Journal of Space Safety Engineering最新文献

Morgan Stanley forecasts the space industry to top 1 trillion dollars by 2040. Of these 1 trillion dollars, 1.5 billion dollars are expected to be the contribution of the space situational market alone.

Satellite operators are already paying the price of space debris. Current approaches for collision avoidance and space traffic management face serious challenges, mainly: (1) Insufficient data and endangered autonomy of action in space; (2) A high number of false alerts and a large uncertainty; (3) Lack of scalability and automation for an increasing number of assets.

This paper explores the potential of AI for Space and presents some of the advances made by Neuraspace in Space Traffic Management, including the analysis of conjunction data messages (CDMs), predicting uncertainties, and risk classification, and the economic benefits of new approaches.

Further, the paper addresses the need for a more active role of the private sector and an evolution of the role of the public sector to foster space sustainability and support the growth companies leading this effort.

The Ethiopian remote sensing microsatellite, weighing 65 kg, was successfully launched into sun-synchronous orbit at an altitude of 628 km in 2019. The satellite has a three-year lifespan and employs a maneuver that minimizes the orbit perigee without adjusting the orbit apogee, resulting in an eccentric disposal orbit, with the perigee altitude selected to ensure re-entry into the Earth’s atmosphere within 25 years. This study presents an overview of the ETRSS-1 satellite system, including its subsystems alongside the hardware utilized during their development, as well as an analysis of its on-orbit performance. Furthermore, the spacecraft’s electro-optical multispectral camera and its ability to capture remote sensing data while adhering to appropriate operational constraints, as well as its imaging mission techniques, various types of failure modes, and anomaly detection detection techniques, will be investigated.

In 1972, the international community established a regime of liability for damages occurring in outer space based on ‘fault’. Fifty years later, the congested and polluted reality of the space environment has limited dramatically its effectiveness. Only in very few instances, filing a claim under such regime can reasonably ensure compensation to an injured satellite operator. The present paper describes different study cases where resorting to a fault-based liability claim appears problematic. Based on real conjunction assessment alerts, the authors look into various hypothetical scenarios from the perspective of a fictitious satellite operator, whose spacecraft was damaged by an accidental collision in orbit. The aim is to analyse the effective observability over orbital collisions involving small satellites and space debris (attributable or not) and to evaluate the real chances of obtaining compensation, from the operational and legal points of view. At the centre of this study, therefore, is the evaluation, in fact and in law, of the solidity of a potential claim against the perpetrator of the harm. To that end, the discourse takes into consideration the legal difficulties that are generally connected to fault-based liabilities in international law.

The definitional vagueness of the term ‘fault’, the necessity to identify a fault-standard, the proof of failure in the performance of a duty of care, are all elements to consider for filing a claim under the liability regime of 1972.

However, next to them, the space environment poses additional hurdles with regard to facts and evidence. Satellite operators do not always have the technological instruments to retrieve all the information related to orbital events, such as collisions. Moreover, a complete observability over in-orbit events can be hard to reach for several classes of spacecraft (e.g. small, nano- or pico-satellites). This is especially troublesome for establishing one of the essential elements of ‘fault’: the so-called “chain of causation”. The authors will present their views on how the uncertainties posed by the liability regime of 1972 can be dealt with from a legal and from a technical perspective. In addition, several possible legal solutions and recommendations for the upcoming years of in-orbit operations and space traffic management will be proposed at the end.

In the current context of the multiplication of space actors and orbital projects, the French space ecosystem is fully aware that the challenge ahead will be to ensure the safety and sustainability of space activities. Within the framework of France national law governing space operations and its Technical Regulation, CNES Space Safety Office has been working since 2020 to implement new technical requirements adapted to the NewSpace for the control and return to Earth of space objects.

The process of elaboration of these new technical requirements is broken down into several steps: identification of the problematics/themes, translation of these problematics into macroscopic needs and then into specific technical requirements, justification by appropriate studies, implementation through handbooks or tools, and definition of an applicability milestone.

On the one hand, the technical aspects are assessed thanks to the support of CNES technical services in the framework of specific working groups, studies ordered by the Space Safety Office, or analysis of international publications. On the other hand, the operators’ views and their programmatic constraints are taken into account – in parallel with the monitoring of international standards – in order to maximize the operators’ acceptance and to minimize the risks of competition bias for the French ecosystem while not losing sight of the objective of safety and sustainability in space. In this context, the awareness of these private actors and their consultation are at the heart of the process of elaborating new technical requirements and their implementation schedule.

There is growing concern that collision risk in low Earth orbit is inadequately managed, necessitating new strategies. Based on discussions held at a multistakeholder workshop organized by EPFL in May 2021, this paper presents some challenges, or governance deficits, in the assessment and management of collision risk, and offers some paths for improvements in both domains. Addressing the governance deficits will require enhanced collaboration between states and between public and private actors.

While there is a need to improve risk assessment and conduct thorough cost-benefit analyses of management strategies, achieving a complete picture is elusive, given the complexity of the problem and the range of response strategies available. However, the lack of a complete picture should not be a reason to postpone action, as sufficient information to make decisions regarding some management policies is available. Adopting a multidimensional approach and focusing on measures that have the potential for rapid improvements would help secure stakeholder buy-in and lay the groundwork for pursuing strategies that will likely be the most cost-effective in the longer term.

In 2018, the US National Space Council released Space Policy Directive-3 (SPD-3), which instructed relevant US government agencies to begin re-assigning many aspects of space traffic management (STM) and space traffic coordination (STC) serving non-military US space operators. This was identified as a ‘whole of government’ approach, and the organization identified to lead many of the efforts was the National Oceanic & Atmospheric Administration (NOAA) Office of Space Commerce (OSC), in the US Department of Commerce (DOC). The US Congress, in Public Law 116–93, Consolidated Appropriations Act, 2020, legislation directed that the Secretary of Commerce contract with the National Academy of Public Administration (NAPA) to study the Trump Administration's proposal. The NAPA study affirmed OSC would be best suited. Congress also mandated that OSC accomplish an important first step: assemble an Open Architecture Data Repository¹ (OADR) prototype to demonstrate the efficacy of the approach and architecture.

OSC, along with The Aerospace Corporation, MITER, MIT Lincoln Laboratories and the University of Texas-Austin, architected and assembled a working prototype in 2021. The team obtained two-months of data from the US Space Surveillance Network (SSN), along with data from commercial space surveillance data providers and satellite operator ephemerides. Using the prototype, the authors analyzed the data, identified potential satellite conjunctions, calculated probabilities of collision, and generated Conjunction Data Messages (CDMs). The team compared the results to existing operational systems, with good agreement. OSC and their partners demonstrated the OADR prototype results to the Congress, as funded and directed by Public Law 116–260, the Consolidated Appropriations Act of 2021. This paper describes some of the background and rationale for the prototype, goals and derived requirements of the prototype, the architecture, software deployed, data utilized, conjunction analysis results, comparison of the prototype's results with existing operational US government systems, and possible next steps for the OADR.

Determining the long-term corrosion fatigue strength of structural materials in service conditions is one of the most significant problems of the design engineer. Synergistic interactions between mechanical fatigue effects and environmental factors may be more harmful than the total effects of each mechanism working alone. Current understanding is inadequate to handle life estimate with a good physical foundation, from the onset of localized corrosion (such as pitting) through the estimation of fracture propagation. Considering that a corrosion phenomenon is a time-dependent event, the extended fatigue life of the components, exposed to a corrosive environment, is a key concept to comprehend to design safely against corrosion and ultralong life fatigue failure. Utilizing In-situ (or ex-situ) ultrasonic fatigue testing, the ultralong-life fatigue and corrosion behavior of structural materials in a very high cycle regime could well be studied. In this article, the benefits of ultrasonic fatigue testing, including screening tests' efficiency, acceleration, reliability, and the research of fatigue and corrosion fatigue behavior in very high cycle regimes are mostly described. The focus of this state-of-the-art review paper will be on the significance of corrosion pits and the interaction between mechanical cycling and corrosion pitting in the very high-cycle corrosion fatigue fracture initiation stage. The paper starts with an introduction to various mechanisms of corrosion fatigue. It then continues with a general description of very high cycle fatigue (VHCF) and very high cycle corrosion fatigue (VHC-CF) and then continues with the characterization of VHCF and VHC-CF of conventionally and additively manufactured materials. This review article also analyses available VHC-CF crack models in both conventionally-fabricated and additively manufactured metallic materials. Finally, a comprehensive summary of the needs, importance, and applications of VHC-CF has been provided in the current review paper.

ESA's Space Debris Office (SDO) provides support and recommendations for the on-ground risk assessment at the satellite's end of life (EOL) to internal ESA missions as well as external partners. The support covers missions in Low Earth Orbit (LEO) and highly eccentric orbits (HEO), but also special cases such as a re-entry of interplanetary missions. While for LEO and Geostationary orbits (GEO), guidelines for disposal in terms of natural decays and graveyard orbit are available, HEO orbits require tailored strategies to guarantee limited interference with the protected regions and a safe re-entry. The present works aims to provide an overview and reflection on the current approaches for the end-of-life strategies for mission in HEO orbits, accounting for the main uncertainties.

Space vehicles travel long distances during launch or re-entry before reaching their destination. To reduce the risk to noninvolved third parties in the case of a non-nominal event, current best practice is to assure large parts of the ascent or decent flight phase are above open water or at least over regions with low population density. Nevertheless, at any one time the vehicle trajectory / instantaneous impact point may cross countries other than the one the launch took place in. This can pose a risk to the country's population and infrastructure and it has to be ensured that their safety regulations are met. The need to consider multiple risk and safety policies of different states, complicates and enlengthens mission planning. International harmonization of handling launch and re-entry risks in spaceflight would simplify the access to space and the required planning and certification processes. Against the background of an increasing frequency of space operations the required safety measures have to be evaluated regarding their impact on air and sea traffic. When considering the consequences caused by such measures, for example in the form of extended flight trajectories, these contrast with the goals of air traffic that is as efficient and ecologically sustainable as possible. To minimize these effects and at the same time ensuring the safety of operation, more refined risk determination methods are required to effectively protect air and sea operations by leaving less space for unnecessary safety margins. As different approaches may yield different results, an international accepted framework for such calculations would be beneficial. To consider the basis for a process of international harmonization, the first step is to collect and compare common risk management practices. Many states do not have yet a national standard for launch and re-entry safety. Hence, other industrial sectors, especially aviation, and their way of handling risks to the general public are presented in this paper, additionally to already existing safety requirements in space transportation. The aim is to establish a summary of how risk is managed in different industries and countries and the way of determining it, that may support the development of a future international standard to ensure launch and re-entry missions are safe and efficient.