Peekaboo!

Clockwise from left, JAXA (Japan Aerospace Exploration Agency) astronaut Kimiya Yui and NASA astronauts Jonny Kim, Zena Cardman, and Mike Fincke pose for a playful portrait through a circular opening in a hatch thermal cover aboard the International Space Station on Sept. 18, 2025. The cover provides micrometeoroid and orbital debris protection while maintaining cleanliness […]more
https://www.nasa.gov/image-article/peekaboo-2/

Peekaboo!

Clockwise from left, JAXA (Japan Aerospace Exploration Agency) astronaut Kimiya Yui and NASA astronauts Jonny Kim, Zena Cardman, and Mike Fincke pose for a playful portrait through a circular opening in a hatch thermal cover aboard the International Space Station on Sept. 18, 2025.

The cover provides micrometeoroid and orbital debris protection while maintaining cleanliness and pressure integrity in the vestibule between Northrop Grumman’s Cygnus XL cargo spacecraft and the orbital outpost. The opening allows for visual inspection of hatch alignment, access to the hatch handle or pressure equalization valve, and visibility for sensors or cameras during berthing operations.

Kim recently returned to Earth after 245 days in space aboard the orbital laboratory. Yui, Cardman, and Fincke remain aboard the space station, with Fincke as commander.

Image credit: NASA/Jonny Kim

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https://www.nasa.gov/image-article/peekaboo-2/

Toxicology and Environmental Chemistry

Ensuring Astronaut Safety Achieving safe exploration of space in vehicles that rely upon closed environmental systems to recycle air and water to sustain life and are operated in extremely remote locations is a major challenge. The Toxicology and Environmental Chemistry (TEC) group at Johnson Space Center (JSC) is made up of 2 interrelated groups: Toxicology […]more
https://www.nasa.gov/directorates/esdmd/hhp/toxicology-and-environmental-chemistry/

Toxicology and Environmental Chemistry

Ensuring Astronaut Safety

Achieving safe exploration of space in vehicles that rely upon closed environmental systems to recycle air and water to sustain life and are operated in extremely remote locations is a major challenge. The Toxicology and Environmental Chemistry (TEC) group at Johnson Space Center (JSC) is made up of 2 interrelated groups: Toxicology support and the Environmental Chemistry Laboratory. The scientists in both groups play an important role in ensuring that the crew of the ISS are breathing clean air and drinking clean water. Personnel within the TEC establish safe spacecraft environmental limits, monitor the air and water quality aboard current spacecraft (ISS and Commercial Crew and Cargo vehicles), and support technology advancements. The TEC employs in-flight monitoring capabilities as well as postflight sample analysis techniques to monitor the air and water quality from spaceflight.

An Agency Resource

The Toxicology group at JSC serves as the NASA-wide resource for aspects of space toxicology and is responsible for several different duties that are focused on protecting crewmembers and spacecraft systems from toxic exposures in spaceflight. These include assessing chemical hazards for flight, establishing limits for contaminants in spacecraft air and water, assessing and evaluating environmental data from spacecraft in flight, and assessing the potential for off-gas products from new vehicles or modules. These assessments are documented in:

The Environmental Chemistry laboratory at JSC occupies approximately 6,000 sq. ft. of laboratory space in one of the newest buildings on site. This is a fully equipped environmental and analytical laboratory with analysts that have supported multiple human spaceflight programs and provided center support for both gas and liquid analysis. The work in the laboratories operates under an ISO 9001/AS9100-certified quality plan with dedicated and independent quality personnel. 

The Environmental Chemistry Laboratory monitors for contaminants in spacecraft air using both in-flight and post-flight methods. Onboard the International Space Station (ISS), 2 Air Quality Monitors (AQMs) use gas chromatography/differential mobility spectrometry to detect and quantify 23 target volatile organic compounds to provide near real-time insight into the status of the ISS atmosphere. Other real-time monitors supported by the Environmental Chemistry laboratory include the compound-specific analyzer-combustion products (CSA-CP), which use electrochemical sensors to analyze the atmosphere for the presence of compounds produced by fire, and the CO2 monitor, which uses non-dispersive infrared reflectance to monitor for the presence of elevated CO2. For detailed post-flight analysis in the Environmental Chemistry Laboratory, astronauts use grab sample containers to collect in-flight samples, which are then returned to JSC for a detailed environmental analysis. Similarly, formaldehyde monitoring kits contain badges used to collect formaldehyde. These also are returned to the ground for spectroscopic analysis. 

The Environmental Chemistry Laboratory also analyzes archival samples returned from the ISS. The majority of water consumed by crewmembers on the ISS is recycled from a combination of condensed atmospheric humidity and urine. This wastewater is then treated by the U.S. water processor assembly (WPA) to produce potable water, which is analyzed to ensure that the water meets U.S. potability requirements. Samples of the humidity condensate and condensate/urine distillate also are returned for analysis to provide insight into the operation of the WPA and the overall US water recovery system. The TEC relies upon the in-flight analytical capability provided by the ISS total organic carbon analyzer (TOCA) to determine real-time total organic carbon concentrations, which are used to protect ISS crew health as well as manage the U.S. water system consumables. Similarly, the colorimetric water quality monitoring kit (CWQMK) is used to provide insight into the biocide concentration in the U.S. water.

Water samples are also collected in flight and stored for return to Johnson Space Center.  The following ground-based equipment is used to analyze archival samples to ensure suitable air and water quality:

• Liquid Chromatography/Refractive Index Detection (LC/RI)
• Gas Chromatography/Flame Ionization Detector (GC/FID)
• Gas Chromatography/Thermal Conductivity Detector (GC/TCD)
• Trace Gas Analyzer
• Gas Chromatography/Mass Spectrometry (GC/MS)
• Liquid Chromatography/Mass Spectrometry (LC/MS)
• Inductively Coupled Plasma/Mass Spectrometry (ICP/MS)
• Ion Chromatography (IC)
• UV/VIS Spectrophotometry
• Fourier Transform Infrared Reflectance (FTIR)
• Total Organic Carbon Analyzer (TOCA)

In addition to analysis of flight samples and real-time data, the Environmental Chemistry laboratory team plays an important role in the development of new Environmental Control and Life Support Systems hardware by providing analytical support during ground testing. Similarly, the TEC scientists pursue and support technology demonstrations aimed at developing new methods for real-time data collection. Recent examples of this support have included the multi-gas monitor (MGM) and the personal CO₂ monitor. TEC scientists make vital contributions to consolidating environmental monitoring hardware to reduce mass and volume requirements, both of which are important as NASA moves to more long-term missions in smaller vehicles.

Spaceflight Air and Water Quality

Toxicology and Environmental Chemistry (TEC) monitors airborne contaminants in both spacecraft air and water. In-flight monitors are employed to provide real-time insight into the environmental conditions on ISS. Archival samples are collected and returned to Earth for full characterization of ISS air and water.

Points of Contact

Paul Mudgett, PhD
Valerie Ryder, PhD DABT
Spencer Williams, PhD DABT
William T. Wallace, PhD

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https://www.nasa.gov/directorates/esdmd/hhp/toxicology-and-environmental-chemistry/

Statistics and Data Science

Enabling Successful Research A major aim of biomedical research at NASA is to acquire data to evaluate, understand, and assess the biomedical hazards of spaceflight and to develop effective countermeasures. Data Science (S&DS) personnel provide statistical support to groups within the NASA JSC Human Health and Performance Directorate and other NASA communities. They have expertise […]more
https://www.nasa.gov/directorates/esdmd/hhp/biostatistics-and-data-science/

Statistics and Data Science

Enabling Successful Research

A major aim of biomedical research at NASA is to acquire data to evaluate, understand, and assess the biomedical hazards of spaceflight and to develop effective countermeasures. Data Science (S&DS) personnel provide statistical support to groups within the NASA JSC Human Health and Performance Directorate and other NASA communities. They have expertise in the development of complex study designs, the application of modern statistical methods, and the analysis of data collected under NASA operational constraints (small sample sizes, the limited population of astronauts). 

Data Science Support

Beyond statistics, the group aids with data engineering and exploring data. Data engineering includes extracting and transforming data in preparation for analysis and visualization. Data can come in many different formats, the S&DS team helps researchers harmonize (bring data sets together) information across sources. Exploration includes initial analysis and building informative visualizations to deepen the understanding of the evidence. Analyzing and interpreting data to produce insights follow. 

Statistical Consulting Services

The S&DS team provides collaboration and consulting expertise to the Directorate in the application of statistical theory and practice to ongoing biomedical research. Personnel aid in the preparation of sections of research proposals that deal with experiment design, statistical modeling, and subsequent analysis of anticipated research data. Once data are gathered, S&DS statisticians assist with analysis, visualization, and interpretation of results so that investigators can extract the most information while maintaining statistical integrity. A S&DS statistician may be a co-investigator on a project requiring sophisticated statistical modeling and/or analysis techniques. Through collaboration, members of the S&DS team expand their knowledge base in such diverse medical fields as environmental physiology, osteopathy, neurology, pharmacology, microbiology, cardiology, nutrition, and psychology. To meet the unique data collected by NASA, statisticians may develop new techniques to address challenges such as small sample sizes of ISS studies, missing data, operational constraints, and novel measures of outcome. 

Outreach

Collaborators with the S&DS team often reside within the Directorate, but statistics and data science support is extended to other organizations within the Johnson Space Center, including the Engineering Directorate, Human Resources, and the Education Office. The S&DS team also provides a venue wherein high school, undergraduate, and graduate interns can participate in the analysis and interpretation of NASA biomedical data. Students assigned to the S&DS team have a rare opportunity to gain real-world experience with research in a variety of biomedical fields.

Point of Contact

Millennia Young, PhD

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https://www.nasa.gov/directorates/esdmd/hhp/biostatistics-and-data-science/

One of NASA’s Key Cameras Orbiting Mars Takes 100,000th Image

Mesas and dunes stand out in the view snapped by HiRISE, one of the imagers aboard the agency’s Mars Reconnaissance Orbiter. After nearly 20 years at the Red Planet, NASA’s Mars Reconnaissance Orbiter (MRO) has snapped its 100,000th image of the surface with its HiRISE camera. Short for High Resolution Imaging Science Experiment, HiRISE is […]more
https://www.nasa.gov/missions/mars-reconnaissance-orbiter/one-of-nasas-key-cameras-orbiting-mars-takes-100000th-image/

One of NASA’s Key Cameras Orbiting Mars Takes 100,000th Image

Mesas and dunes stand out in the view snapped by HiRISE, one of the imagers aboard the agency’s Mars Reconnaissance Orbiter.

After nearly 20 years at the Red Planet, NASA’s Mars Reconnaissance Orbiter (MRO) has snapped its 100,000th image of the surface with its HiRISE camera. Short for High Resolution Imaging Science Experiment, HiRISE is the instrument the mission relies on for high-resolution images of features ranging from impact craters, sand dunes, and ice deposits to potential landing sites. Those images, in turn, help improve our understanding of Mars and prepare for NASA’s future human missions there. 

Captured Oct. 7, this milestone image from the spacecraft shows mesas and dunes within Syrtis Major, a region about 50 miles (80 kilometers) southeast of Jezero Crater, which NASA’s Perseverance rover is exploring. Scientists are analyzing the image to better understand the source of windblown sand that gets trapped in the region’s landscape, eventually forming dunes. 

“HiRISE hasn’t just discovered how different the Martian surface is from Earth, it’s also shown us how that surface changes over time,” said MRO’s project scientist, Leslie Tamppari of NASA’s Jet Propulsion Laboratory in Southern California. “We’ve seen dune fields marching along with the wind and avalanches careening down steep slopes.” 

The subject of the 100,000th image was recommended by a high school student through the HiWish site, where anyone can suggest parts of the planet to study. Team members at University of Arizona in Tucson, which operates the camera, also make 3D models of HiRISE imagery so that viewers can experience virtual flyover videos. 

“Rapid data releases, as well as imaging targets suggested by the broader science community and public, have been a hallmark of HiRISE,” said the camera’s principal investigator, Shane Byrne of the University of Arizona in Tucson. “One hundred thousand images just like this one have made Mars more familiar and accessible for everyone.” 

More about MRO 

NASA’s Jet Propulsion Laboratory in Southern California manages MRO for NASA’s Science Mission Directorate in Washington as part of NASA’s Mars Exploration Program portfolio. Lockheed Martin Space in Denver built MRO and supports its operations. 

The University of Arizona in Tucson operates HiRISE, which was built by Ball Aerospace & Technologies Corp., in Boulder, Colorado. 

For more information, visit:

https://science.nasa.gov/mission/mars-reconnaissance-orbiter

News Media Contacts

Andrew Good 
Jet Propulsion Laboratory, Pasadena, Calif. 
818-393-2433 
andrew.c.good@jpl.nasa.gov 

Karen Fox / Molly Wasser 
NASA Headquarters, Washington
202-358-1600
karen.c.fox@nasa.gov / molly.l.wasser@nasa.gov

2025-140

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https://www.nasa.gov/missions/mars-reconnaissance-orbiter/one-of-nasas-key-cameras-orbiting-mars-takes-100000th-image/

Maintaining the Gold Standard: The Future of Landsat Calibration and Validation

The NASA CalVal team spent 2025 improving their calibration techniques, strengthening collaboration, and sharing their work with the remote sensing community. Looking ahead, they’re applying lessons learned to prepare for future Landsat missions.more
https://science.nasa.gov/missions/landsat/maintaining-the-gold-standard-the-future-of-landsat-calibration-and-validation/

Maintaining the Gold Standard: The Future of Landsat Calibration and Validation

By Amit Angal, Senior Engineer at Goddard Space Flight Center

The Landsat Calibration and Validation (Cal/Val) group helps uphold Landsat’s reputation as the gold standard of satellite imagery. They ensure that the Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS) aboard Landsats 8 and 9 provide high-quality scientific measurements to users around the world. In 2025, the Cal/Val group contributed over 60 pages to the second edition of “Comprehensive Remote Sensing” (Kaita et. al, 2026), organizing content from NASA, USGS, academia, and industry scientists. Cal/Val support staff authored multiple sections, including a summary of results from Landsat 9 and of the evolution of spectral, spatial, and radiometric characteristics throughout the Landsat missions.

The Cal/Val team at NASA Goddard Space Flight Center works closely with the Landsat Flight Operations Team to plan weekly calibration activities to maintain the radiometric accuracy of Landsat products. In October 2025, a Landsat 9 anomaly occurred related to its solar array drive assembly (SADA) potentiometer. The spacecraft and instruments were placed in a safehold, pausing data collections. The Cal/Val team assessed the instruments after they recovered from this anomaly, including monitoring the instrument telemetry, detector gains, and noise performance. The team identified a mis-loaded detector map and updated the calibration of both the reflective and thermal emissive bands to ensure consistent, accurate data. After six days in the safehold, the instrument resumed normal operations. 

The NASA Cal/Val team supports their USGS counterparts with quarterly updates to the Calibration Parameter File (CPF) by providing inputs for relative and absolute gains as needed. This work involves collaborating with USGS scientists to ensure the consistency of the Combined Radiometric Model (CRaM). The CRaM approach integrates radiometric responses from on-board calibrators to enhance long-term calibration stability throughout mission lifetimes. The CRaM algorithm also provides an extensible framework for future satellite missions. A peer-reviewed publication detailing the CRaM’s approach and future applications was submitted to Science of Remote Sensing.

On January 14-16, 2025, the Landsat Cal/Val team organized and hosted the first semiannual Technical Information Meeting (TIM) at NASA Goddard Space Flight Center. NASA and USGS scientists welcomed collaborating scientists from South Dakota State University (SDSU), the University of Arizona Tucson, and Rochester Institute of Technology for presentations and discussions on Landsat imaging performance, algorithms, and instrument health. On May 28-29, 2025, the Cal/Val team attended the second semiannual TIM at SDSU.

The Landsat Cal/Val Team is validating the accuracy of the Harmonized Landsat and Sentinel-2 (HLS) v2.0 product, which combines data from multiple satellites to create a continuous record of Earth’s surface reflectance measurements since 2013. The team is testing the dataset using RadCalNet, a global network of automated ground stations that provide precise, standardized measurements. The team compared measurements from four RadCalNet sites, including the well-established Railroad Valley Playa site in Nevada, against near-simultaneous HLS data. Their analysis shows the satellite and ground measurements agree within expected uncertainty ranges—a strong validation of the HLS product’s accuracy.

The team presented these findings at the CEOS IVOS calibration meeting in Tucson, Arizona (September 1-5, 2025) and is currently preparing a peer-reviewed article to share the complete results.

Path Forward

The Cal/Val team applies lessons learned from Landsat missions to better plan calibration efforts for the next generation of instruments. Using instrument performance checklists from Landsat 8/9, the team is building a framework of in-house geometric and radiometric testing and extending algorithms for future Landsat instruments.

The Landsat Cal/Val Team is actively tackling a critical challenge in solar irradiance modeling. While new hyperspectral sensor technologies have made it possible to create highly accurate solar models with much lower uncertainty, the remote sensing community still lacks agreed-upon methods for applying these advanced models. A dedicated subgroup within the Landsat Cal/Val Team is now developing and testing standardized approaches to bridge this gap. Their goal is to create clear recommendations and best practices that the scientific community can refine together and implement consistently.

This work addresses a fundamental need—transforming promising hyperspectral solar modeling capabilities into practical, standardized tools that researchers can confidently use across different projects and applications.

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https://science.nasa.gov/missions/landsat/maintaining-the-gold-standard-the-future-of-landsat-calibration-and-validation/

Microbiology

Microorganisms and Spaceflight Spaceflight poses a risk of adverse health effects due to the interactions between microorganisms, their hosts, and their environment. The JSC Microbiology team addresses the benefits and risks related to microorganisms, including infectious disease, allergens, environmental and food contamination, and the impacts of changes in environmental and human microbial ecology aboard spacecraft. […]more
https://www.nasa.gov/directorates/esdmd/hhp/microbiology/

Microbiology

Microorganisms and Spaceflight

Spaceflight poses a risk of adverse health effects due to the interactions between microorganisms, their hosts, and their environment. The JSC Microbiology team addresses the benefits and risks related to microorganisms, including infectious disease, allergens, environmental and food contamination, and the impacts of changes in environmental and human microbial ecology aboard spacecraft. The team includes certified medical technologists, environmental microbiologists, mycologists, and biosafety professionals.

The JSC Microbiology laboratory is a critical component of the Human Health and Performance Directorate and is responsible for addressing crew health and environmental issues related to microbial infection, allergens, and contamination. This responsibility is achieved by operational monitoring and investigative research using classical microbiological, advanced molecular, and immunohistochemical techniques. This research has resulted in a significant number of presentations and peer-reviewed publications contributing to the field of Microbiology with articles in journals such as Infection and Immunity, Journal of Infectious Disease and Applied and Environmental Microbiology, Nature Reviews Microbiology, and Proceedings of the National Academies of Science.

Keeping Crew-members Safe

As a functional part of the Crew Health Care System and in support of Environmental Control and Life Support Systems engineers, the Microbiology Laboratory team defines requirements, coordinates and analyzes microbial sampling, and analysis of air, surface, and water samples. These environmental samples, including preflight and in-flight samples, re-analyzed to ensure that microorganisms do not adversely affect crew health or system performance.

Microbiologists also serve as team members when anomalous events occur that might affect crew health or life support systems operations. Spaceflight food samples also are evaluated preflight to decrease the risk of infectious disease to the crew.

Technology and Hardware

• ABI DNA sequencer
• Illumina MiSeq desktop sequencer
• Oxford Nanopore Technologies MinION DNA / RNA sequencers
• Agilent Bioanalyzer
• VITEK 2 Microbial Identification
• ​Space analogue bioreactors

Points of Contact

Mark Ott, PhD
Sarah Wallace, PhD
Hang Nguyen, PhD

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https://www.nasa.gov/directorates/esdmd/hhp/microbiology/

Immunology and Virology

Does Spaceflight Alter the Human Immune System? Getting sick on Earth is nothing to sneeze at, but for astronauts on deep space exploration missions, the risk for contracting diseases may be elevated due to altered immunity. The Human Health and Performance Directorate’s Immunology/Virology Laboratory is ideally suited to study the effects of spaceflight on the […]more
https://www.nasa.gov/directorates/esdmd/hhp/immunology-and-virology/

Immunology and Virology

Does Spaceflight Alter the Human Immune System?

Getting sick on Earth is nothing to sneeze at, but for astronauts on deep space exploration missions, the risk for contracting diseases may be elevated due to altered immunity. The Human Health and Performance Directorate’s Immunology/Virology Laboratory is ideally suited to study the effects of spaceflight on the immune system. When immune cells do not function properly, the immune system cannot respond properly to threats. This may increase susceptibility to infectious disease. Altered immunity can also lead to latent virus shedding, which is the “reawakening” of certain viruses we contract in our youth by which stay with us through adulthood. Reactivation of these viruses has been observed in some crewmembers. Conversely, when immune activity heightens, the immune system reacts excessively, resulting in things like allergy or persistent rashes, which also have been reported by some crewmembers during flight. Working in collaboration with the Human Research Program, the Immunology/Virology Laboratory is actively working to characterize the changes in astronauts’ immune system during spaceflight as well as developing countermeasures to help mitigate the clinical risks for astronauts during these missions to other planets, moons, or asteroids.

Understanding the Impact of Spaceflight on Human Immune Systems

Immunology/Virology Laboratory team supported studies conducted aboard the Space Shuttle and supports investigations currently performed aboard the ISS. For studies of astronauts, the laboratory validated a novel sampling strategy to return ambient live astronaut blood samples to Earth for comprehensive immunological testing and has developed several novel biomedical assays to evaluate immunity in humans. Results from a recent immunology investigation aboard the ISS called “Validation of Procedures for Monitoring Crewmember Immune Function” or “Integrated Immune”’ were published in the journal Nature Microgravity. The data confirms that ISS crews have alterations in both the number and function of certain types of immune cells and that these alterations persist for the duration of a 6-month spaceflight. Other data from the study published in the Journal of Interferon & Cytokine Research indicates that ISS crews have changes in their blood levels of specific immune proteins called ”cytokines” during flight which persist for the duration of a 6-month mission. The laboratory is currently preparing to support physiological monitoring of Artemis deep space astronauts via novel technology developed in-house. 

Learning About Spaceflight While on Earth  

The Immunology/Virology Laboratory also supports human investigations performed in Earth-based “space analog” situations. Such analogs are places where some specific conditions of spaceflight are replicated. Examples include undersea deployment, closed chamber isolation, or Antarctica winter over. Analog work may shed mechanistic light on the causes of alterations observed during flight or provide locations useful for the testing of countermeasures. The Immunology Laboratory recently supported a European Space Agency 2-year study performed at Concordia Station, Dome C, and Antarctica. Biomedical samples were collected, processed, and stabilized over the Antarctica winter by Concordia crewmembers, and preserved for shipment to NASA. The data revealed that Concordia crewmembers also experience unique patterns of immune dysregulation, some of which are like astronauts’ patterns. The laboratory also has supported recent studies in Antarctica at McMurdo Station, Neumayer III Station, and Palmer Station.

The Immunology/Virology Laboratory team also participates in ground-based investigations to determine the mechanistic reasons why certain types of immune cells do not function well during microgravity conditions. For these studies, a terrestrial “model” of microgravity cell culture is employed, referred to as “clinorotation.” Essentially, cell cultures are slowly rotated around a horizontal axis. During clinorotation, immune cells generally respond as they would during spaceflight.

Improving Life in Space and on Earth

To “connect the dots” between observed immune changes in astronauts and potential adverse clinical consequences, the Immunology/Virology Laboratory team may support Earth-based clinical investigations. These investigations consist of studies, conducted in collaboration with physicians, of defined patent populations. The same assays, which define immune changes in astronauts, may be applied to clinical patients and the data will help NASA scientists and flight surgeons interpret the flight information, in the context of clinical risk to astronauts. To date, the Immunology/Virology Laboratory team has supported a European clinical investigation of emergency room patients, and a Houston-based investigation of shingles patients.

The Immunology/Virology Laboratory team has developed, working with translational scientists all over the world, a potential countermeasure to improve immunity in deep-space astronauts. The protocol published in the Frontiers in Immunology consists of stress-relieving techniques, certain nutritional supplements, a prescription of aerobic and resistive exercise, certain medications, and monitoring. This protocol soon will be tested at Palmer Station, Antarctica, to be followed by a flight validation aboard ISS. 

Our Facility, Technology, and Hardware

Immunologists and virologists comprise the core research staff of the laboratory and postdoctoral associates, visiting scientists, and graduate students routinely perform rotations of varying lengths in the laboratory. The laboratory currently possesses an array of sophisticated research equipment, including:

• Ten-, and Four-color Flow Cytometers
• 41-analyte capable Multiplex Analyzer
• Real-time Polymerase Chain Reaction System
• Fluorescent Microscopes
• Confocal Microscope
• Cell culture, including modeled-microgravity, facilities

In addition, we partner with the Bioanalytical Core Laboratory (BCL) to leverage equipment such as the environmental scanning electron microscope.

Points of Contact

Brian Crucian, PhD
Mayra Nelman-Gonzalez
Satish Mehta, PhD

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https://www.nasa.gov/directorates/esdmd/hhp/immunology-and-virology/

Exposure Guidelines (SMACs and SWEGs)

The JSC toxicologists establish guidelines for safe and acceptable levels of individual chemical contaminants in spacecraft air (SMACs) and drinking water (SWEGs) in collaboration with the National Research Council’s Committee on Toxicology (NRC COT) and through peer-reviewed publication.  The framework for establishing these levels is documented for SMACs and SWEGs, and recent refinements to the Methods reflect current risk assessment […]more
https://www.nasa.gov/directorates/esdmd/hhp/exposure-guidelines-smacs-and-swegs/

Exposure Guidelines (SMACs and SWEGs)

The JSC toxicologists establish guidelines for safe and acceptable levels of individual chemical contaminants in spacecraft air (SMACs) and drinking water (SWEGs) in collaboration with the National Research Council’s Committee on Toxicology (NRC COT) and through peer-reviewed publication.  The framework for establishing these levels is documented for SMACs and SWEGs, and recent refinements to the Methods reflect current risk assessment practices.

In addition to official SMACs used for the evaluation of spacecraft air, JSC toxicologists set interim 7-day SMAC values that are listed in NASA Marshall Space Flight Center’s Materials and Processes Technical Information System (“MAPTIS”), which is used to evaluate materials and hardware off-gassing data.  

Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants

A table listing the official NASA SMAC values is published in JSC 20584 (PDF, 1MB) (Last revised – June 2024). References for the published values are provided below:

• NRC (1994) Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants, Volume 1, National Academy Press, Washington, D.C.
• NRC (1996) Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants, Volume 2, National Academy Press, Washington, D.C.
• NRC (1996) Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants, Volume 3, National Academy Press, Washington, D.C.
• NRC (2000) Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants, Volume 4, National Academy Press, Washington, D.C.
• NRC (2008) Spacecraft Maximum Allowable Concentrations for Selected Airborne Contaminants, Volume 5, National Academy Press, Washington, D.C.
• Meyers VE, Garcia HD, James JT. Safe Human Exposure Limits for Airborne Linear Siloxanes during Spaceflight. Inhalation Toxicology 2013; 25(13):735-46.
• Romoser AA, Ryder VE, McCoy JT. Spacecraft Maximum Allowable Concentrations for Manganese Compounds in Mars Dust. Aerosp Med Hum Perform. 2019; 90(8):709-719.
• Scully RR, Garcia H, McCoy JT, Ryder VE. Revisions to Limits for Methanol in the Air of Spacecraft. Aerosp Med Hum Perform. 2019; 90(9):807-812.
• Garcia, H.D, Acceptable Limits for n-Hexane in Spacecraft Atmospheres. Aerospace Medicine and Human Performance. 2021;92(12);956-961. 
• Ryder, V.E. and Williams, E.S. Revisions to Limits for Propylene Glycol in Spacecraft Air. Aerospace Medicine and Human Performance. 2022; 93(5);467-469. 
• Lam CW, Ryder VE. Spacecraft Maximum Allowable Concentrations for Hydrogen Fluoride. Aerospace Medicine and Human Performance. 2022; 93(10)746-748.
• Williams ES, Ryder VE. Spaceflight Maximum Allowable Concentrations for Ethyl Acetate. Aerospace Medicine and Human Performance. 2023; 94(1):25–33.
• Ryder VE and Williams ES. Revisions to Acute/Off-Nominal Limits for Benzene in Spacecraft Air. Aerospace Medicine and Human Performance. 2023; 94(7):544–545.
• Wimberly, AA and Ryder VE. Exposure Limits for Hydrogen Sulfide in Spaceflight. NASA/TM-20240000101, NASA Johnson Space Center, 2024.
• Tapia CM, Langford SD, Ryder VE. Revisions to Limits for Toluene in Spacecraft Air. Aerosp Med Hum Perform. 2024; 95(7):399-402.
• Ryder VE. Revisions to limits for 2-propanol in spacecraft air. Aerosp Med Hum Perform. 2025; 96(4):360–362.
• Williams ES, Tapia CM, Ryder V. Revisions to spacecraft maximum allowable concentrations for acetaldehyde. Aerosp Med Hum Perform. 2025; 96(11):1019–1023.
• Ryder VE. Revisions to Spacecraft Maximum Allowable Concentrations for 2-Butanone. Aerosp Med Hum Perform. 2025 Dec;96(12):1094-1097.

Spacecraft Water Exposure Guidelines for Selected Waterborne Contaminants

A table listing the official NASA SWEG values is published in JSC 63414 Rev A (PDF, 426KB) (Last revised – November 2023). References for the published values are provided below:

• NRC (2004) Spacecraft Water Exposure Guidelines for Selected Contaminants, Volume 1, National Academy Press, Washington, D.C.
• NRC (2006) Spacecraft Water Exposure Guidelines for Selected Contaminants, Volume 2, National Academy Press, Washington, D.C.
• NRC (2008) Spacecraft Water Exposure Guidelines for Selected Contaminants, Volume 3, National Academy Press, Washington, D.C.
• Ramanathan R, James JT, McCoy T. (2012) Acceptable levels for ingestion of dimethylsilanediol in water on the International Space Station. Aviat Space Environ Med. 83(6):598-603.
• Garcia, HD, Tsuji, JS, James, JT. (2014) Establishment of exposure guidelines for lead in spacecraft drinking water. Aviat Space Environ Med. 85:715-20.

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https://www.nasa.gov/directorates/esdmd/hhp/exposure-guidelines-smacs-and-swegs/

What’s Next for HLS

In 2025, the Harmonized Landsat and Sentinel-2 (HLS) program established itself as a cornerstone for global medium-resolution optical Earth observation and became one of NASA’s most downloaded products.more
https://science.nasa.gov/missions/landsat/whats-next-for-hls/

What’s Next for HLS

Harmonized Landsat and Sentinel-2 PI Christopher Neigh shares milestones and a vision for the future

In 2025, the Harmonized Landsat and Sentinel-2 (HLS) program established itself as a cornerstone for global medium-resolution optical Earth observation and became one of NASA’s most downloaded products. The seamless, analysis-ready dataset is free for anyone to use and download on NASA Earthdata: HLSL30v2.0 and HLSS30v2.0. HLS version 2.0 (Ju et al., 2025), released in July, represents a major advancement in algorithm sophistication and dataset completeness. The improved surface reflectance dataset now extends globally back to 2013 (excluding Antarctica) and integrates observations from Landsat 8/9 and Sentinel-2A/B/C satellites, achieving an unprecedented median revisit interval of less than 1.6 days. This high frequency of observations transforms our ability to monitor Earth’s changing surface.

June saw the first in-person HLS meeting between NASA headquarters, the Satellite Needs Working Group (SNWG), and representatives from NASA’s Goddard Space Flight Center and Marshall Space Flight Center, representing enhanced coordination and strategic alignment. The HLS project also serves as a critical steppingstone for advancing collaboration between NASA and the European Space Agency (ESA).

HLS’s frequent revisit is one of its key values to data users. Zhou et al. (2025) evaluated the cloud-free coverage of HLS V2.0 in 2022 and found that HLS data provided observations every 1.6 days at the global scale and 2.2 days in data-scarce tropical regions. This temporal resolution addresses one of the most persistent challenges in optical remote sensing: obtaining cloud-free observations for time-sensitive applications.

HLS Impacts

Already, scientists are putting HLS to use for practical and scientific applications. Zhou et al. (2025) evaluated the global consistency, reliability, and uncertainty of the newly-released suite of nine HLS vegetation indices. This assessment provides the scientific community with confidence in using HLS-derived vegetation indices for agriculture, forestry, ecosystem monitoring, and more.

Pickens et al. (2025) unveiled a global land change monitoring system, DIST-ALERT, based on HLS data. DIST-ALERT highlights HLS’s transformative impact on environmental monitoring, identifying new land change dynamics that are impossible to track with Landsat or Sentinel observations alone.

Vision for the Future

The HLS program continues to evolve to deliver high-quality, reliable data to its expanding user base. Shi et al. (2026, under review in Remote Sensing of Environment) developed Fmask version 5.0, employing a hybrid approach combining physical rules, machine learning, and deep learning for cloud masking. When released, this next-generation cloud detection algorithm will improve the accuracy and consistency of cloud/cloud-shadow screening—a critical component for maximizing usable observations in the HLS time series.

Looking forward, the HLS vision encompasses:

• Enhanced Algorithms: Integrating Fmask v5.0 and refining harmonization algorithms to further reduce inter-sensor differences and improve accuracy across diverse conditions.
• Expanded Product Suite: Developing products that leverage HLS’s unique temporal resolution.
• Meeting User Needs: Strengthening partnerships with operational agencies and downstream users to ensure HLS products effectively support applications including agriculture, water resources, disaster response, and climate adaptation.
• Continuity and Sustainability: Planning for long-term data continuity as Landsat Next and future Sentinel missions come online, ensuring seamless transition and multi-decadal consistency.
• Community Engagement: Expanding training, documentation, and outreach to maximize HLS adoption across the global user community, particularly in regions where frequent, free, analysis-ready data can transform environmental monitoring capabilities.

The HLS program exemplifies successful international collaboration in Earth observation, delivering on the promise of harmonized, frequent, global-scale monitoring. As we build on the foundation of HLS v2.0, the program is positioned to enable breakthrough science and operational applications that were previously impossible with individual satellite missions alone.

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https://science.nasa.gov/missions/landsat/whats-next-for-hls/

NASA’s Webb Observes Exoplanet Whose Composition Defies Explanation

Scientists using NASA’s James Webb Space Telescope have observed a rare type of exoplanet, or planet outside our solar system, whose atmospheric composition challenges our understanding of how it formed.  Officially named PSR J2322-2650b, this Jupiter-mass object appears to have an exotic helium-and-carbon-dominated atmosphere unlike any ever seen before. Soot clouds likely float through the […]more
https://science.nasa.gov/missions/webb/nasas-webb-observes-exoplanet-whose-composition-defies-explanation/

NASA’s Webb Observes Exoplanet Whose Composition Defies Explanation

Scientists using NASA’s James Webb Space Telescope have observed a rare type of exoplanet, or planet outside our solar system, whose atmospheric composition challenges our understanding of how it formed. 

Officially named PSR J2322-2650b, this Jupiter-mass object appears to have an exotic helium-and-carbon-dominated atmosphere unlike any ever seen before. Soot clouds likely float through the air, and deep within the planet, these carbon clouds can condense and form diamonds. How the planet came to be is a mystery. The paper appears Tuesday in The Astrophysical Journal Letters. 

“This was an absolute surprise,” said study co-author Peter Gao of the Carnegie Earth and Planets Laboratory in Washington. “I remember after we got the data down, our collective reaction was ‘What the heck is this?’ It’s extremely different from what we expected.”

Image A: Exoplanet PSR J2322-2650b and Pulsar (Artist’s Concept)

This planet-mass object was known to orbit a pulsar, a rapidly spinning neutron star. A pulsar emits beams of electromagnetic radiation at regular intervals typically ranging from milliseconds to seconds. These pulsing beams can only be seen when they are pointing directly toward Earth, much like beams from a lighthouse.  

This millisecond pulsar is expected to be emitting mostly gamma rays and other high energy particles, which are invisible to Webb’s infrared vision. Without a bright star in the way, scientists can study the planet in intricate detail across its whole orbit. 

“This system is unique because we are able to view the planet illuminated by its host star, but not see the host star at all,” said Maya Beleznay, a third-year PhD candidate at Stanford University in California who worked on modeling the shape of the planet and the geometry of its orbit. “So we get a really pristine spectrum. And we can study this system in more detail than normal exoplanets.” 

“The planet orbits a star that’s completely bizarre — the mass of the Sun, but the size of a city,” said the University of Chicago’s Michael Zhang, the principal investigator on this study. “This is a new type of planet atmosphere that nobody has ever seen before. Instead of finding the normal molecules we expect to see on an exoplanet — like water, methane, and carbon dioxide — we saw molecular carbon, specifically C₃ and C_2.”

Molecular carbon is very unusual because at these temperatures, if there are any other types of atoms in the atmosphere, carbon will bind to them. (Temperatures on the planet range from 1,200 degrees Fahrenheit at the coldest points of the night side to 3,700 degrees Fahrenheit at the hottest points of the day side.) Molecular carbon is only dominant if there’s almost no oxygen or nitrogen. Out of the approximately 150 planets that astronomers have studied inside and outside the solar system, no others have any detectable molecular carbon.

PSR J2322-2650b is extraordinarily close to its star, just 1 million miles away. In contrast, Earth’s distance from the Sun is about 100 million miles. Because of its extremely tight orbit, the exoplanet’s entire year — the time it takes to go around its star — is just 7.8 hours. Gravitational forces from the much heavier pulsar are pulling the Jupiter-mass planet into a bizarre lemon shape.

Image B: Exoplanet PSR J2322-2650b (Artist’s Concept)

Together, the star and exoplanet may be considered a “black widow” system, though not a typical example. Black widow systems are a rare type of double system where a rapidly spinning pulsar is paired with a small, low-mass stellar companion. In the past, material from the companion streamed onto the pulsar, causing the pulsar to spin faster over time, which powers a strong wind. That wind and radiation then bombard and evaporate the smaller and less massive companion. Like the spider for which it is named, the pulsar slowly consumes its unfortunate partner.

But in this case, the companion is officially considered an exoplanet, not a star. The International Astronomical Union defines an exoplanet as a celestial body below 13 Jupiter masses that orbits a star, brown dwarf, or stellar remnant, such as a pulsar.

Of the 6,000 known exoplanets, this is the only one reminiscent of a gas giant (with mass, radius, and temperature similar to a hot Jupiter) orbiting a pulsar. Only a handful of pulsars are known to have planets.

“Did this thing form like a normal planet? No, because the composition is entirely different,” said Zhang. “Did it form by stripping the outside of a star, like ‘normal’ black widow systems are formed? Probably not, because nuclear physics does not make pure carbon. It’s very hard to imagine how you get this extremely carbon-enriched composition. It seems to rule out every known formation mechanism.”

Study co-author Roger Romani, of Stanford University and the Kavli Institute for Particle Astrophysics and Cosmology Institute, proposes one evocative phenomenon that could occur in the unique atmosphere. “As the companion cools down, the mixture of carbon and oxygen in the interior starts to crystallize,” said Romani. “Pure carbon crystals float to the top and get mixed into the helium, and that’s what we see. But then something has to happen to keep the oxygen and nitrogen away. And that’s where the mystery come in.

“But it’s nice to not know everything,” said Romani. “I’m looking forward to learning more about the weirdness of this atmosphere. It’s great to have a puzzle to go after.”

Video A: Exoplanet PSR J2322-2650b and Pulsar (Artist’s Concept)

This animation shows an exotic exoplanet orbiting a distant pulsar, or rapidly rotating neutron star with radio pulses. The planet, which orbits about 1 million miles away from the pulsar, is stretched into a lemon shape by the pulsar’s strong gravitational tides.

Animation: NASA, ESA, CSA, Ralf Crawford (STScI)

With its infrared vision and exquisite sensitivity, this is a discovery only the Webb telescope could make. Its perch a million miles from Earth and its huge sunshield keep the instruments very cold, which is necessary for these observations. It is not possible to conduct this study from the ground.

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).

To learn more about Webb, visit: https://science.nasa.gov/webb

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