the quake was likely a seismic event along the Lee-Lincoln fault. The picture was taken by astronaut Eugene A. Cernan, Apollo 17 commander. NASA/JSC/ASU Apollo 17 astronauts investigated the boulders at the bases of two mountains in the valley. The tracks left behind indicated that the boulders may have rolled downhill after being shaken loose during a moonquake on the fault. Using the size of each boulder, Watters and Schmerr estimated how hard the ground shaking would have been and the magnitude of the quake that would have caused the boulders to break free.
The team also estimated the seismic shaking and quake magnitude that would be needed to trigger the large landslide that sent material rushing across the valley floor, suggesting that this incident caused the rupture event that formed the Lee-Lincoln fault.
A computer simulation depicting the seismic waves emanating from a shallow moonquake on the Lee-Lincoln fault in the Taurus-Littrow valley on the Moon. The label “A17” marks the Apollo 17 landing site. The audio represents a moonquake that was recorded by a seismometer placed on the surface by astronauts. The seismic signal is converted into sound. Both audio and video are sped up to play 10 times faster than normal. The background image is a globe mosaic image from NASA’s Lunar Reconnaissance Orbiter’s Wide-Angle Camera. Red and blue are positive (upward ground motion) and negative (downward ground motion) polarities of the wave. Nicholas Schmerr Taking all these factors into account, Watters and Schmerr estimated that the chances that a quake would have shaken the Taurus-Littrow valley on any given day while the Apollo 17 astronauts were there are 1 in 20 million, the authors noted.
Their findings from the Lee-Lincoln fault are just the beginning. Watters and Schmerr now plan to use their new technique to analyze quake frequency at faults in the Moon’s south polar region, where NASA plans to explore.
NASA also is planning to send more seismometers to the Moon. First, the Farside Seismic Suite will deliver two sensitive seismometers to Schrödinger basin on the far side of the Moon onboard a lunar lander as part of NASA’s CLPS (Commercial Lunar Payload Services) initiative. Additionally, NASA is developing a payload, called the Lunar Environment Monitoring Station, for potential flight on NASA’s Artemis III mission to the South Pole region. Co-led by Schmerr, the payload will assess seismic risks for future human and robotic missions to the region.
Read More: What Are Moonquakes?
Read More: Moonquakes and Faults Near Lunar South Pole
For more information on NASA’s LRO, visit:
Media Contacts:
Karen Fox / Molly Wasser
Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov
Lonnie Shekhtman
NASA’s Goddard Space Flight Center, Greenbelt, Md.
lonnie.shekhtman@nasa.gov
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Last Updated Aug 14, 2025 Related Terms
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By NASA
NASA Honor Award recipients are shown with their award plaques, alongside NASA Stennis Space Center Director John Bailey and Deputy Director Christine Powell, following the ceremony at NASA Stennis on Aug. 13. Pictured (left to right) is Andrew Bracey, Briou Bourgeois, Jared Grover, Robert Simmers, Robert Williams, Richard Wear, Tom Stanley, Alison Dardar, Marvin Horne, Cary Tolman, Tim Pierce, Rebecca Mataya, Bailey, Powell, Gina Ladner, and Brittany Bouche. NASA/Danny Nowlin NASA Stennis Space Center Director John Bailey speaks to employees during the NASA Honor Awards ceremony at NASA Stennis on Aug. 13. NASA/Danny Nowlin NASA Stennis Space Center Director John Bailey and Deputy Director Christine Powell presented NASA Honor Awards to employees during an onsite ceremony Aug. 13.
One NASA Stennis employee received NASA’s Outstanding Leadership Medal. The medal is awarded to government employees for notable leadership accomplishments that have significantly influenced the NASA mission.
Marvin Horne of Fulton, Maryland, received the NASA Outstanding Leadership Medal for his work in the Office of Procurement that has resulted in significant cost savings for the agency. Among his accomplishments, Horne designed, implemented, and led an integrated contract management office between NASA Stennis, NASA’s Michoud Assembly Facility in New Orleans, and NASA’s Marshall Space Flight Center in Huntsville, Alabama. The office transformed facility services from independent models to a shared model. The innovative solution was the first joint contract management office at NASA Stennis comprised of procurement, finance, and technical personnel designed to implement effective and efficient business processes. Horne currently serves as the NASA acting administrator for procurement.
Three NASA Stennis employees received NASA’s Exceptional Service Medal. The medal is awarded to government employees for sustained performance that embodies multiple contributions to NASA projects, programs, or initiatives.
Jared Grover of Diamondhead, Mississippi, received the NASA Exceptional Service Medal for his contributions to the success of the NASA Stennis E Test Complex through his dedication and technical expertise. As a NASA mechanical operations engineer, he has led various testing and facility preparation efforts, worked with challenging propellants, and trained new personnel. His work has supported numerous NASA and commercial aerospace projects Grover is also active in community outreach, promoting NASA’s mission and inspiring future engineers.
Tim Pierce of Long Beach, Mississippi, received the NASA Exceptional Service Medal following 26 years with NASA and 41 years working at NASA Stennis as a contractor and civil servant in the Center Operations Directorate. Through Pierce’s contributions, NASA Stennis became a leader in drafting agreements with external agencies, streamlining administrative procedures, and enhancing partnerships. In one notable instance, he led efforts to collaborate with county officials on a sewer treatment project that will save costs and optimize underused infrastructure. Pierce retired from NASA in January 2025.
Barry Robinson of Slidell, Louisiana, received the NASA Exceptional Service Medal in absentia for service to the nation’s space program and achievement across multiple propulsion test programs and projects. Robinson joined NASA in 1994 and worked on the space shuttle main engine test project, eventually becoming a test operations consultant. Over the years, Robinson held various roles, including chief of the NASA Stennis Mechanical Engineering Branch and project manager for projects supporting NASA’s SLS (Space Launch System) rocket for Artemis missions to the Moon and beyond. Robinson retired from NASA in December 2024.
One NASA Stennis employee received NASA’s Exceptional Engineering Achievement Medal. The medal is awarded to both government and non-government individuals for exceptional engineering contributions toward achievement of NASA’s mission.
Richard Wear of Slidell, Louisiana, received the NASA Exceptional Engineering Achievement Medal for his contributions to the NASA Stennis Engineering and Test Directorate. Wear serves as the subject matter expert in thermal and fluid systems analysis. In that role, he has greatly contributed to facilitating the use of liquid natural gas propellant in testing onsite, including by developing a Cryogenics in Propulsion Testing training course to support future test projects and programs. His contributions have significantly enhanced NASA’s support for commercial partners at NASA Stennis.
Eight NASA Stennis employees received NASA’s Exceptional Achievement Medal. This medal is awarded to any government employee for a significant specific achievement or substantial improvement in operations, efficiency, service, financial savings, science, or technology which contributes to the mission of NASA.
Leslie Anderson of Picayune, Mississippi, received the NASA Exceptional Achievement Medal in absentia for leadership and customer service as the lead accountant in the Office of the Chief Financial Officer at NASA Stennis. Anderson has successfully managed critical financial activities with technical expertise, project management, and strong customer service skills. Her efforts help maintain federal partnerships worth approximately $70 million annually and contribute to the success of NASA Stennis, demonstrating NASA’s core values of integrity, teamwork, excellence, and inclusion.
Alison Dardar of Diamondhead, Mississippi, received the NASA Exceptional Achievement Medal for innovation in improving financial and technical processes associated with the $1 billion-plus consolidated operations and maintenance contract for NASA Stennis and NASA’s Michoud Assembly Facility in New Orleans. As senior budget analyst in the NASA Stennis Office of the Chief Financial Officer, Dardar led in identifying and addressing key reporting and accounting issues related to the contract. Her innovations resulted in a 55% improvement in cost reporting accuracy and $20 million in savings to the contract.
Gina Ladner of Diamondhead, Mississippi, received the NASA Exceptional Achievement Medal for management, problem solving, and leadership during a year-long detail as chief of the NASA Stennis Facilities Services Division. During the year, Ladner led the division team through numerous changes and tackled unexpected challenges, including a severe weather event that featured confirmed tornados onsite and a contractor work stoppage activity, to ensure ongoing site operations. She also led in numerous infrastructure investments, including repairs to roadways, fire systems, and communications equipment.
Rebecca Mataya of Carriere, Mississippi, received the NASA Exceptional Achievement Medal for service as a budget analyst in the NASA Stennis Office of the Chief Financial Officer in improving processes and operations. As an analyst on the procurement development team for a new operations, services, and infrastructure contract, Mataya identified creative methods to increase cost savings and maximize facility projects. She also has helped secure over $408 million for facility improvements, enhancing water systems, power generation, and more.
Tom Stanley of Biloxi, Mississippi, received the NASA Exceptional Achievement Medal for contributions to improve NASA’s technology transfer process. As the NASA Stennis technology transfer officer, he developed a tool to standardize and automate evaluation of software usage agreements, reducing costs by 10 times and evaluation time by 75%. The changes led to record numbers of agreements awarded. Stanley also created a tool for contract closeouts, which has contributed to cost savings for the agency.
Cary Tolman of Fort Walton Beach, Florida, received the NASA Exceptional Achievement Medal for work in the NASA Office of the General Counsel. Beyond her role as procurement attorney, Tolman established a software and management audit review team to provide consistent and timely legal advice on software licenses and terms. Tolman’s work has helped NASA save $85 million and simplified legal support for software issues while reducing cybersecurity and financial risk.
Casey Wheeler of Gulfport, Mississippi, received the NASA Exceptional Achievement Medal for leadership and innovation in replacing the high pressure water industrial water system that supports crucial testing facilities at NASA Stennis. As project manager in the NASA Stennis Center Operations Directorate, Wheeler showcased his planning and coordination skills by completing the complex project without delaying rocket engine testing. His work restored the system to full design pressure in an area that directly supports NASA’s SLS (Space Launch System) rocket through RS-25 engine testing, and other critical projects.
Dale Woolridge of Slidell, Louisiana, received the NASA Exceptional Achievement Medal in absentia for contributions as project manager in the NASA Stennis Center Operations Directorate. Woolridge successfully led multiple construction projects, completing them on time and within budget. One notable project was the refurbishment of the miter gates at NASA Stennis’ navigational lock, which supports NASA’s rocket engine testing operations. The team completed the refurbishment ahead of schedule and within budget, ensuring minimal disruption to NASA operations.
Four NASA Stennis employees received NASA’s Early Career Achievement Medal. The medal is awarded to government employees for unusual and significant performance during the first 10 years of an individual’s career in support of the agency.
Briou Bourgeois of Pass Christian, Mississippi, received the NASA Early Career Achievement for his contributions in the NASA Stennis Engineering and Test Directorate. Bourgeois joined NASA in 2017 and has worked on various projects, including the SLS (Space Launch System) core stage Green Run test series and RS-25 engine testing for Artemis missions. Bourgeois played a key role in modifying the liquid oxygen tanking process during the SLS core stage series. He has since become test director in the NASA Stennis E Test Complex and a leader in commercial test projects at NASA Stennis.
Brandon Ladner of Poplarville, Mississippi, received the NASA Early Career Achievement Medal for contributions to the Exploration Upper Stage Test Project on the Thad Cochran Test Stand at NASA Stennis. As the NASA lead mechanical design engineer for the project, Ladner has significantly contributed to the design and build-up of the B-2 position of the Thad Cochran Test Stand in preparation for Green Run testing of the new SLS (Space Launch System) upper stage. He has led in completion of numerous large design packages and provided valuable engineering oversight to improve construction schedule.
Robert Simmers of Slidell, Louisiana, received the NASA Early Career Achievement for his expertise and versatility since joining NASA in 2015 as a member of the NASA Stennis Safety and Mission Assurance Directorate team. He serves as the safety point of contact for the Thad Cochran Test Stand (B-2). In that role, he supported all operations during Green Run testing of NASA’s SLS (Space Launch System) core stage. Simmers also has supported safety audits at various NASA centers. In 2020, he became the NASA Stennis explosive safety officer responsible for explosive safety and compliance.
Robert Williams of Gulfport, Mississippi, received the NASA Early Career Achievement for his work in the NASA Stennis Engineering and Test Directorate. Williams has worked with NASA for eight years, serving as a lead mechanical design engineer for several commercial test projects. Williams is recognized as a subject matter expert in structural systems and has contributed to various NASA Stennis projects, providing technical and modeling expertise.
Two NASA Stennis employees received NASA’s Silver Achievement Medal. The medal is awarded to any government or non-government employee for a stellar achievement that supports one or more of NASA’s core values, when it is deemed to be extraordinarily important and appropriate to recognize such achievement in a timely and personalized manner.
Brittany Bouche of Slidell, Louisiana, received the NASA Silver Achievement Medal for contributions in the NASA Stennis Center Operations Directorate. Bouche has held multiple key roles in the Facilities Services Division, including acting deputy, maintenance and operations lead, and project manager for several construction projects. She has successfully led various design and construction projects, completing them on time and within budget. These include a $9.1 million sewage system and treatment repair project, successfully completed with minimal service impact.
Andrew Bracey of Picayune, Mississippi, received the NASA Silver Achievement Medal for contributions as a NASA electrical design engineer at NASA Stennis. He has provided critical design support for work related to Green Run testing of the new SLS (Space Launch System) exploration upper stage. Bracey also has been crucial to the NASA Stennis vision of supporting commercial aerospace testing, leading preliminary design reviews for multiple projects onsite.
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Last Updated Aug 14, 2025 EditorNASA Stennis CommunicationsContactC. Lacy Thompsoncalvin.l.thompson@nasa.gov / (228) 688-3333LocationStennis Space Center Related Terms
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By NASA
Explore Hubble Science Hubble Space Telescope NASA’s Hubble Uncovers Rare… 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 AI and Hubble Science Explore the Night Sky Observatory Hubble Observatory Hubble Design Mission Operations Missions to Hubble Hubble vs Webb Team Hubble Team Career Aspirations Hubble Astronauts Multimedia Images Videos Sonifications Podcasts e-Books Online Activities 3D Hubble Models Lithographs Fact Sheets Posters Hubble on the NASA App Glossary News Hubble News Social Media Media Resources More 35th Anniversary Online Activities 5 min read
NASA’s Hubble Uncovers Rare White Dwarf Merger Remnant
This is an illustration of a white dwarf star merging into a red giant star. A bow shock forms as the dwarf plunges through the star’s outer atmosphere. The passage strips down the white dwarf’s outer layers, exposing an interior carbon core. Artwork: NASA, ESA, STScI, Ralf Crawford (STScI) An international team of astronomers has discovered a cosmic rarity: an ultra-massive white dwarf star resulting from a white dwarf merging with another star, rather than through the evolution of a single star. This discovery, made by NASA’s Hubble Space Telescope’s sensitive ultraviolet observations, suggests these rare white dwarfs may be more common than previously suspected.
“It’s a discovery that underlines things may be different from what they appear to us at first glance,” said the principal investigator of the Hubble program, Boris Gaensicke, of the University of Warwick in the United Kingdom. “Until now, this appeared as a normal white dwarf, but Hubble’s ultraviolet vision revealed that it had a very different history from what we would have guessed.”
A white dwarf is a dense object with the same diameter as Earth, and represents the end state for stars that are not massive enough to explode as core-collapse supernovae. Our Sun will become a white dwarf in about 5 billion years.
In theory, a white dwarf can have a mass of up to 1.4 times that of the Sun, but white dwarfs heavier than the Sun are rare. These objects, which astronomers call ultra-massive white dwarfs, can form either through the evolution of a single massive star or through the merger of a white dwarf with another star, such as a binary companion.
This new discovery, published in the journal Nature Astronomy, marks the first time that a white dwarf born from colliding stars has been identified by its ultraviolet spectrum. Prior to this study, six white dwarf merger products were discovered via carbon lines in their visible-light spectra. All seven of these are part of a larger group that were found to be bluer than expected for their masses and ages from a study with ESA’s Gaia mission in 2019, with the evidence of mergers providing new insights into their formation history.
Astronomers used Hubble’s Cosmic Origins Spectrograph to investigate a white dwarf called WD 0525+526. Located 128 light-years away, it is 20% more massive than the Sun. In visible light, the spectrum of WD 0525+526’s atmosphere resembled that of a typical white dwarf. However, Hubble’s ultraviolet spectrum revealed something unusual: evidence of carbon in the white dwarf’s atmosphere.
White dwarfs that form through the evolution of a single star have atmospheres composed of hydrogen and helium. The core of the white dwarf is typically composed mostly of carbon and oxygen or oxygen and neon, but a thick atmosphere usually prevents these elements from appearing in the white dwarf’s spectrum.
When carbon appears in the spectrum of a white dwarf, it can signal a more violent origin than the typical single-star scenario: the collision of two white dwarfs, or of a white dwarf and a subgiant star. Such a collision can burn away the hydrogen and helium atmospheres of the colliding stars, leaving behind a scant layer of hydrogen and helium around the merger remnant that allows carbon from the white dwarf’s core to float upward, where it can be detected.
WD 0525+526 is remarkable even within the small group of white dwarfs known to be the product of merging stars. With a temperature of almost 21,000 kelvins (37,000 degrees Fahrenheit) and a mass of 1.2 solar masses, WD 0525+526 is hotter and more massive than the other white dwarfs in this group.
WD 0525+526’s extreme temperature posed something of a mystery for the team. For cooler white dwarfs, such as the six previously discovered merger products, a process called convection can mix carbon into the thin hydrogen-helium atmosphere. WD 0525+526 is too hot for convection to take place, however. Instead, the team determined a more subtle process called semi-convection brings a small amount of carbon up into WD 0525+526’s atmosphere. WD 0525+526 has the smallest amount of atmospheric carbon of any white dwarf known to result from a merger, about 100,000 times less than other merger remnants.
The high temperature and low carbon abundance mean that identifying this white dwarf as the product of a merger would have been impossible without Hubble’s sensitivity to ultraviolet light. Spectral lines from elements heavier than helium, like carbon, become fainter at visible wavelengths for hotter white dwarfs, but these spectral signals remain bright in the ultraviolet, where Hubble is uniquely positioned to spot them.
“Hubble’s Cosmic Origins Spectrograph is the only instrument that can obtain the superb quality ultraviolet spectroscopy that was required to detect the carbon in the atmosphere of this white dwarf,” said study lead Snehalata Sahu from the University of Warwick.
Because WD 0525+526’s origin was revealed only once astronomers glimpsed its ultraviolet spectrum, it’s likely that other seemingly “normal” white dwarfs are actually the result of cosmic collisions — a possibility the team is excited to explore in the future.
“We would like to extend our research on this topic by exploring how common carbon white dwarfs are among similar white dwarfs, and how many stellar mergers are hiding among the normal white dwarf family,” said study co-leader Antoine Bedrad from the University of Warwick. “That will be an important contribution to our understanding of white dwarf binaries, and the pathways to supernova explosions.”
The Hubble Space Telescope has been operating for more than 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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White Dwarf Merger Illustration
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Last Updated Aug 13, 2025 Editor Andrea Gianopoulos Location NASA Goddard Space Flight Center Contact Media Claire Andreoli
NASA’s Goddard Space Flight Center
Greenbelt, Maryland
claire.andreoli@nasa.gov
Ray Villard
Space Telescope Science Institute
Baltimore, Maryland
Bethany Downer
ESA/Hubble
Garching, Germany
Related Terms
Hubble Space Telescope Astrophysics Astrophysics Division Goddard Space Flight Center Stars The Universe White Dwarfs
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Science Paper: A hot white dwarf merger remnant revealed by an ultraviolet detection of carbon, PDF (23.45 MB)
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