Johnson Space Center

Space traffic is increasing rapidly, with a threefold increase in launches and a thirtyfold increase in satellites launched between 2000 and 2024 (Taupin et al., 2025). In 2024, we estimate that the ratio between the re-entered dry-mass from anthropogenic space activities (DISCOSWeb, J.McDowell RCAT) and natural input from Earth’s cosmic natural input (Carrillo-Sánchez et al., 2020) is between 20-40%. For aluminum in particular, this ratio was estimated to exceed 100% in 2024 (Ferreira et al., 2025). In addition, the space traffic increase is mainly occurring below 600 km altitude, where satellites naturally decay in less than ~10 years. This mass is ablated in the form of atoms and solid aerosols that accumulate in the stratosphere. They may impact radiative forcing and ozone depletion, and have other unknown effects at local, regional and global scales (Ferreira et al., 2024, Ross et al., 2014). It is therefore important to accurately quantify the past and present levels of these injections in order to model their atmospheric effects.First, we present a finely tuned classification that helps to assess the potential origin of solid stratospheric aerosols (~1-100 microns diameter) collected in-situ by aircrafts mostly over the United States by NASA's Cosmic Dust program between 1981 and 2020. Here we study the 1981-2010 period comprising more than 4 400 particles. Based on the Energy Dispersive X-ray spectra of these particles and previous work (Lasue et al., 2010), we have developed a semi-automated method that classifies them into compositional clusters. For example, we identified potential artificial contaminants rich in Al, Cd, Cu and Ti that stand out from other clusters. For clarity, the particle compositions are compared to known minerals and pure elements. A visualization of the classification will be presented for each year in which particles were sampled, showing the evolution of the aerosol population composition.Soon, this work will be supplemented by a new spectral analysis of 46 particles that will serve as a calibration to improve the quantification of the chemical composition of all particles in the catalogues.Secondly, we will introduce a new method for estimating the re-entered ablated mass from space waste. Existing methods rely on average ablation coefficients (Schulz et al., 2021) or focus on specific chemical species (Ferreira et al., 2025). We use the DEBRISK software (from CNES) to estimate several average ablation profiles for a few simplified models of satellites and rocket upper stages based on their different average cross-sections, masses, and orbital parameters. Then, we use these parameters available in DISCOSweb to derive the total ablated mass of satellites and rocket upper stages in the stratosphere from 1981 to 2010. Finally, we estimate the total mass of black-carbon and alumina injected in the stratosphere during all orbital launch on the same period, using a newly created database on propellant masses cross-referencing information from different sources (DISCOSweb, J.McDowell GCAT, user manuals). These numbers will then be compared to the evolution of the solid aerosol population presented in the first part.

Multiple orbital studies have highlighted the importance of Fe/Mg phyllosilicate minerals on Mars, especially in Noachian terrains (e.g. Poulet et al., 2006; Mangold et al., 2007;), even showing that they are the dominant hydrous mineral family on Mars (Carter et al., 2013). Although widespread in exposures of the oldest terrains on Mars, it is hard to constrain either their composition or formation process based on orbital data only (Ehlmann et al., 2011; Carter et al., 2015). The best matches for the orbital spectra were proposed to be smectite (nontronite, saponite) and/or vermiculite (Carter et al., 2013). In the Nili Fossae region specifically, the Noachian basement was shown to be bear widespread signatures of Fe/Mg smectites (Goudge et al., 2015).After exploring diverse geological units inside Jezero Crater (Nili Fossae, Mars), and going over the rim of the crater, the Perseverance rover has reached a unit informally called Krokodillen, at the base of the outer part of the rim. It is thought to be part of the Noachian crust that was locally uplifted by the emplacement of Jezero Crater (Sun & Stack et al., 2020). Dark looking from orbit, it is surrounded on the North, West and South by ridges and an exposure of the regional olivine-rich unit, understood to be younger.We will present the data acquired on rocks of the Krokodillen area with the SuperCam instrument (ref Maurice et al., SSR 2021; Wiens et al., SSR 2021). Overall structureless, the rocks of Krokodillen are generally fine grained, with locally some millimetric granules. The chemical composition characterized with LIBS shows a relatively homogeneous composition intermediate between the average basaltic crust of Mars and orthopyroxene. This is likely an average, close to the bulk composition, due to the mixing of multiple fine-grain mineral phases within the footprint of the LIBS analysis. Visible and near infrared (VISIR) reflectance spectroscopy data show strong and ubiquitous signatures of Fe-Mg phyllosilicates, closely matching those observed from orbit in the broader Nili Fossae region.We propose that the rocks of Krokodillen are representative of the Noachian clay-bearing rocks characterized from orbit, specifically the (ridged) Altered Basement mapped by Goudge et al., (2015) in the Jezero watershed. In that case, the in situ measurements from the Mars 2020 mission provide the first in situ constraints on the composition, aqueous alteration and emplacement mechanism of these rocks.

Abstract Doublet fluorescence at 304 and 325‐nm under deep ultraviolet (DUV) excitation was detected on Mars at Jezero crater by the Scanning Habitable Environments with Raman and Luminescence for Organics and Chemicals (SHERLOC) instrument onboard the Mars 2020 rover Perseverance . The doublet was associated with CaSO 4 phases and sourced to organic molecules as the preferred interpretation (Sharma et al., 2023, https://doi.org/10.1038/s41586‐023‐06143‐z ). Reported here are coordinated analyses of terrestrial volcanogenic samples that have, under DUV excitation, intrinsic 304 and 325‐nm fluorescence whose origin is tightly sourced to anhydrite:Ce 3+ (trace‐Ce 3+ for Ca 2+ substitution in natural anhydrous CaSO 4 ). Thermal decomposition products of natural volcanogenic gypsum (CaSO 4 ·2H 2 O) and sedimentary glauberite (Na 2 Ca(SO 4 ) 2 ) by aerial heating at more than 450°C and more than 600°C, respectively, are also characterized by 304 and 325‐nm fluorescence doublets that are sourced from anhydrite:Ce 3+ thermal decomposition products. The 304 and 325‐nm doublet fluorescence detected by SHERLOC is fully explainable by inorganic anhydrite:Ce 3+ resulting from geogenic processes. The volcanogenic samples are products of leaching and precipitation in hydrothermal environments. Leachates can precipitate in many ways, including intimate or proximal contact with residues and, after aqueous transport, as vein precipitate, fracture fill, and evaporite deposits. Equivalent considerations extend to hydrothermalism driven by impact melts and other thermal sources. Laboratory thermal decomposition of progenitor phases to anhydrite:Ce 3+ is an analogous process for contact and burial metamorphism. The coordinated analysis approach additionally includes major element and REE abundances (X‐ray fluorescence and inductive coupled plasma—mass spectrometry), X‐ray diffraction, DUV Raman spectroscopy, and thermal analysis (thermal gravimetry, differential scanning calorimetry, and evolved gas analysis).

Spaceflight stressors such as microgravity and radiation disrupt mitochondria in ocular tissues, leading to impaired energy production, oxidative stress, and reduced repair capacity. The anatomical distribution of mitochondria and disease localization presents an interesting relationship: cortical lens mitochondria align with the type of cataracts seen in spaceflight, while retinal mitochondria correspond to the pathology of SANS. These observations suggest mitochondrial damage may be more central to spaceflight-associated pathologies than previously recognized.

Nominally anhydrous minerals (NAMS), such as plagioclase, may represent a significant volatile reservoir as their low intrinsic volatile content is multiplied many times by their large volumetric abundance. This study reports the volatile concentration of CO 2 , H 2 O, F, P 2 O 5 , S, and Cl in shocked plagioclase from three paired lunar troctolites, Northwest Africa (NWA) 5744, NWA 8676, and NWA 10140, to assess the volatile inventory of the early lunar crust. Measured volatile abundances are typically < 5 ppm, except for P 2 O 5 , which is as high as ∼ 300 ppm. Calculated parental melt estimates range from ∼ 3.2 to 238 ppm H 2 O, 2.3 to 213 ppm F, and 0.13 to 1971 ppm Cl. Whilst the lower ends of these ranges are in keeping with literature values, the higher ends of these ranges may indicate heterogeneity in the early Moon's volatile distribution. The cause or causes of any heterogeneity will remain poorly defined until complementary isotopic data (e.g., H, Cl) and distribution coefficients are known for lunar conditions.

<h2>Summary</h2> Thermal runaway (TR), characterized by rapid exothermic reactions, presents a serious safety risk in lithium-ion batteries (LiBs). External triggers such as high temperatures, mechanical abuse, or internal short circuits (ISCs) can initiate TR, often resulting in sidewall rupture, which may escalate to catastrophic battery pack failure. In this study, we developed and applied high-speed synchrotron imaging techniques to investigate sidewall rupture mechanisms in LiBs subjected to different triggering scenarios. Using <i>in situ</i> 4D tomographic imaging, we visualized the dynamic evolution of sidewall rupture with high spatial and temporal resolution. The results revealed distinct failure behaviors linked to each trigger, underscoring the complex and condition-specific nature of sidewall breach and battery failure. These insights highlight the critical importance of implementing tailored safety strategies across diverse applications. Our findings demonstrate the powerful potential of synchrotron high-speed tomography as a diagnostic tool for advanced safety testing and cell qualification.

As the National Aeronautics and Space Administration (NASA) transitions to exploration missions beyond low Earth orbit (LEO), a plethora of Human Health and Performance (HH&P) risks and knowledge gaps must be addressed to ensure safe and successful execution of extravehicular activities (EVA) during missions to the Moon and Mars. Some studies, such as those focused on understanding injury mechanisms in the suit, require access to high-fidelity, pressurized space suits and/or mockups; however, many EVA objectives related to HH&P do not necessarily require a full pressurized and/or gravity-offloaded space suit. Examples of these types of studies may include developing and testing novel EVA informatics and decision support systems, biomedical monitoring systems, and assessment of physical and cognitive responses to EVA tasks, timelines and training. Additionally, access to NASA space suits and/or mockup space suits can be limited and costly. Thus, the NASA EVA and Environmental Physiology Laboratory (EEPL) developed the Hybrid Space Suit Simulator (HS3). The primary goal of the HS3 project was to create a low-cost, unpressurized space suit simulator for use as an EVA research tool with modular capabilities to provide physical and cognitive workload approximations as required by specific study aims during EVA simulations. A space suit simulator like HS3 significantly simplifies and reduces overhead for EVA analog testing while providing consistent, quantifiable simulation quality and fidelity. This report describes the design, development and characterization of the HS3 during simulated EVA as a modular, customizable research tool with integrated human physiological sensors to address human health and performance EVA knowledge and technology gaps.

SummaryThis study evaluated lumbar spine bone mineral density and trabecular bone score in ISS astronauts using DXA under 3 different countermeasure regimes. ARED + bisphosphonate maintained BMD, while both ARED and ARED + bisphosphonate preserved TBS. TBS supplements DXA assessments of spaceflight effects on bone health.PurposeTo assess the utility of lumbar spine (LS) bone mineral density (BMD) and trabecular bone score (TBS) from scans using dual x-ray absorptiometry (DXA) performed in astronauts before and after spaceflights aboard the International Space Station (ISS). The influence of mission duration and of inflight countermeasures on changes described by BMD and TBS was also evaluated from longitudinal DXA tests performed postflight.MethodsPreflight and postflight DXA scans, from which BMD and TBS were acquired, were performed from 51 crewmembers: 41 men (mean age ± SD, 48 ± 5, range 37–56 years) and 10 women (mean age ± SD, 44 ± 3 years, range 41–50 years) who flew on missions of ~ 6 months duration. Participants were categorized into three groups: Pre-ARED (advanced resistive exercise device) (n = 24), ARED (n = 20), and ARED + bisphosphonate (alendronate 70 mg/week) (n = 7). Longitudinal DXA scans were obtained from 311 individual astronauts (266 men, 45 women; age range, 41–80 years) from November 1999 to February 2014 to assess trends following spaceflights, categorized as short-duration (less than 1 bone remodeling cycle [BRC]) and long-duration (> 1 BRC).ResultsOnly the ARED + bisphosphonate group was not different from preflight BMD (+ 2.8%, p = 0.1). Regarding TBS, both the ARED and ARED + bisphosphonate countermeasure groups were not different from preflight (+ 0.2%, p = 0.7; −1.5%, p = 0.3). Longitudinal trends of TBS and BMD from short-duration missions revealed declining trends in men. In terms of long-duration missions, there tended to be declining trends in spine BMD and TBS when plotted as a function of age.ConclusionDXA can detect how various in-flight countermeasures and the length of mission affect the lumbar spine that is enhanced with the addition of TBS.