Journal of Space Safety Engineering最新文献

Autonomous Flight Termination Systems (AFTS) are used to terminate potentially dangerous trajectories of flight vehicles and rockets before they impose an unacceptable risk to humans or assets. In the FTSnext project a system design and software prototype of an AFTS specifically for the international market of orbital microlaunchers was developed. The system design was obtained following the model-based system engineering approach. The onboard software prototype was implemented in MATLAB. Furthermore, a simulator was developed in Simulink and ASTOS to test the AFTS in nominal, failure, and near-failure trajectories. In all simulated failure trajectories, the FTSnext prototype triggers the desired termination action. The adaptability to several launchers and nominal trajectories can be shown. The performance of the core functions sensor fusion and instantaneous impact point calculation were assessed with Monte Carlo simulations.

Approximately 70 % of launches in 2022 resulted in an uncontrolled rocket body reentry, creating an unnecessary casualty risk to people on the ground, at sea, and in aircraft. Rocket bodies have masses ranging from tens of kilograms to 20 tonnes. Using known rocket body masses and correlations between mass and casualty area, we present revised estimates for the expected risk, finding a 20–29 % probability of one or more casualties over the next decade.

Some states use a 1-in-10,000 threshold for accepting an uncontrolled reentry casualty risk when approving a space activity. This threshold, which is not universally agreed upon, represents a risk acceptance by one country, but imposed on the world population. As the use of space expands, with a record 180 successful launches in 2022, states and other launch providers should adopt technologies and mission designs that ensure controlled reentries. Uncontrolled reentries, particularly of large rocket bodies, constitute an unsafe and unnecessary practice.

Resistojet is a thruster based on electrothermal propulsion which uses heating element to increase the temperature of the thruster, so the propellant ionizes and gives out thrust at the nozzle section. Given their high propulsive performance, resistojets are widely used in satellite technology for control, tangential orbit modification, and propulsion. Therefore, numerous experimental and numerical research was carried out to comprehend the performance of a resistojet. The four major elements of a resistojet thruster are the material for the heating element, the cooling system, the type of nozzle and the choice of propellant. The combination of these four major elements matters greatly to design an efficient resistojet thruster. The main objective here is to compare and analyze the existing high performance resistojet thrusters. Therefore, it is critical to comprehend how well the four major elements of a resistojet thruster perform under different conditions. A resistojets’ performance is greatly affected by the design of the thruster. The right choice of propellant plays an important role with respect to the performance of a resistojet thruster. Every propellant type used up to this point has been thoroughly analyzed with respect to its effect on the resistojets’ thrust and specific impulse values. Parallelly, several cooling system and flow channel designs were examined to a great extent keeping the metrics of a resistojet in mind. A thruster's nozzle is a part that enables hot gases to escape at a higher velocity. Hence, version of nozzle types was studied, and their performances are charted in this paper. In addition to the performance characteristics, future aspects of the resistojet in electric propulsion has been discussed.

In recent times, the explosion of digital appliances and radio communication systems has triggered an elevated debate over electromagnetic interference (EMI) in numerous industries, including the aerospace sector. EMI can disrupt verbal exchange systems, navigation gadgets, or even crucial flight controls. This paper aims to explore the need for EMI protection in the context of discussing the techniques and packages of nanocomposites used for effective shielding. It broadly covers the introduction to EMI shielding, strategies for effective shielding, and the utilization of advanced nanocomposites for EMI mitigation in aircraft. The paper also highlights the amplifying dependence on digital devices in the current aircraft and highlights the increasing coercion of EMI that leads to the demand for strong EMI-protecting solutions. Different EMI shielding techniques based on their effectiveness in protecting sensitive digital components from electromagnetic disturbances are discussed. The use of techniques such as EMI filters, shielded cables, and Faraday cages are investigated for applicability in distinctive aerospace appliances. The emerging requirement for slender and flexible EMI shielding materials that has resulted in the development of conductive polymer nanocomposites in recent years and the use of nanocomposites with excellent EMI shielding regardless of their sustaining mechanical properties has been discussed in detail. Different methods like in-situ polymerization, solution blending, layer-by-layer assembly, and electrospinning are also discussed. In conclusion, the importance of EMI protection in ensuring the dependable and stable operation of modern aircraft and the utility of polymer nanocomposites, a promising method to deal with EMI-related challenges in making air travel more secure and greener in the digital age has been impressed upon.

The purpose of the research is to demonstrate an application of the existing methodology for risk assessment Failure Mode and Effect Criticality Analysis (FMECA) in nanosatellite projects together with a risk register proposal elaborated based on a literature review and expert interviews. The paper also elaborates on the integration of FMECA and knowledge capture and transfer technique. Literature evidence and the use case of the VZLUSAT-1 CubeSat show that it is challenging to implement proper project management and especially risk management practices into nanosatellite (or CubeSat) projects. The risks identified are mostly connected with the technical part, design, and operation of the satellite, and personal, financial, stakeholder, or managerial risks are omitted. The mission success rate can be significantly improved when risks are adequately considered at stages preceding the launch and operation of the satellite.

In compliance with ISO 24,113 and ESA Space Debris Mitigation requirements, spacecrafts in Low Earth Orbit (LEO) must be removed from their operational orbit within 25 years and re-enter the Earth's atmosphere having an on-ground casualty risk lower than 1 in 10,000.

To maximize the number of uncontrolled re-entries, which have much less impact on system mass and costs, ESA's Clean Space initiative is investigating design for containment (D4C) techniques and collaborating with European industries and space agencies to assess, model, analyse, and test new concepts through re-entry tools and plasma wind tunnel experiments. The main objectives are to understand the survivability of materials and techniques suitable for different containment concepts, to improve re-entry modelling, and implement effective D4C measures.

This paper shows the results of these activities, that have been the first milestones in the knowledge of D4C, although further investigations are needed.