Propulsion Technology Research Articles

Pathways in the governance of shipping decarbonization from perspective of balancing the conflicting interests

The shipping industry is featured by high carbon emissions. The 2023 IMO Strategy on Reduction of GHG Emissions from Ships sets forth the global goals of shipping decarbonization. Shipping decarbonization involves complicated issues of economy, technology, policy and law etc., and implies the conflicts between economic interests and environmental interests, between individual interests and public interests, between individual States’ interests and international common interests and between current interests and long-term interests. This research suggests that balancing such conflicting interests need to follow the principle of prioritizing the international public environmental interests while taking into account the other interests because protection of environmental interests should be taken as the basic value orientation in shipping decarbonization governance and the principle of collaborating governmental intervention and market mechanisms by reference to the theory on the relationship between government and market in economics. Under the guidance of these principle, by reference to the equilibrium analysis method in economics and following the progressive decision theory in management, this research demonstrates that the main pathways in achieving such balance may include: making strategic plan and basic policy for reducing GHG emissions from ships by the government, implementing economic incentive policies such as tax incentives and fiscal subsidies, implementing ship energy efficiency measures, prudently implementing shipping carbon emissions trading mechanism, accelerating the establishment of alternative marine fuel supply chain, innovating alternative marine fuel technology and ship propulsion technology, and actively engaging in international cooperation.

Case Study of an Integrated Design and Technical Concept for a Scalable Hyperloop System

This paper presents the design process and resulting technical concept for an integrated hyperloop system, aimed at realizing efficient high-speed ground transportation. This study integrates various functions into a coherent and technically feasible solution, with key design decisions that optimize performance and cost-efficiency. An iterative design process with domain-specific experts, regular reviews, and a dataset with a single source of truth were employed to ensure continuous and collective progress. The proposed hyperloop system features a maximum speed of 600 kmh and a capacity of 21 passengers per pod (vehicle). It employs air docks for efficient boarding, electromagnetic suspension (EMS) combined with electrodynamic suspension (EDS) for high-speed lane switching, and short stator motor technology for propulsion. Cooling is managed through water evaporation at an operating pressure of 10 mbar, while a 300 kW inductive power supply (IPS) provides onboard power. The design includes a safety system that avoids emergency exits along the track and utilizes separated safety-critical and high-bandwidth communication. With prefabricated concrete parts used for the tube, construction costs can be reduced and scalability improved. A dimensioned cross-sectional drawing, as well as a preliminary pod mass budget and station layout, are provided, highlighting critical technical systems and their interactions. Calculations of energy consumption per passenger kilometer, accounting for all functions, demonstrate a distinct advantage over existing modes of transportation, achieving greater efficiency even at high speeds and with smaller vehicle sizes. This work demonstrates the potential of a well-integrated hyperloop system to significantly enhance transportation efficiency and sustainability, positioning it as a promising extension to existing modes of travel. The findings offer a solid framework for future hyperloop development, encouraging further research, standardization efforts, and public dissemination for continued advancements.

Exploring Differing Perspectives on Sustainability and Corresponding Strategies in German Automotive Companies

In addition to acute crises dominating the societal discourse, such as the global consequences of the COVID-19 pandemic and the Russian invasion of Ukraine, the world continues to face the ongoing challenge of limiting climate change and achieving a sustainable transformation. Yet, in public discourse, the widely used terms “sustainability” and “transformation” are not clearly defined, and the understanding varies greatly depending on the industry and the stakeholders considered. One important transformation arena lies within the German automotive industry, as it is one of the country’s biggest industrial sectors by revenue and the number of employees. In addition, the German automotive industry is currently going through a transition period due to the switch to electric drivetrains as the main propulsion technology opposed to combustion engines. Therefore, the following paper identifies the differing understandings of sustainability and according actions in the German automotive industry. Moreover, possible conflicts and prioritizations along the economic, ecological, and social dimensions of sustainability are presented based on an expert interview study. To do so, a structuring qualitative content analysis in combination with a descriptive approach was used focusing on the differing perspectives on sustainability of both the interviewees and their companies. The gathered data then allows to compare the aggregated individual and corporate sustainability perspectives in the German automotive industry, as well as comparing the sustainability perspectives of the interviewees and their respective companies case by case. The results suggest that there is a considerable discrepancy between individual and corporate understandings of sustainability. These differences can mainly be attributed to the companies’ economically driven views in contrast to the individuals’, mostly ecologically driven sustainability perspective. Moreover, several barriers and conflicts, rooted in the prioritization of economic gains, can be traced back to conflicts in the supplier pyramid. The identification of common transformation goals and measures among companies is necessary to enable a collaborative, sustainable transformation in the German automotive industry, which benefits all societal stakeholders in or attached to this sector.

FOREWORD AND FAREWELL

As I write my final foreword as Editor-in-Chief of the Journal of Naval Sciences and Engineering (JNSE), it is with deep gratitude and pride that I look back on the transformative progress we have achieved together. I first took on this role with the responsibility of publishing the second issue of 2022, just as the journal transitioned from the Naval Sciences and Engineering Institute to the Turkish Naval Academy (TNA). Now, following my promotion to Rear Admiral (Lower Half) and my appointment as the Deputy General Manager of Naval Shipyards, I prepare to step down, filled with confidence in the journal's future impact. During my tenure, JNSE has not only expanded its reach but also evolved in structure. As the first Editor-in-Chief after this significant transition, I established a structured workflow to ensure the smooth handling of the journal’s workload. This progress would not have been possible without the unwavering support of our esteemed contributors, editors, reviewers, and readers, who have collectively strengthened the journal’s place as a respected publication in naval sciences and engineering. Naval sciences and engineering have always been at the forefront of the Turkish Navy’s priorities, with an increasing emphasis on innovation and self-reliance in defense capabilities. As researchers and engineers, our collective work—through publications like this journal—contributes, even if indirectly, to these larger goals. It is essential to recognize that advancements in naval platforms, weaponry, and defense systems depend heavily on foundational research in science and technology. Every study, every paper, and every breakthrough—however modest it may seem—plays a role in building the knowledge base that supports these ambitious naval goals. In this foreword, I highlight recent and ongoing projects of the Turkish Navy, from initial concepts to construction, to offer future contributors an idea of impactful areas of study. Research in fields like autonomous systems, AI-driven operations, and advanced propulsion technologies can shape the Navy’s future capabilities. As the quote often attributed to Faraday or Franklin reminds us, "What is the use of a newborn baby?" Theoretical research, like this newborn, may not reveal its full utility immediately, yet it holds the potential to make profound impacts over time. (Full foreword available in the PDF version.) As I transition from this role, I am proud of the journal’s achievements. One of the most notable milestones has been the introduction of Digital Object Identifiers (DOIs) for all published papers since the second issue of 2022. This change has allowed for greater visibility, wider dissemination, and immediate online publication, which are crucial in the fast-paced world of research. Additionally, reorganizing the editorial team, including the appointment of key roles such as the Technical Editor, Layout Editor, and Secretariat from the capable staff of the TNA has ensured a streamlined workflow and elevated the journal's standards. The December 2024 issue is a testament to the journal’s interdisciplinary reach. This issue includes four valuable studies: one presenting a robust planning model for irrigation, a topic of relevance as climate change increasingly impacts maritime and agricultural resources; a second, developing a cybersecurity perception scale for maritime industry employees, reflecting the growing importance of cybersecurity in naval operations; a third, a performance analysis of adaptive MIMO techniques for visible light communication, which holds promise for improving naval communication systems; and finally, a paper on thyroid nodule segmentation using ultrasound, which highlights how advances in medical imaging can also improve healthcare aboard naval vessels. These papers, though diverse, reflect the journal's goal of fostering interdisciplinary innovation. As I conclude my tenure as Editor-in-Chief, I want to express my gratitude one last time to the readers, the dedicated editors who served alongside me, and the referees who ensured the quality of the research we published. It has been a privilege to oversee the journal through significant milestones, and I deeply appreciate the effort and commitment of everyone involved. Reflecting on my tenure, I am particularly proud of the journal's growth, both in scope and influence. Over these years, we have not only expanded our reach but have also contributed to shaping the dialogue around the future of naval technology. Though this marks the end of my tenure, I depart with the satisfaction of knowing that we have upheld the highest standards in naval science and engineering research. As I bid farewell, I leave with the hope that the journal continues to inspire and contribute to the advancement of naval sciences. May your journey be swift and your destination secure. Fatih ERDEN, Ph.D. Editor-in-Chief

Analysis of azimuthal electron current driving by rotating magnetic field in field-reversed configuration electric propulsion

Field-reversed configuration electric propulsion is an advanced space electromagnetic propulsion technology with significant application prospects but poor thrust performance. To delve into the intrinsic physical mechanisms, a model of the rotating magnetic field penetrating into the plasma and azimuthal electron current driving was developed. The simulation results show that rotating magnetic field strength, frequency, and initial seed plasma density are the key factors that exist as an optimal threshold. Specifically, the rotating magnetic field feed current (i.e., magnetic field strength) was not less than 1000 A, the rotating magnetic field frequency was ∼200–300 kHz, and the plasma density was approximately 1 × 1018 m−3 order of magnitude.

Wave mode observation of hydrogen/oxygen driven rotating detonations in the hollow and annular rotating detonation rocket engine

The rotating detonation rocket engine (RDRE) fueled by hydrogen/oxygen propellant represents a promising propulsion technology due to its high thermodynamic efficiency and propellant superior specific impulse. The rotating detonation wave (RDW) must propagate in a specific propagation mode while maintaining the self-sustaining state to ensure stable operation. An experimental system of hydrogen/oxygen fueled RDRE was developed in the present study. The operation of RDRE and propagation mode of RDW were investigated under atmospheric pressure conditions, and both hollow and annular combustors were tested. The high-frequency pressure fluctuations in the RDRE were measured by the dynamic pressure transducer, while a high-speed camera was used to capture images of flame luminescence at the rear end of the RDRE. The experimental results showed that the RDW could be initiated and reached a self-sustaining propagation state with hydrogen/oxygen propellant in the hollow and annular RDRE. A single-wave mode, a two-wave co-rotating mode, and a three-wave co-rotating mode were visualized under different conditions. With the increase in the equivalence ratio, the number of rotating detonation fronts decreased, and the variations in the RDW propagation modes were consistent in the hollow and annular RDRE. However, when the equivalence ratio exceeds 1.2, the propagation velocity decreases sharply in the annular combustor, while in the hollow combustor the RDW propagates stably, revealing a higher upper limit for the equivalence ratio. Also, the dominant frequency distribution was more concentrated in the hollow combustor. The findings provide valuable insight into the variations in detonation modes related to the equivalence ratio and combustor configuration.

Comparison of Propulsion Options for Interplanetary Missions

This paper investigates propulsion options and trajectory designs for a manned mission from Earth to Mars, followed by a mission to Ceres. It evaluates various propulsion technologies, including traditional chemical propulsion, nuclear thermal propulsion (NTP), and electric propulsion systems such as ion thrusters and Hall effect thrusters. The analysis highlights the limitations of chemical propulsion in terms of energy efficiency and payload capacity while underscoring the potential of NTP to reduce travel time and improve crew safety due to its higher specific impulse. The study also examines the feasibility of solar and nuclear electric propulsion, focusing on their high efficiency and suitability for extended missions, and considers innovative concepts like solar sails and fusion propulsion for their theoretical advantages in thrust and velocity. Low-thrust trajectories are analyzed for their ability to minimize overall delta-V requirements, which is essential for mission success. For the Mars mission, chemical propulsion systems currently under development are evaluated alongside electric propulsion powered by nuclear reactors, which could significantly reduce travel times and propellant needs. The additional challenges of propelling a spacecraft to Ceres, a more distant destination in the asteroid belt, shift the focus to electric propulsion options, particularly advanced nuclear-electric systems, which offer the potential to enable human exploration within a reasonable timeframe. The paper concludes that the optimal propulsion system for a manned mission to Mars and Ceres requires balancing travel time, technical feasibility, and crew safety, emphasizing the necessity for further development of advanced electric propulsion technologies to facilitate ambitious human deep-space exploration.

Hypersonic High Speed Strike Weapons: Design, Research and Development

Hypersonic High-Speed Strike Weapons are a part of advanced weapon technology used in military engagements, designed to travel and sustain speeds of at least Mach 5, which is five times the speed of sound. These specially designed weapons are capable of maneuvering and changing directions unpredictably. In this paper, we explore the advantages of using such weapons, the research behind them, and how their implementation could enhance military engagements. By employing this system of weapons, we can expect quick weapon system activation times and precise deployment regarding targets. This study examines the design, overview, technical aspects, feasibility, advantages, and disadvantages of deploying this weapon technology in real-time use. However, several challenges must be addressed to successfully deploy these weapons systems. The primary challenges associated with the deployment of hypersonic weapons include temperature management, propulsion technology, material science (which is critical due to the high-speed demands), safety and reliability, strategic and ethical considerations, financial and time constraints, testing facilities, and the guidance and control of these systems. Overcoming these challenges through advanced technology and innovative ideas is essential for the successful implementation of Hypersonic High-Speed Strike Weapons (HHSSW) systems. The HHSSW systems hold promise for advancing the current weapons technology that humanity possesses. With proper research and resource allocation for HHSSW systems, we can anticipate their development for applications such as asteroid or comet deflection and, if necessary, space warfare.

Assessing the Impact of Hybrid Propulsion Systems on the Range and Efficiency of Aircraft

The demand for aviation continues to grow, posing issues in terms of fuel consumption, environmental effect, and operational efficiency. In addition, the COVID-19 pandemic has also highlighted the need for sustainable solutions in the aviation sector. To address these issues, hybrid electric propulsion systems have emerged as a potential option. Hybrid electric propulsion systems have the potential to improve airplane performance while reducing environmental impact. This article looks into the effects of hybrid electric propulsion technologies on optimal aircraft range. The study looks at aviation's environmental impact, several hybrid aircraft prototypes, and battery capacity and density challenges. Fuel usage increases in proportion to the weight of the aircraft. As a result, the range is shorter. In modern technology, along with to the added weight of batteries used as energy storage in hybrid propulsion systems, there are low battery densities and capacities. When the researches were reviewed, it was discovered that overcoming these limitations was easier for small aircraft and more difficult for large aircraft. As a consequence of the studies and research conducted, the development of light and reliable batteries with high energy density and capacity would expand the range of hybrid aircraft and allow them to be used more efficiently over long distances.

Digital twins for electric propulsion technologies

As the space industry is undergoing an evolution, the current approaches toward design, development, and qualification of Electric Propulsion (EP) systems largely based on empirical “trial-and-error” methodologies are falling short of addressing the emerging needs and keeping abreast of the rapid changes in market trends. Furthermore, with the proliferation of Artificial Intelligence (AI) within the space industry toward next-generation autonomous satellites and spacecrafts, the conventional EP monitoring and control strategies become inadequate and need to give way to approaches compatible with satellite-level autonomy requirements. A digital twin (DT) – a technology capable of providing an accurate dynamically adapting virtual representation of a physical asset – is a game-changing concept that catalyzes the transcendence of the EP industry past its pressing challenges today. In this paper, we aim to: (i) define the DT concept, highlighting how it surpasses traditional modelling, (ii) enumerate the DT’s breakthrough promises for the EP industry, and (iii) specify the challenges to realize practical and scalable EP DTs. Additionally, we report on the technical progress achieved and/or planned at Imperial Plasma Propulsion Laboratory to fill the foundational gaps in three building block elements of DTs, namely, (i) a cost-effective kinetic model to generate extensive high-fidelity databases for machine learning (ML), (ii) ML-enabled models for prediction and analysis of performance and operational behavior, and (iii) a DT architecture that integrates the numerical models in terms of a computing infrastructure and provides data pipelines and interfaces for the DT’s data exchanges with the real world, its dynamic updating, and uncertainty quantification.

Review of diver propulsion vehicle: A review

The ocean serves as a vital arena for resource exploitation, scientific inquiry, and strategic endeavors. Among the array of underwater propulsion technologies, diver propulsion vehicles (DPVs) stand out for their exceptional integration, concealability, and maneuverability. They hold a pivotal role in both marine scientific exploration and military operations beneath the waves, thus carrying significant research implications. However, the existing literature on DPVs remains limited, lacking comprehensive examinations of their design processes and parameters. This review systematically surveys and assesses the current landscape of DPV development and research. Three key facets—propeller design, performance assessment, and equipment engineering—are scrutinized and analyzed. By consolidating essential data from ongoing studies, this review offers valuable insights. Additionally, it forecasts potential directions and emerging focal points in the evolution of underwater propulsion for frogmen, drawing from current advancements. The objective is to furnish foundational data to support the design and study of frogman underwater propulsion systems, thereby advancing engineering applications in this domain.

Impact of automation and zero-emission propulsion on design of small inland cargo vessels

Abstract Small inland waterways offer considerable capacity for modal shift of cargo transport. Revitalization of smaller inland waterways, however, may require new vessel designs as most of the existing small vessels are outdated and incompatible with the present state of the technology development and the current commercial and regulatory requirements. This paper investigates the possibilities for modernization of small inland vessel designs and offers a systematic analysis of impact of “automation” and “zero-emission propulsion technology” on reference designs of standard European inland cargo vessels of CEMT classes I, II, III, and IV. The adopted level of automation enables the vessels to be remotely operated without human crew onboard, whereas the adopted zero-emission propulsion concept is based on electrification of the powertrain. The paper identifies the impacts of the modernization on general arrangement, cargo capacity, safety, structural design, etc. and indicates the vessel classes which could be the most promising candidates for the design of a future small autonomous inland ships.

Laser Propulsion Science and Technology

Laser propulsion is an advanced technology that holds promise for use in many aerospace propulsion applications [...]

Cathode-less RF plasma thruster design and optimisation for an atmosphere-breathing electric propulsion (ABEP) system

Atmosphere-breathing electric propulsion (ABEP) is a concept that ingests residual atmospheric gases as a source of propellant for an electric thruster, removing the need for onboard propellant storage. This would enable continuous low-thrust drag compensation, extending the lifetime of spacecraft in Very-Low Earth Orbit (VLEO); <250 km. VLEO is an appealing region for spacecraft operations, enabling new remote sensing missions with improved radiometric performance and spatial resolution, whilst reducing size, mass and power requirements, as well as mission cost. A preliminary design review and optimisation is therefore conducted for an ABEP system that uses the cathode-less radio frequency (RF) plasma thruster from Technology for Innovation & Propulsion (T4i) S.p.A. This removes the issue of thruster erosion by means of magnetic confinement and offers reduced susceptibility to varying atmospheric composition. A semi-empirical oxygen-nitrogen global source model (GSM) has been developed which considers the volume-averaged flux, momentum, and energy balance of the RF discharge. This includes a detailed chemistry model for the complex electron-molecular reactions and energy-loss channels of air plasma in the ionisation chamber. The GSM is coupled to an analytical model of flux balance for an air intake, verified by Direct Simulation Monte-Carlo (DSMC) simulation, to consider its design for maximum collection efficiency. This is then utilised in a robust multi-objective optimisation of the ABEP system, accounting also for spacecraft aerodynamics and power requirements.

Review Research Paper of Feasibility study on Anti-Gravity Effect for Advance Propulsion system and technologies

The concept of anti-gravity, often portrayed in science fiction as a means to counteract or negate the effects of gravitational force, has intrigued scientists and enthusiasts alike for decades. This paper explores the feasibility of achieving anti-gravity effects through various theoretical and experimental perspectives. Firstly, theoretical frameworks such as general relativity and quantum mechanics are reviewed to understand gravity and its potential manipulation. While these theories provide foundational insights, they also highlight the immense challenges involved in directly counteracting gravitational forces due to their fundamental nature. Next, experimental efforts and hypothetical technologies proposed in scientific literature are examined. Concepts such as negative mass, exotic matter, and gravitational shielding are discussed in terms of their theoretical underpinnings and practical limitations. Experimental evidence, including anomalies in gravitational measurements and speculative engineering proposals, are scrutinized to evaluate their relevance to achieving anti-gravity effects. Furthermore, the paper addresses the technological and ethical implications of developing anti-gravity technology. Considerations such as energy requirements, environmental impact, and societal readiness are explored to provide a holistic perspective on the feasibility and desirability of pursuing anti-gravity research. Ultimately, while the idea of anti-gravity remains a captivating subject of scientific inquiry and fiction, current understanding and technological capabilities suggest significant hurdles that must be overcome before practical anti-gravity effects can be realized. This paper concludes by outlining potential avenues for future research and highlighting the interdisciplinary nature of addressing such a complex phenomenon.

Research on Aircraft Engines and Advanced Power in Land, Sea and Air

This paper provides a comprehensive overview of advanced propulsion technologies in military applications across land, sea, and air domains. It examines the theoretical foundations of propulsion systems, tracing the evolution of aircraft engines from early piston designs to modern jet propulsion. The study explores current state-of-the-art technologies, including advanced turbofan engines, hybrid electric systems, and nuclear propulsion for naval vessels. Special attention is given to emerging fields such as unmanned aerial vehicle propulsion, hypersonic technologies, and stealth engine designs. The research also delves into futuristic concepts like magnetohydrodynamic propulsion and pulse detonation engines. Throughout the analysis, common themes of improved efficiency, enhanced power-to-weight ratios, and increased operational capabilities are highlighted. This paper aims to provide a holistic view of the current landscape and future trajectory of military propulsion technologies, underlining their critical role in shaping modern warfare capabilities.

Review of Solar Sail Propulsion Mechanisms and Missions for Space Travel

Since solar sailing employs the speed of sunlight to drive spacecraft, it is an efficient and environmentally friendly alternative to traditional propulsion technologies. The physics of photon compression, the significance of novel materials and systems that enhance sailing performance, and the appropriate testing of solar sailing systems are all covered in this research paper. The main solar sailing projects— LightSail, NEA Scout, and IKAROS—are examined in this paper, and their merits, demerits, and contributions to the field are discussed. Potential solar sailing technology for extended space travel are also covered, along with space sustainability. Consider how crucial it is for space exploration in the future. The goal of this research is to demonstrate the transformative potential of navigation and to spark further developments in the exciting field of space aerospace engineering by effectively integrating mission data and current research in the ever-changing landscape of space exploration. Since solar sailing employs the speed of sunlight to drive spacecraft, it is a practical and environmentally friendly alternative to traditional propulsion technologies. The physics of photon compression, the significance of novel materials and systems that enhance sailing performance, and the appropriate testing of solar sailing systems are all covered in this research paper. The main solar sailing projects—LightSail, NEA Scout, and IKAROS—are examined in this paper, and their merits, demerits, and contributions to the field are discussed. Potential solar sailing technology for extended space travel are also covered, along with space sustainability. Pay attention to how crucial it is for future space exploration. Through the efficient integration of mission data and current research, this project seeks to address the dynamic landscape of space exploration in the industry and encourage future advancements in the exciting field of space aeronautical engineering. Additionally, it aims to illustrate how navigation can have a transforming effect. Keywords: Space Exploration, Propulsion Technology, Interstellar Travel, Spacecraft Navigation, Attitude control, Trajectory optimization, Material Durability, Deep Space Missions, Interplanetary Travel, Solar Radiation Effect, Photon Pressure, Solar sail Deployment, Orbital Mechanics, Continues Thrust.

Net-Zero Greenhouse Gas Emission Electrified Aircraft Propulsion for Large Commercial Transport

Until recently, electrified aircraft propulsion (EAP) technology development has been driven by the dual objectives of reducing greenhouse gas (GHG) emissions and addressing the depletion of fossil fuels. However, the increasing severity of climate change, posing a significant threat to all life forms, has resulted in the global consensus of achieving net-zero GHG emissions by 2050. This major shift has alerted the aviation electrification industry to consider the following: What is the clear path forward for EAP technology development to support the net-zero GHG goals for large commercial transport aviation? The purpose of this paper is to answer this question. After identifying four types of GHG emissions that should be used as metrics to measure the effectiveness of each technology for GHG reduction, the paper presents three significant categories of GHG reduction efforts regarding the engine, evaluates the potential of EAP technologies within each category as well as combinations of technologies among the different categories using the identified metrics, and thus determines the path forward to support the net-zero GHG objective. Specifically, the paper underscores the need for the aviation electrification industry to adapt, adjust, and integrate its EAP technology development into the emerging new engine classes. These innovations and collaborations are crucial to accelerate net-zero GHG efforts effectively.

Thermodynamic and propulsive characterization of nitro-substituted quadricyclane

This investigation delves into the potential of Octa-nitro Quadricyclane (ONQC), a nitro-substituted quadricyclane, as a next-generation energetic material. Employing a robust B3LYP-gCP-D3/6-31G(d) computational approach, the study evaluates key material properties of ONQC, including strain energy (700.2 kJ/mol), enthalpy of formation (668.6 kJ/mol), and density (2.08 g/cm³). These enhanced properties result in predicted increases of 124 % in detonation pressure and 49.5 % in detonation velocity compared to TNT, significantly surpassing the performance of conventional high-energy density materials. Additionally, ONQC's suitability as an energetic additive in bipropellant formulations was evaluated with NASA's Chemical Equilibrium with Applications (CEA) software. The primary focus was on bipropellant formulations employing kerosene-based fuels (RP-1, JP-10, JP-5, etc.) and liquid oxygen (LOX) as the oxidizer. Incorporating ONQC into propellant formulations provides substantial improvements in specific impulse and reduces oxidizer requirements. This makes ONQC a promising candidate for advancing propulsion technology.

Reinforced Lyapunov controllers for low-thrust lunar transfers

Future missions to the Moon and beyond are likely to involve low-thrust propulsion technologies due to their propellant efficiency. However, these still present a difficult trajectory design problem, owing to the near continuous thrust, lack of control authority and chaotic dynamics. Lyapunov control laws can generate sub-optimal trajectories for such missions with minimal computational cost and are suitable for feasibility studies and as initial guesses for optimisation methods. In this work a Reinforced Lyapunov Controller is used to design optimal low-thrust transfers from geostationary transfer orbit towards lunar polar orbit. Within the reinforcement learning (RL) framework, a dual-actor network setup is used, one in each of the Earth- and Moon-centred inertial frames respectively. A key contribution of this paper is the demonstration of a forwards propagated trajectory, removing the need to define a patch point a priori. This is enabled by an adaptive patch distance and extensive initial geometry exploration during the RL training. Results for both time- and fuel-optimal transfers are presented, along with a Monte Carlo analysis of the robustness to disturbances for such transfers. Phasing is introduced where necessary to aid rendezvous with the Moon. The results demonstrate the potential for such techniques to provide a basis for the design and guidance of low-thrust lunar transfers.