The increasing population of CubeSat in low Earth orbit (LEO) has intensified concerns over orbital debris, creating a need for efficient, lightweight, and propulsion-free end-of-life disposal strategies. Conventional passive de-orbit methods primarily rely on drag augmentation to accelerate orbital decay but do not reduce spacecraft mass, limiting improvements in the area-to-mass ratio and overall disposal efficiency. This study proposes a novel dual-function passive self-disposal system for a 1 U wood-based CubeSat that employs a single deployable aluminum-coated Kapton HN solar reflector to perform two sequential end-of-life functions. First, the reflector concentrates solar radiation to induce controlled thermal ablation of selected spacecraft components, thereby reducing the spacecraft mass. Subsequently, the same reflector functions as a passive drag sail to increase the effective aerodynamic area and enhance atmospheric drag, resulting in faster orbital decay without the use of propulsion. The proposed concept is evaluated through orbital decay simulations under representative space weather conditions and validated using Monte Carlo uncertainty analysis. The results show that the proposed approach reduces the de-orbit time to approximately 110, 20, and 10 days under low, medium, and high solar activity conditions, respectively, representing a substantial improvement over conventional passive drag-sail approaches while maintaining good agreement between deterministic and stochastic analyses. The proposed dual-function solar reflector provides a simple, lightweight, and energy-efficient solution for CubeSat end-of-life disposal and contributes to future space debris mitigation and long-term orbital sustainability.
This paper presents the acceleration measurements recorded by RadNano Infinity dosimeters used during the Axiom Mission 4 (Ax-4) from 25 June to 15 July 2025. The instruments recorded data throughout the complete spaceflight, including spacecraft launch, the entire mission aboard the International Space Station, and the return to Earth. The acceleration magnitude recorded during spacecraft launch reached 4.6 g, representing the peak acceleration of the mission. The maximum acceleration upon returning to Earth was 4.3 g. Ten autonomous instruments accompanied astronauts and payloads throughout the complete spaceflight, two of which were worn during selected astronaut activity periods on the ISS. This distributed configuration enabled phase-resolved documentation of vehicle-dominated and wearer-local acceleration histories using the same measurement platform. The mean acceleration magnitudes during the analysed active periods were 0.014 g and 0.013 g for the two monitored astronauts. The wearable accelerometers indicated typical acceleration magnitudes on the order of 0.01 g during active periods, reflecting the astronauts’ kinematic micro-movements.This study provides rare phase-resolved operational reference measurements for human spaceflight and demonstrates the feasibility and limitations of autonomous wearable and payload-borne acceleration monitoring under actual mission conditions. The findings of this paper may serve as an important reference for the planning of future space missions. Future investigations could correlate these results with astronaut physiological data to better understand the health impacts of hypergravity and microgravity conditions during spaceflight.
Autonomous Mars surface habitats will operate under delayed oversight, constrained resupply, persistent scarcity, and high crew dependence on life-support systems. Although habitat architectures increasingly address power, life support, in-situ resource utilization, and logistics, the governance mechanisms that determine who may allocate scarce resources, activate emergency authority, resolve disputes, and authorize expansion are rarely specified as mission-assurance controls. This paper introduces the Mars Community Planning Protocol (MCPP), an operations-oriented protocol for converting settlement governance into verifiable artifacts for autonomous surface habitats. MCPP operates at two linked levels: habitat-level operational governance for life-support scarcity and settlement-scale governance maturation for expansion from outpost to more complex surface communities. The protocol specifies phase gates tied to readiness evidence, functional zoning rules for protected habitable volume, service-spine access, contamination control, and recovery space, a Life-Support Commons Charter for air, water, and power allocation, and a compact metrics dashboard covering governance performance, resilience, habitability, and justice/legitimacy. The contribution is procedural: MCPP does not claim empirical validation or prescribe a political model. Rather, it defines artifact–owner–verification relationships that can be tested through tabletop drills, analog deployment, and simulation-coupled CONOPS evaluation. By making governance readiness a condition for expansion, MCPP provides a mission-assurance pathway for reducing social and operational failure modes in early Mars habitats.
Lunar surface operations will rely on delayed ground supervision, creating a safety-relevant mismatch between local hazard conditions and the state available to remote decision support. This paper provides a timing-sensitive analytical method for evaluating that mismatch through two coupled constructs: hazard drift, defined as divergence between the current local hazard-intensity index and its delayed representation, and decision fidelity, defined as the degree to which a judgment formed on aged information still matches local conditions at execution. These constructs are integrated into a temporal misalignment metric and examined using parametric Monte Carlo simulation across low-tempo, transitional, and hightempo operational regimes. Results show that supervisory relevance degrades systematically as communication delay and hazard tempo increase together, even in the absence of hardware failure or procedural deviation. An illustrative lunar EVA scenario demonstrates that short delays may remain tolerable in slower tasks but become safety-consequential when local conditions evolve more rapidly. The paper provides a compact mission-assurance method for identifying when delayed supervision no longer provides a sufficiently current basis for risk-informed operational support during lunar surface operations. (c) 2026 International Association for the Advancement of Space Safety. Published by Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
Understanding the fragmentation of modern spacecraft materials is critical for accurate orbital debris modelling. The DebriSat laboratory hypervelocity impact experiment was designed to provide representative data on these materials, with carbon-fibre reinforced polymer (CFRP) as the focus of this study due to its increased use in satellites and its disproportionately high fragment count. Analysis of DebriSat fragmentation data demonstrates that CFRP is the dominant contributor to fragment count despite its relatively small contribution to mass. The current estimate of the collected fragments greater than 2 mm is more than 325,0 0 0. As of February 19, 2025, over 220,0 0 0 fragments had been recorded in the Debris Characterization System (DCS). Of these, 126,642 had been assessed for material type(s), shape, and other basic characteristics, with 78,749 identified as primarily CFRP, representing 62.2% of the assessed population. Within the measured subset of fragments with dimensional data from imaging (65,582 fragments), 38,967 were identified as CFRP, corresponding to 59.4% of that dataset. This value is within 3% of the overall assessed percentage, showing that the CFRP fragment count is closely represented in the measured dataset used for size and shape distribution analyses. Results show that CFRP fragments are strongly skewed toward the sub-centimetre regime, with 63.1% falling in the 2-10 mm range. CFRP also overwhelmingly produces needle and plate geometries, reflecting its brittle, layered fracture behaviour. Although CFRP accounts for about 62.2% of the total fragment count within the assessed population, it contributes only 3.28% of the measured mass within the massed population. This disproportionate behaviour underscores the need to incorporate CFRP fragmentation into updated breakup models to ensure accurate orbital debris risk assessments. (c) 2026 Published by Elsevier Ltd on behalf of International Association for the Advancement of Space Safety.
Space-based Automatic Identification System (AIS) reception offers an effective solution for maritime surveillance beyond the coverage of terrestrial networks. This paper presents the design and in-orbit validation of an SDR-based AIS receiver onboard the UM5Sat-Ribat nanosatellite, the first Moroccan 3U university CubeSat. The originality of this work lies in demonstrating a reconfigurable SDR payload for AIS reception on a university nanosatellite platform. Several in-orbit experiments were carried out over different maritime regions, and the results confirmed the successful detection and decoding of AIS messages from multiple vessels under real orbital conditions. The average detection probability was estimated to range from about 12% to 25%, based on a comparison between decoded vessels and estimated maritime traffic. The results also highlighted key challenges of space-based AIS reception, including Doppler shift, packet collisions, and varying traffic density. Overall, the UM5Sat-Ribat mission demonstrates the feasibility of low-cost SDR-based AIS reception from space and confirms the potential of reconfigurable na nosatellite payloads for maritime monitoring.
The South Korean orbital launch vehicle Nuri, which was successfully launched in 2022 and 2023, has the capacity to carry 3.3 tons to LEO. The launch vehicle is powered by a similar kerosene gas generator cycle engine as the Soyuz and the Falcon 9, which are currently used successfully as crewed launch vehicles, and are considered suitable for use as a crewed launch vehicle once its reliability is improved. According to South Korea's latest space plan, it aims to develop a crewed space launch vehicle by 2045 to put astronauts into LEO. SpaceX launched its Falcon 9 in 2010, but it took another 10 years to get astronauts aboard, and Russia took a whopping 16 years to get astronauts aboard its Soyuz 2.1a after the first launch of the Soyuz 2 in 2004. India has yet to conduct a successful crewed flight test, 20 years after it began development of its crewed spacecraft Gaganyaan in 2007. Therefore, South Korea's crewed space launch vehicle plan should begin in 2025, so that it can put people into orbit by 2045.To convert the KSLV-II Nuri launch vehicle to a crewed launch vehicle, we studied the launch success rate, number of launches, development time, and technology required for a crewed launch vehicle. We also studied how crewed missions could be expanded using South Korea's next-generation launch vehicle (KSLV-III), which is being developed with the goal of an uncrewed lunar landing by 2032.
To achieve optimal aerodynamic performance across a wide speed range, a morphing-configuration waverider scheme was proposed, and its energy-saving effects were investigated. Using CFD simulations, an aerodynamic database was developed to evaluate different vehicle configurations. Subsequent analysis showed that the morphing configuration significantly outperforms static designs across a wide speed range. For a flight mission involving gliding followed by cruising, trajectory optimization was performed using the pseudospectral method. Comparative analysis of simulation results under multiple operating conditions for different configurations confirmed the significant energy-saving effects of the morphing aircraft in missions requiring wide speed and altitude ranges.Taking a flight mission with an initial altitude of 50 km, initial speed of 10 Ma, initial flight path angle of -3°, final altitude of 25 km, final speed of 6 Ma, and final flight path angle of 0° as an example, the morphing configuration saved 43.86% and 52.78% fuel when compared with fixed configurations at 5 Ma and 8 Ma respectively.
Increasing orbital debris density presents a growing threat to the operational integrity of the space environment, particularly in Low Earth Orbit (LEO). A critical challenge lies in the observational gap for millimeter-sized debris. Debris of this size remains undetectable by current radar-based tracking systems and carries sufficient kinetic energy to damage or disable satellites with which it collides. In-situ detection methods may address this measurement gap. This study investigates the feasibility of detecting small debris impacts by analyzing the resulting perturbations in satellite altitudes. A geometric assessment of orbital mechanics reveals that high-inclination orbits are more susceptible to high-velocity impacts due to their greater relative speeds. Debris flux, velocity, and directional statistics are obtained from the NASA orbital debris engineering model (ORDEM) analysis across a range of LEO altitudes and inclinations. Using momentum transfer principles, conservative estimates of the delta-v imparted by debris impacts are calculated and translated into expected changes in orbital altitude over different orbits in LEO from ORDEM simulations. The results indicate that impacts from aluminum debris in the 1–3 mm diameter range can produce detectable altitude changes in small satellites, such as CubeSats or other low-mass platforms, demonstrating that the proliferation of small satellites provides a promising avenue for passive debris flux measurement in space.
The increasing density of orbital debris elevates collision risk and drives the need for autonomous systems capable of operating under strict safety and sustainability constraints. This work introduces the Space Robotics and Sustainability (SRS) architecture, a deterministic and governance-aware decision system that embeds sustainability metrics and regulatory constraints directly within the maneuver-selection loop. Through this formulation, sustainability principles become measurable decision variables that govern maneuver admissibility, prioritization, and execution during delay-tolerant operations. This work also introduces the PAG AI framework, which is composed of Physical AI for constraint-aware interaction with orbital dynamics, Agentic AI for distributed decision-making and traceability, and Governance-Aware AI for embedding regulatory compliance within the control loop. The SRS architecture incorporates two complementary decision mechanisms to operationalize the PAG AI framework. The Sustainability Impact Score (SIS) evaluates candidate maneuvers using multi-criteria indicators, including mission safety, propulsion efficiency, regulatory compliance, and time performance. The Operational Relevance Index (ORI) prioritizes agent activation according to mission context, uncertainty, and risk contribution, enabling resource-aware coordination within the decision pipeline. These mechanisms produce structured and traceable autonomous behavior aligned with operational policies. Validation on the spacecraft near-distance rendezvous problem demonstrates that the SRS architecture generates stable approach trajectories with controlled velocity profiles and consistent adherence to safety constraints. Comparative evaluation against conventional guidance strategies highlights a distinct decision paradigm in which maneuver selection incorporates governance compliance and sustainability-driven evaluation as primary decision criteria. Monte Carlo simulations under uncertain initial conditions confirm high mission success rates and improved sustainability-oriented performance relative to nominal baseline strategies, while preserving full decision traceability through structured logs. The proposed architecture provides a foundation for policy-compliant autonomous systems in orbital operations. Its modular nine-layer structure supports scalability toward more complex debris-removal scenarios, enabling the integration of robotic autonomy, sustainability principles, and governance-aware decision-making in future space missions.
Spacefaring vehicle and habitation design will need to support the extravehicular activity (EVA) excursions required to establish sustained presence on the Moon and Mars. A crucial technological design advancement towards this goal is the use of a lower pressure, higher oxygen exploration atmosphere (EA) that enables high efficiency EVA, rather than the current terrestrial atmosphere employed. Unfortunately, with a higher oxygen environment come fire safety concerns that will need to be addressed. To aid in decreasing both decompression sickness and fire risks during exploration missions, the use of other mitigations such as elevated suit pressure are being considered. The final sustained Artemis architecture is not yet determined but will need to start with EA that optimizes engineering solutions to best ensure crew safety and mission assurance.
The recent discovery of 3I/ATLAS, the third interstellar object (ISO) observed to date, has naturally sparked a debate regarding its nature: is it a comet, or a potential technosignature of an alien civilization? This paper, however, focuses not on the object’s nature, but on a critical lesson that should be learned from its passage through the Solar System. It is argued that, due to the short notice such visitors provide, their high velocities, and their potentially massive nature, the hazards associated with potential Earth impacts could be greater than those posed by a comparable-sized, Sun-bound object. This heightened risk necessitates the formal consideration of the hazard posed by ISOs and potential mitigation strategies. The short notice an ISO may give before an impact renders a long-lasting, well-planned deflection mission, like DART, unlikely to be feasible and ill-suited to address such a threat. Given the short reaction time, nuclear warheads and vehicles operating with nuclear rocket engines may be the best-suited options to address potential ISO threats (also Sun-bound large objects detected late on their way toward Earth could be mitigated this way), yet the Outer Space Treaty’s ban and prevailing international disputes render us, as a planetary civilization, highly unprepared and vulnerable to any potential imminent ISO impact hazards.
Near-Earth Object (NEO) impact probability was formulated as a censored inference problem over an unknown population, rather than as a survival analysis restricted to already-discovered objects. Discovery was treated as an exposure-driven stopping time, and impact was represented as a latent competing risk, so that undiscovered bodies contributed explicitly to forecast uncertainty. A hierarchical Bayesian framework was constructed to couple discovery counts, survey exposure, and time-to-impact hazard within a single model. Annual discoveries were modeled by a Negative-Binomial exposure process to capture over-dispersion under variable survey performance, while impact timing was described using a parametric hazard component. Robust estimation based on the density-power-divergence principle was applied to stabilize inference under irregular observing conditions. Posterior inference was obtained using Hamiltonian Monte Carlo. Future impact-hazard probability over a specified horizon was then forecast by propagating posterior uncertainty through posterior predictive simulation under projected exposure trajectories, yielding predictive distributions and credible intervals for long-term planetary-risk assessment. Robustness is further assessed through a probabilistic sensitivity analysis that treats observational exposure as an uncertain quantity, demonstrating stability of population-level impact inference under realistic exposure mismeasurement. The framework was applied to NASA CNEOS and Minor Planet Center data from 2015 to 2025 across the Aten, Apollo, and Amor classes, enabling exposure-consistent forecasting and sequential updating as new discoveries become available.
Additive Manufacturing (AM), a rapidly maturing manufacturing technology, has garnered increased adoption amongst rocket engine development programs as processes and material databases continue to mature. While subtractive manufacturing achieves complexity through multi-part assembly, AM offers the ability to produce complex geometries in fewer parts, reducing assembly operations and ultimately enhancing affordability. Despite these advantages, AM introduces material property variation from process-dependent effects that requires analytical characterization to reduce reliance on Test-Fail-Fix (TFF) cycles during physical qualification. This challenge is especially important when working with nickel-based superalloys such as Inconel 718 and 625, which must maintain their performance in the high-temperature and oxidative environments typical of chemical rocket propulsion applications.To address AM uncertainties, probabilistic models in combination with model-based systems engineering (MBSE) tools have emerged as an alternative to traditional deterministic design approaches. Notably, efforts dedicated to the conversion of traditional Factor of Safety (FoS) methods into a probabilistic realm highlight the potential that lies in such a shift. For aerospace applications, it is critical to consider the impact AM can have on fatigue-driven damage mechanisms, including crack initiation and propagation that lead to structural failure. If unanticipated fatigue-driven failure occurs on a test stand or during flight operations, severe consequences including the loss of test infrastructure, loss of mission, or even loss of crew members can occur. Probabilistic models that account for uncertainties in AM materials and processes present a possible solution to mitigating the risk of these failures. In support of this effort, this work aims to develop an analytical framework to assess how AM techniques such as Laser Powder Bed Fusion (L-PBF) and Laser Powder Directed Energy Deposition (LP-DED) affect fatigue characteristics of materials used for large-scale propulsion applications. This framework will be demonstrated in a reliability driven, model-based affordability environment currently being developed to promote consideration of reliability early in the design and development phase. Using a first-principles approach, this analysis seeks to improve understanding and inform design decisions by projecting fatigue life and crack growth rates early. As a foundational element for early lifecycle TFF susceptibility assessment, this framework enables early quantification of fatigue capacity for AM materials and processes that helps inform material-process selection and test planning to reduce critical failure likelihood when uncertainties are significant.
As commercial space launch operations expand further in Australia, identifying, understanding, and mitigating the risks associated with launch overflight is essential to ensure public safety. Historically, launch facilities have been sited to minimise the risk to the public by positioning for launch over the ocean where no permanent population centres are present. The risks from launch activities are greatest closest to the launch point, and significant focus is generally placed on this area. However, risk of failure is still present until the end of the propulsive portion of the flight and later failures can result in debris falling a significant distance from the launch point. The Australian population is concentrated on the coast limiting launch site options due to risk close to the launch point. Launching from and over Australia's vast and sparsely populated inland areas presents both opportunities and challenges. While conventionally uninhabited inland areas may lower risk from failures early in the trajectory, the presence of remote communities, critical transport infrastructure, and protected environmental sites within the flight corridor introduce greater complexities in ensuring public safety. This paper explores the application of Conditional Expected Casualty (CEC) as a key metric to assess, quantify, and manage the consequences of overland launches from Australian launch sites. CEC is not treated as a complete measure of public risk; rather, it quantifies expected casualties given the occurrence of specified failure events. Simulations of a generic small expendable launch vehicle, developed by analysing parameters such as population density, launch vehicle performance, failure trajectories, debris survivability, and overflight timing give insights into how the mission design can be adapted to provide a conservative measure of conditional expected casualties, given a failure. The findings provide valuable insights, not only for launch service providers, but also for launch site providers and regulators. Using CEC as a decision-making tool can be crucial in enabling sustainable launch operations and maintaining operational feasibility, all while sustaining public trust and regulatory approvals. Furthermore, a deeper understanding of this measure allows Australia's growing space sector to balance operational efficiency with commercial growth, without compromising public safety. (c) 2026 International Association for the Advancement of Space Safety. Published by Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
Given the rapid proliferation of space objects in Earth orbit, today, Space Situational Awareness (SSA) has become a critical and foundational infrastructure for ensuring safe and sustainable space activities, as well as tackling space traffic and space debris issues. Many countries, including emerging space countries and private companies, are engaging in their SSA activities. Information sharing among these multiple and diverse SSA activities is required since sharing SSA information can improve the accuracy and effectiveness of SSA, and space operators need to exchange information to avoid potential collisions. Open, free, and timely sharing of SSA information is desirable, although it is challenging due to security considerations, commercial interests, and differences in data formats. Further, the global coordination of SSA remains fragmented. Therefore, we need to consider establishing the appropriate framework for broader SSA information sharing, and the question is how. Earth observation (EO), which have strategic and commercial implications and share common challenges in information sharing, could provide a practical reference. In this area, a comprehensive multilateral EO coordination framework has been established to build the global Earth observation system of systems by networking multiple open and free EO services. Satellite images of areas impacted by disasters are provided free of charge in a timely manner through the international framework. Therefore, this paper aims to analyze possible approaches to developing the international framework for SSA information sharing with reference to the lessons learned from EO. The Author examines the development process and features of existing international EO cooperative frameworks, namely Committee on Earth Observation Satellites, Group on Earth Observations, the International Charter Space and Major Disasters, and Sentinel Asia, to extract the approaches that facilitated cooperation among space actors, with a particular focus on information sharing. Based on the analysis, the Author discusses challenges and policy options, including concept models, for the future international framework of SSA cooperation. The studied EO frameworks achieve broader information sharing by applying a system of systems and best-effort approach with minimal mandatory requirements, while respecting members’ policies, as well as autonomy and commercial considerations. Additionally, the contributions of leading SSA actors, greater involvement of private sector along with an interface that facilitates timely coordination and information exchange, are crucial. A combination of best practices of EO frameworks is the recommemded approach for the future cooperative framework for SSA.
Astronaut training has undergone significant transformation since the early days of human spaceflight, evolving in response to technological advances, changing mission objectives, and the increasing complexity of international cooperation. This paper provides a historical overview of astronaut training, tracing its development from the early Space Race era to the present day. It examines how initial training programs, largely focused on military pilots and short-duration missions, have expanded to encompass a broader range of skills, disciplines, and professional backgrounds. The paper compares astronaut training approaches across six major spacefaring entities: NASA (United States), Roscosmos (Russia), ESA (Europe), CNSA (China), JAXA (Japan), and CSA (Canada), highlighting both commonalities and differences shaped by national priorities, organizational culture, and mission requirements. In addition, the paper discusses the emergence of commercial human spaceflight and its impact on training philosophies, regulatory frameworks, and safety considerations. By outlining historical trends and current practices, this paper provides a comprehensive overview of astronaut training in the new era of spaceflight and identifies key factors influencing its continued evolution.
Reliable radiation effects testing is a prerequisite for safety and mission assurance in aerospace and high-altitude systems, yet the role of ISO/IEC 17025 accreditation in strengthening the technical validity, traceability, and reproducibility of such testing remains insufficiently operationalised for laboratories working with total ionising dose (TID) and single event effects (SEE). This study analyses the accreditation pathway for ionising-radiation effects testing in aerospace electronics under ISO/IEC 17025 and SISMETRA guidance, combining (i) documentary analysis of standards and institutional quality records with (ii) semi-structured interviews with personnel involved in irradiation testing, dosimetry, metrology, and quality management. The results consolidate the primary drivers for accreditation, including technical credibility, interoperability, and risk reduction, as well as the dominant barriers, such as licensing constraints, high infrastructure and calibration costs, competence retention, and sustained audit workload. Based on the integrated evidence, the paper proposes a staged implementation roadmap that maps the end-to-end irradiation workflow (dosimetry, pre-irradiation characterisation, irradiation execution, post-irradiation characterisation, and reporting) to the ISO/IEC 17025 technical requirements most critical to radiation testing, including traceability, uncertainty evaluation, method validation, data integrity, and assurance of validity. Beyond compiling standards, the paper provides an operational workflow-to-requirements mapping and a prioritised set of critical control elements to support transferable implementation of ISO/IEC 17025 in TID/SEE testing. The findings highlight the relevance of international standards and their positive impact on scientific, economic, and social spheres while exposing technical challenges, high costs, and bureaucratic barriers. In this context, innovations linked to Industry 4.0 emerge as a potential solution to enhance the accreditation process.
Space safety is a multidisciplinary field encompassing the protection of human life, the preservation of orbital and terrestrial environments, and the safeguarding of space infrastructure on which modern society increasingly depends. This article provides a comprehensive overview of the current state of the field, organized around its principal domains. It begins by establishing the conceptual foundations: the nature of safety as the management of risk to an acceptable level, the distinction between objective safety and safety perception, and the diversity of safety fields, from crew protection aboard human-rated vehicles, to public safety during launch and re-entry, to the growing threats of orbital debris and environmental risk from space operations. The article reviews the safety record of human spaceflight, contextualizing historical fatality statistics and identifying the organizational lessons that transformed NASA's approach to safety governance following the Apollo 1, Challenger, and Columbia accidents. A dedicated section synthesizes the principles of system safety engineering and management i.e., risk-based design, hazard analysis, failure tolerance/avoidance, safety review panels, and technical authority, together with the institutional frameworks needed to apply them in commercial programs, including the case for a regulated self-policing Space Safety Institute modeled on analogous institutions in maritime (Classification Societies) nuclear and offshore energy sectors. Subsequent sections address launch safety, from ground operations and flight termination systems through the emerging use of autonomous systems, and the growing threat of orbital debris, including the risk of debris instability in certain low Earth orbit bands. Concurrently, the active space objects population is growing exponentially. The emerging satellite mega-constellations have made traditional human-in-the-loop collision avoidance unsustainable, driving the use of autonomous onboard avoidance systems, while the presence of uncoordinated military assets in congested orbits points to the need for a density-triggered coordination framework applicable to all operators. Re-entry risks to public on ground and to aviation are examined in detail, including the challenge of designing satellites to demise and the underappreciated atmospheric impacts of large-scale constellation re-entries. The article concludes with an analysis of space search and rescue, from the existing framework for launch abort recovery through the demanding technical and governance requirements of on-orbit and lunar rescue operations. Across all domains, the article emphasizes that space safety is an international responsibility requiring harmonized standards, interoperable systems, and coordinated governance structures commensurate with the global nature of the risks involved. (c) 2026 International Association for the Advancement of Space Safety. Published by Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.
