Journal of Space Safety Engineering最新文献

This paper discusses High Level Architecture (HLA) based simulation in the context of designing safety into space vehicles. Distributed simulation plays an important role to fuse the two worlds of safety on the one hand and cost effectiveness on the other hand. HLA represents a simulation system architecture framework standard and focuses on interoperability and reusability of simulation components. The article analyzes the impact of the usage of the future HLA version called HLA 4 on space vehicle design. New possibilities with an increased level of loose component coupling in combination with the establishment of a-priori interoperability by using the Space Reference Federation Object Model (SpaceFOM) standard are presented.

During orbital rendezvous, the spacecraft typically approach in the same orbital plane, and the phase of the orbit eventually aligns. Potential rendezvous and docking missions need to be emulated and tested in an on-ground facility for micro-gravity research prior to meeting the harsh conditions of space environment. For orbital docking, the velocity profile of the two spacecraft must be matched. The chaser is placed in a slightly lower orbit than the target. Since all these tasks are quite complex and the realization of space missions are very expensive, any space-related hardware or software’s performance must be tested in an on-ground facility providing zero gravity emulation before initiating its operation in space. This facility shall enable emulation conditions to mimic pseudo zero gravity. It is of critical importance to be equipped with all the necessary ”instruments and infrastructure” to test contact dynamics, guidance, navigation and control using robotic manipulators and/or floating platforms. The Zero-G Laboratory at the University of Luxembourg has been designed and built to emulate scenarios such as rendezvous, docking, capture and other interaction scenarios between separate spacecraft. It is equipped with relevant infrastructure including nearly space-representative lightning conditions, motion capture system, epoxy floor, mounted rails with robots, capability to integrate on-board computers and mount large mock-ups. These capabilities allow researchers to perform a wide variety of experiments for unique orbital scenarios. It gives a possibility to perform hybrid emulations with robots with integrated hardware adding pre-modeled software components. The entire facility can be commanded and operated in real-time and ensures the true nature of contact dynamics in space. The Zero-G Lab also brings great opportunities for companies/startups in the space industry to test their products before launching the space missions. The article provides a compilation of best practices, know-how and recommendations learned while constructing the facility. It is addressed to the research community to act as a guideline to construct a similar facility.

To reduce the risk of explosion of propellant tanks of expended spacecraft and launch vehicles with liquid rocket engines in orbit, as well as in case of emergency situation, for example, loss of orientation, the Inter-Agency Space Debris Coordination Committee recommends passivation measures, including the discharge of residual liquid propellant and pressurant gas. In ANSYS-Fluent program complex possible initial positions of liquid propellant residues in a spherical tank at its rotation under conditions of low gravitational fields are determined. The values of liquid propellant residues depending on their initial position in the spherical tank at opening of the drain line for discharge of gas–liquid mixture into the ambient space are determined. The concept of formation of two-phase flows of liquid propellant on the example of the spherical tank at tangential entry of compressed gas is offered. The relationship between the number of gas inlet points and the effectiveness of the developed method (expressed as the ratio of the mass of expelled liquid propellant to the mass of gas expended) is demonstrated. For instance, the use of 2 gas inlet points achieves an efficiency of up to 30 %, while employing 3 gas inlet points increases it to 89 %.

The development of novel space nuclear systems by governments and companies can greatly enhance space exploration, commerce, and defense capabilities. However, the predominant safety framework for space nuclear in soft law and in practice focuses narrowly on launch safety. A Lifecycle Mission Safety Framework provides a new heuristic to guide system designers, mission planners, regulators, and international law for safety across the broad range of space nuclear applications. It expands safety goals beyond protection of the terrestrial population to workers and astronauts, as well as to activities in orbital space and planetary surfaces. By defining mission phases and identifying safety considerations in each, this framework provides for proactive identification and management of risk.

In the automotive industry, the importance of systems is increasing, and systems become more complex and larger. It is essential to ensure safety of vehicles which has complex and large systems. With the increase in cybersecurity risks due to systemization and connectivity of cars, and the evolution of automated driving technology, it is essential to ensure the safety of connected and automated driving vehicles. In accordance with this automotive industry's changing context, the three standards have come out. Those are ISO 26262 on Functional Safety, ISO/SAE 21434 on Cybersecurity, and ISO 21448 on Safety Of The Intended Functionality related to automated driving. This paper describes the approach of integrated management of Functional Safety, Cybersecurity and Safety of the intended functionality.

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.